# 310.15 (B) (7) Reduced Service Feeder



## brian john (Mar 11, 2007)

2/0 cu


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## lighterup (Jun 14, 2013)

I use 4/0 AL in parallel


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## Dennis Alwon (May 9, 2009)

brian john said:


> So in lieu of the old table, you use the 83% rule and can reduce the feeder size. BUT if I have a 320-meter feeding two separate 200 amp panels does your AHJ allow 2/0 to each separate panel.
> 
> Seems logical they would BUT?? Logic does not always follow the NEC.


That would not be compliant but some get away with it


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## Dennis Alwon (May 9, 2009)

The reason it is not compliant is that (B)(7) states that the service conductors must carry the entire load of the service. Since each set of conductors only do 200 amps then the 83% is not in play.


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## Dennis Alwon (May 9, 2009)

lighterup said:


> I use 4/0 AL in parallel


Are you saying you use a 400 amp panel? Because if you are talking about 2-
200 amp panels then that is really not in parallel but I understand what you are saying


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## lighterup (Jun 14, 2013)

Dennis Alwon said:


> Are you saying you use a 400 amp panel? Because if you are talking about 2-
> 200 amp panels then that is really not in parallel but I understand what you are saying


If I do a 400 amp service (residential) I will use the 320 amp meter
socket ...my service laterals would normally be 4/0 URD in parallel
unless longer more substantial distances are involved to POCO
X-former.

I usually will use (1) 4" conduit for the riser and bring both sets of
4/0 into the meter socket enclosure

I install double lugs on the line side of the meter socket enclosure
and land the service laterals in those



I use (2) 200 amp main breaker panels indoors and there would be
2 two inch LB's coming out the bottom of the meter socket and
both would 90 into the 200 amp panels which would be in the basement
directly below.

I also use double lugs on the load side of the meter socket enclosure.

I send (1) 3 wire 4/0 AL URD for each panel.

The reason we don't use CU is strictly cause of cost differences...saves
a few bucks.


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## Dennis Alwon (May 9, 2009)

My point was that 2 sets of 4/0 going from the meter load side to each panel with one set is not a parallel connection. Since Brian was stating 2- panels I thought you were calling those run parallel


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## Arrow3030 (Mar 12, 2014)

brian john said:


> So in lieu of the old table, you use the 83% rule and can reduce the feeder size. BUT if I have a 320-meter feeding two separate 200 amp panels does your AHJ allow 2/0 to each separate panel.
> 
> Seems logical they would BUT?? Logic does not always follow the NEC.


It isn't logical that it isn't compliant, but it isn't compliant. 

I think this is the third this week on B7. It's such a mess of a rule.


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## frenchelectrican (Mar 15, 2007)

brian john said:


> So in lieu of the old table, you use the 83% rule and can reduce the feeder size. BUT if I have a 320-meter feeding two separate 200 amp panels does your AHJ allow 2/0 to each separate panel.
> 
> Seems logical they would BUT?? Logic does not always follow the NEC.


If each panel have it own main OCPD that is not the moot there unless you got single 400 main OCPD ahead of it. that can change the game on that.

Per my codes we can use 2/0 cu only if it have it own OCPD plus under 160 amps. 

otherwise the 3/0 cu or 250 al will meet this pretty easy.


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## lighterup (Jun 14, 2013)

Dennis Alwon said:


> My point was that 2 sets of 4/0 going from the meter load side to each panel with one set is not a parallel connection. Since Brian was stating 2- panels I thought you were calling those run parallel


oh I see

I'm saying the service entrance conductors are
parallel cause they both originate from double lugs

I have used single phase 400 amp mains .Those just get one 3 wire
service entrance conductor


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## Dennis Alwon (May 9, 2009)

lighterup said:


> oh I see
> 
> I'm saying the service entrance conductors are
> parallel cause they both originate from double lugs
> ...


To be parallel they must both begin and end in the same place or as the code states electrically joined at both ends


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## Dennis Alwon (May 9, 2009)

Arrow3030 said:


> It isn't logical that it isn't compliant, but it isn't compliant.
> 
> I think this is the third this week on B7. It's such a mess of a rule.


There is some logic to it. If the nec can be guaranteed that an install will be done where the loads are shared equally between the panels it may sway the panel. 

What happens, as I have seen it, is that the electrician will take all the heavy loads like electric heat and heat pumps all from one panel. On large homes you can have a situation where the calculated load would require a full sized service conductor and not the 83%. There is no diversity when one panel is loaded like that so they just decided to lay it safe and require the service conductor or feeder to carry the entire load.


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## HackWork (Oct 2, 2009)

Dennis Alwon said:


> There is some logic to it. If the nec can be guaranteed that an install will be done where the loads are shared equally between the panels it may sway the panel.
> 
> What happens, as I have seen it, is that the electrician will take all the heavy loads like electric heat and heat pumps all from one panel. On large homes you can have a situation where the calculated load would require a full sized service conductor and not the 83%. There is no diversity when one panel is loaded like that so they just decided to lay it safe and require the service conductor or feeder to carry the entire load.


But it's all based on assumption.

Any 200A service with 4/0 aluminum service conductors can have car chargers or hot tubs added which will do the exact same thing as what you mentioned with the electrician putting all the heat loads in one panel. 

Either it can handle the load that the breaker will allow... or not.


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## Dennis Alwon (May 9, 2009)

HackWork said:


> But it's all based on assumption.
> 
> Any 200A service with 4/0 aluminum service conductors can have car chargers or hot tubs added which will do the exact same thing as what you mentioned with the electrician putting all the heat loads in one panel.
> 
> Either it can handle the load that the breaker will allow... or not.


That is not true...When all the loads are present in one panel there is diversity to a much larger extent then if the loads were separated. The reason we are allowed the 83% is because of the diversity.

I will not argue that in a residence it will ever be an issue but that is where the thinking comes from.


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## HackWork (Oct 2, 2009)

Dennis Alwon said:


> That is not true...


 What I said is completely true. Diversity is meaningless when you got 190 amps worth of vehicle chargers running for 8+ hours. Can 4/0 Al handle that or not? 

Everything that you are talking about is based on an assumption. 

So I maintain that the service entrance conductors should be sized to what the breaker will allow, not cheesy assumptions based on some random electrician's load calculations.


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## Dennis Alwon (May 9, 2009)

HackWork said:


> What I said is completely true. Diversity is meaningless when you got 190 amps worth of vehicle chargers running for 8+ hours. Can 4/0 Al handle that or not?
> 
> Everything that you are talking about is based on an assumption.
> 
> So I maintain that the service entrance conductors should be sized to what the breaker will allow, not cheesy assumptions based on some random electrician's load calculations.


You are giving a very specific and not likely scenario but I do understand. Also If you had 190 amps of chargers then you would have to plan your loads better and you wouldn't have a 200 amp service.....

So, yes, there are some assumptions but I would not call them meaningless as the method has worked forever

Car chargers and electric on demand water heaters have added a new dimension but that would be done in the design stage. Just because the code allows 83% doesn't mean you should use it. You need to wire for the particular situation all the time.


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## HackWork (Oct 2, 2009)

Dennis Alwon said:


> You are giving a very specific and not likely scenario but I do understand.


 It's not likely that a house built by a sterile female will need tamper resistant receptacles either.

But sometime in the future things might change.



> So, yes, there are some assumptions but I would not call them meaningless as the method has worked forever


 I disagree. It only worked because 4/0 Al can handle any load that a 200A breaker will allow. The diversity thing has nothing to do with it working. So since 4/0 can handle that amount of current, that is the conductor size that should be used.



> Car chargers and electric on demand water heaters have added a new dimension but that would be done in the design stage.


 In the real world these things are added later and most electrician would be happy to install them even if the service is tight. Again, it's all based off of assumption. Load calculations are really, really bad guesses. They are never accurate. 



> Just because the code allows 83% doesn't mean you should use it. You need to wire for the particular situation all the time.


 Exactly, and we don't know the situation, ever. We make assumptions but we don't know what the homeowner is going to actually be drawing today, nevermind 20 years from now.


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## Arrow3030 (Mar 12, 2014)

Dennis Alwon said:


> There is some logic to it. If the nec can be guaranteed that an install will be done where the loads are shared equally between the panels it may sway the panel.
> 
> What happens, as I have seen it, is that the electrician will take all the heavy loads like electric heat and heat pumps all from one panel. On large homes you can have a situation where the calculated load would require a full sized service conductor and not the 83%. There is no diversity when one panel is loaded like that so they just decided to lay it safe and require the service conductor or feeder to carry the entire load.


I kinda get what you're saying. Let me rephrase to see if I'm picking it up.

A single family house has a calc load of 300 amps.
The electrician uses a 320 continuous amp meter main with 2 200 amp service disconnect breakers feeding two 200 amp mlos in the building. 
One of the panels has mainly mechanical loads on it and has a calc load of 190 amps. 
The other obviously has a calc load of 110 amps.

And this is where I get confused. Why is the 190 amp panel not allowed to use the 83% rule? Why is this calculated 190 amps not allowed to be on 2/0 cu when the same calcalculated 190 amps in a home with only a 200 amp service Is? 

I have a feeling a lot of it has to do with the NEC expecting electricians to NOT do a load calc so the rules make us play safe. 

IMO, if I have a load calc for a feeder or service I should always be allowed to use the 83% rule. If that doesn't make sense than B7 is a broken rule and should be eliminated.


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## chicken steve (Mar 22, 2011)

Am i reading it correctly that this 83% is everything now?

~CS~


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## Arrow3030 (Mar 12, 2014)

chicken steve said:


> Am i reading it correctly that this 83% is everything now?
> 
> ~CS~


I'm not sure what you mean by everything. It was a table for resi, then it changed to an article a few cycles ago with more words.

Dennis tried to help me understand the logic but I think I'm still missing something.


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## chicken steve (Mar 22, 2011)

I'm under the impression it's everything, not just resi

but could be_ wrong_ Arrow

~CS~


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## Arrow3030 (Mar 12, 2014)

chicken steve said:


> I'm under the impression it's everything, not just resi
> 
> but could be_ wrong_ Arrow
> 
> ~CS~


You are. 

There is a 2017 revision that allows the use of the 90c table that's new. Maybe you're thinking of that?


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## RePhase277 (Feb 5, 2008)

chicken steve said:


> I'm under the impression it's everything, not just resi
> 
> but could be_ wrong_ Arrow
> 
> ~CS~


It's only for residential. It used to be table 310.15(B)(7). It's what allowed us to use 4/0 aluminum for a 200 amp service. Now it isn't a table, it just tells you that you can derate to 83% of the conductor ampacity for a residential feeder that carries the entire load of the residence.


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## Dennis Alwon (May 9, 2009)

Arrow3030 said:


> I'm not sure what you mean by everything. It was a table for resi, then it changed to an article a few cycles ago with more words.
> 
> Dennis tried to help me understand the logic but I think I'm still missing something.


You got the gist of it all... I believe the reason we are allowed to reduce the size of the service conductor, when the entire load of the house is on those conductors, is because of diversity.

When you remove certain elements then the diversity disappears.

Suppose, as in your example, one panel had 190 amps of heating loads. Now you want to use 2/0 but 2/0 is really only good for 175 amps. If all the heat units come on at the same time then you are overloading those conductors, whereas, if the panel had other types of loads then the calculated load is not likely to ever reach 190 amps.

A typically 200 amp panel generally never sees anywhere near 125 or 150 amps even with electric heat as the other loads in the home are so diverse that it isn't really possible to get that high a load.

If you had a 190 amps of heat and then the rest of the house added the calculated load would be a lot higher than 200 amps and thus you would need to change the layout and service size.

I know it is a bit odd especially when you remove one load from a panel but this is the way it has been for a long time. Most of the 400 amp services I have seen had 2/0 going to each 200 amp panel and was never an issue... it is just not compliant.


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## HackWork (Oct 2, 2009)

Dennis Alwon said:


> You got the gist of it all... I believe the reason we are allowed to reduce the size of the service conductor, when the entire load of the house is on those conductors, is because of diversity.
> 
> When you remove certain elements then the diversity disappears.
> 
> Suppose, as in your example, one panel had 190 amps of heating loads. Now you want to use 2/0 but 2/0 is really only good for 175 amps. If all the heat units come on at the same time then you are overloading those conductors, whereas, *if the panel had other types of loads then the calculated load is not likely to ever reach 190 amps.*


 And therein lies the rub. 

First your premise depends on the calculated load being correct, which it never is since it's only a gross approximation. Second, when you say that "_it's not likely_", that means that there are some situations that it will happen. 

So if it's happening in those situations with no ill effect, then that means it's perfectly ok. 2/0 Cu can handle it. So it should be allowed in all situations.

If you don't believe that, then you are essentially saying that it's ok for the houses to burn down in some situations.



> A typically 200 amp panel generally never sees anywhere near 125 or 150 amps


Again, "typically", but not always. So it's unsafe in those non-typical situations? Or is it safe? Which one? It could only be one or the other, not both.

BTW, what was typical yesterday is not tomorrow. With vehicle chargers drawing solid loads for 8-12 hours those 200A panels will be loaded. But it shouldn't matter because the breaker should be sized to protect the conductor, not what some guy _thinks_ the load will be.


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## Dennis Alwon (May 9, 2009)

I agree with most of what you say and I always thought that one day the residential reduction on service conductors will be taken away... I doubt it tho... unless someone could show it is an issue it will be there...

When I do a 400 amp service I usually use 4/0 aluminum because in conduit it is rated 75C and is good for 180 amps. 

That's another rule that should be gone also... 180 amps and I can use a 200 amp breaker as long as the calculated load is 180 amps or less.. What happens afterwards?

Again, unless there are issues with this I doubt it will change. I use that rule time and time again especially with 6/3 nm to a sub panel-- I use a 60 amp breaker. Got called on it once and had to go over the inspectors head.


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## telsa (May 22, 2015)

Arrow3030 said:


> I kinda get what you're saying. Let me rephrase to see if I'm picking it up.
> 
> A single family house has a calc load of 300 amps.
> *The electrician uses a 320 continuous amp meter main* with 2 200 amp service disconnect breakers feeding two 200 amp mlos in the building.
> ...


320A Meters can take 400A all day and all night.

The notion that they can only take 320A is actually false.

The rate is Poco 'code speak' that this is a single-phase Residential-rate Service.

This links back to how the Poco is going to calculate it for their own load calcs -- and how it's going to be rated for billing purposes.

The exact same load going to a Commercial account would be termed a 400A Service and would NOT be permitted to use a Residential meter. You'll find that most Pocos will insist on CTs for such Commercial Services -- even if the load is Single-Phase.

This gets back to the WAY that Commercial accounts load up the Poco grid. They scarcely use ANY power at night -- and then go FULL BORE every morning -- totally lacking in 'diversity.' This trait dictates that the Poco scale up their grid -- all the way.

This is the reason that (small) Commercial accounts don't get Residential rates.

It's for Poco convenience that Residential rated Services use so-called 320A meters. This provides a dreamy public relations explanation to Commercial accounts why they're paying more for juice.

Why, they're getting an extra 80A of capacity ! Heh.

You'll often find that should a Residence really crack the barrier -- and need more power -- suddenly they've lost their Residential rate. They'll be charged Commercial rates. 

The CEO of Intel (Andy Grove) ran 800A 208Y120 to his residence. Did I mention that it was huge... and that he had a laboratory in his 'basement' ? You bet he was paying Commercial rates. 

In sum, 320A meter is a _notional _term. They really can take 400A.

Such meters are the upper limit for Residential rate tariffs. That's why the term is used. It's short-hand for 'Residential rate tariff.'

400A is short-hand for 'Commercial rate tariff.'

BTW, CTs permitted the Poco to re-enter the cabinet and take measures such as time-of-day usage -- long before modern digital gadgets. Such measures were impossible with the old format 320A meters.

This also means that -- push come to shove -- you have to wire such meters as if they're going to draw heavy -- unless you have 'Residential diversity.'

[ ie Folks don't usually turn on every dang load in a house at the same time. -- Commercial accounts are famous for doing exactly that -- no diversity at all. ]

In the OP's case, he can't assure anyone that he'll have 'load diversity' -- so the most conservative engineering standards are invoked.

THIS is what is at the heart of the matter.

The standard is what _might_ happen -- not what is reasonable to the original installer.


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## RePhase277 (Feb 5, 2008)

Dennis Alwon said:


> I agree with most of what you say and I always thought that one day the residential reduction on service conductors will be taken away... I doubt it tho... unless someone could show it is an issue it will be there...
> 
> When I do a 400 amp service I usually use 4/0 aluminum because in conduit it is rated 75C and is good for 180 amps.
> 
> ...


There is some wiggle room built into the ampacities. 4/0 aluminum won't just burst into flames at 181 amps. In fact, I bet it could handle 200 amps all day long, maybe just get a little warmer.


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## HackWork (Oct 2, 2009)

Dennis Alwon said:


> I agree with most of what you say and I always thought that one day the residential reduction on service conductors will be taken away... I doubt it tho... unless someone could show it is an issue it will be there...
> 
> When I do a 400 amp service I usually use 4/0 aluminum because in conduit it is rated 75C and is good for 180 amps.
> 
> That's another rule that should be gone also... 180 amps and I can use a 200 amp breaker as long as the calculated load is 180 amps or less.. What happens afterwards?


 EXACTLY! That's my whole point. 

If that extra 20A difference is actually dangerous, then it should not depend on some guy's estimation of the load. And what if a larger load is added later? 



> Again, unless there are issues with this I doubt it will change.


Oh I agree, I doubt it will change either. 

I don't see us having any issues because the conductor is oversized. 2/0 Cu and 4/0 Al is enough to handle 200A. 3/0 Cu and 250 MCM Al is not necessary.


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## lighterup (Jun 14, 2013)

HackWork said:


> EXACTLY! That's my whole point.
> 
> If that extra 20A difference is actually dangerous, then it should not depend on some guy's estimation of the load. And what if a larger load is added later?
> 
> ...


I can give you a real time example of the "larger load being added later"

3 days ago , I get a call to give an estimate to install power for an
on demand Hot water tank

I headed out there thinking it was gas fire (needing just 
the 120 volt outlet receptacle) cause the guy mentioned 
didn't look like there was any spaces left in his panel.

I get out there...it's an electric heated one calling for 125 amp
OCP...he has a 200 amp service ...booked to the hilt with other
large loads to include electric heat , oven etc...

He wants me to add a sub panel , I'm talking service upgrade.

I get shown the door...says (2) other guys already looked and 
neither mentioned service upgrade....I tell him to keep 911 on 
speed dial (he's out in the boonies ...FD will need as much of a 
head start as possible.


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## HackWork (Oct 2, 2009)

The thing about load calcs is that most electrician don't even know how to do them.

I bet half of this forum, who in generally are way above average electrician, can't do a proper and correct load calc. And I definitely include myself in that, I use the Excel load calculator on Mike Holt's site. If I did a load clac by hand, there would be many mistakes or things that I need to ask about.


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## Arrow3030 (Mar 12, 2014)

HackWork said:


> The thing about load calcs is that most electrician don't even know how to do them.
> 
> I bet half of this forum, who in generally are way above average electrician, can't do a proper and correct load calc. And I definitely include myself in that, I use the Excel load calculator on Mike Holt's site. If I did a load clac by hand, there would be many mistakes or things that I need to ask about.


Inspectors and poco always ask for load calcs out here. I'm in a black market homegrown area if you get me. 

Most electricians I've worked with get all kind of cranky when asked for one. Probably bc they don't even know the difference between FLC and FLA.

I'd like to say that I'm getting better at them but I'm sure I've made plenty of mistakes.


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## lighterup (Jun 14, 2013)

Arrow3030 said:


> Inspectors and poco always ask for load calcs out here. I'm in a black market homegrown area if you get me.
> 
> Most electricians I've worked with get all kind of cranky when asked for one. Probably bc they don't even know the difference between FLC and FLA.
> 
> I'd like to say that I'm getting better at them but I'm sure I've made plenty of mistakes.


not sure why you would say "probably" made mistakes.

Ubless your burning down buildings you're more likely
doing just fine


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## Arrow3030 (Mar 12, 2014)

lighterup said:


> Arrow3030 said:
> 
> 
> > Inspectors and poco always ask for load calcs out here. I'm in a black market homegrown area if you get me.
> ...


 All I know is I can take the same info for the same job, do a calc for it, double check it a week later and have a different number.

I can always find the discrepancy to get matching answers but maybe I made the same mistake twice and didn't catch it.

This really is my main gripe w inspectors and plan checkers. I want my work checked with scrutiny. 

This is also why this site is legit. When someone has a **** answer, it's corrected.


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## frenchelectrican (Mar 15, 2007)

lighterup said:


> I can give you a real time example of the "larger load being added later"
> 
> 3 days ago , I get a call to give an estimate to install power for an
> on demand Hot water tank
> ...



Let those two bakas deal with it and they will get the grist of it quick.,

This unforetally it is kinda common when someone buy a big arse tankless unit and they dont relized the service size need to be upgraded.

I get the same pattern as you posted and I tell them first thing out of my mouth is service upgrade as they get that big arse tankless unit.


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## Wiresmith (Feb 9, 2013)

i believe you all are assuming some things incorrectly. this part of the code is perfectly logical.

you have to remember there are a lot more pages in the book than the one you are reading and they are all related.


-240.4 conductors shall be protected against over-current in accordance with their amapcities. 

-310.15(B)(7) is not raising the ampacity of a conductor, it allows you to not use the full capacity of the service(how much current the utility will provide to you)

- i believe you are confusing branch circuit rating and service rating, branch circuits are rated based on ocpd


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## Wiresmith (Feb 9, 2013)

read blue text on page 262 of handbook

the ocpd is based on the wire amapacity (which is based on the load) not the other way around


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## HackWork (Oct 2, 2009)

hd13 said:


> i believe you all are assuming some things incorrectly. this part of the code is perfectly logical.
> 
> you have to remember there are a lot more pages in the book than the one you are reading and they are all related.
> 
> ...


Your service OCPD isn't sized to what the "utility will provide to you". It's sized to protect the service entrance conductors.

So can 4/0 Al or 2/0 Cu handle 200 or not?


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## HackWork (Oct 2, 2009)

hd13 said:


> read blue text on page 262 of handbook
> 
> the ocpd is based on the wire amapacity (which is based on the load) not the other way around


And the point that some of us are making is that *no one* actually knows what the load is going to be. Someone is going to do a load calculation, which is nothing more than a guess. 

And a load calculation done today means nothing next year, or the year after, or in 50 years when that service is still there. If 4/0 Al can't handle 200A, why protect it with with a 200A breaker? The code allows that if someone says that the load is only 180A or less, but what right does that person have to determine what the load will be?


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## Wiresmith (Feb 9, 2013)

HackWork said:


> Your service OCPD isn't sized to what the "utility will provide to you". It's sized to protect the service entrance conductors.
> 
> So can 4/0 Al or 2/0 Cu handle 200 or not?


you use the tables based on the installs characteristics ( insulation rating, terminal rating, raceway or free air) like a branch circuit conductor.
or under engineering supervision you can do an ampacity calculation(see 310.15(A)(1) for using calculation)


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## Wiresmith (Feb 9, 2013)

HackWork said:


> And the point that some of us are making is that *no one* actually knows what the load is going to be. Someone is going to do a load calculation, which is nothing more than a guess.
> 
> And a load calculation done today means nothing next year, or the year after, or in 50 years when that service is still there. If 4/0 Al can't handle 200A, why protect it with with a 200A breaker? The code allows that if someone says that the load is only 180A or less, but what right does that person have to determine what the load will be?


i agree the calculation is a guess that is why the ocpd is based on the conductor ampacity(which is based on calculated load). if the conductor ampacity is exceeded the ocpd is supposed to open


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## HackWork (Oct 2, 2009)

hd13 said:


> you use the tables based on the installs characteristics ( insulation rating, terminal rating, raceway or free air) like a branch circuit conductor.
> or under engineering supervision you can do an ampacity calculation(see 310.15(A)(1) for using calculation)


Neither of those options apply to this.


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## HackWork (Oct 2, 2009)

hd13 said:


> i agree the calculation is a guess that is why the ocpd is based on the conductor ampacity(which is based on calculated load).


You first say that the calculation is a guess, but then say that it's justified by it being based on the conductor ampacity, which is based on the guess that you first mentioned.

Int he end, it's based on a guess, and the conductors are not being protected.



> if the conductor ampacity is exceeded the ocpd is supposed to open


 This isn't true, and it is the point of contention. The conductor ampacity is 180A yet the breaker is 200A.

There is nothing in the code changing the ampacity of the conductor to 200A. The code is simply allowing you to use a larger breaker if some guy's guess says not a lot of current will flow.


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## Wiresmith (Feb 9, 2013)

-240.4 conductors shall be protected against over-current in accordance with their amapcities in 310.15


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## HackWork (Oct 2, 2009)

hd13 said:


> -240.4 conductors shall be protected against over-current in accordance with their amapcities in 310.15


And in the situation we are speaking about, they are not protected that way.


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## Wiresmith (Feb 9, 2013)

HackWork said:


> And in the situation we are speaking about, they are not protected that way.


i am not completely following what you are saying.

310.15(B)(7) is not allowing you to use a breaker that has a setting higher than the ampacity of the conductor it is protecting, it is allowing you to not use the total capacity of the service and in turn allows you if your not going to use the total capacity to lower the ampacity down to 83% (but not lower than required by calculated load)

the breaker is based on the conductor ampacity not the other way around


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## Wiresmith (Feb 9, 2013)

HackWork said:


> . The code is simply allowing you to use a larger breaker if some guy's guess says not a lot of current will flow.


no its allowing you to use smaller wire down to 83% if the load allows, but the ocpd is based on the wire you use. the wire must be properly protected to limit overcurrent.

if you use smaller wire the ocpd must be sized properly for the wire you chose


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## Wiresmith (Feb 9, 2013)

if you have a 200 amp service you can put a 175A main breaker in

the service is the amount of current the utility you will supply


i believe you may be confusing branch circuit rating which is based on ocpd


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## HackWork (Oct 2, 2009)

hd13 said:


> i am not completely following what you are saying.
> 
> 310.15(B)(7) is not allowing you to use a breaker that has a setting higher than the ampacity of the conductor it is protecting


 It most certainly is allowing that.

4/0 Al has an ampacity of 180 but it allows you to use it protected by a 200A breaker.



> it is allowing you to not use the total capacity of the service


 I disagree. There is nothing limiting how much of the service someone uses (other than the 200A breaker, limiting to 200A) and no one knows how much will actually be used.



> the breaker is based on the conductor ampacity not the other way around


In this situation, the breaker is NOT based on the conductor ampacity.

I will ask again, how is this any different than allowing #14 wire on a 30A breaker for a general outlet circuit as long as someone says the load will be less than 10A?


----------



## HackWork (Oct 2, 2009)

hd13 said:


> the wire must be properly protected to limit overcurrent.


Exactly, but it's not when using 310.15(B)(7)


----------



## HackWork (Oct 2, 2009)

hd13 said:


> if you have a 200 amp service you can put a 175A main breaker in


Provided there's nly 1 main disconnect (not a multi-family dwelling) than that would be a *175A service*. Not a 200A.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> Provided there's nly 1 main disconnect (not a multi-family dwelling) than that would be a *175A service*. Not a 200A.


article 100

service- the conductors and equipment for delivering electric energy from the serving utility to the wiring system of the premises served

its not the main breaker size, the breaker is part of the premises wiring


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> It most certainly is allowing that.
> 
> 
> In this situation, the breaker is NOT based on the conductor ampacity.
> ...


what you are describing is no different, i am saying what you are describing is based on a misunderstanding


----------



## HackWork (Oct 2, 2009)

hd13 said:


> article 100
> 
> service- the conductors and equipment for delivering electric energy from the serving utility to the wiring system of the premises served
> 
> its not the main breaker size, the breaker is part of the premises wiring


You definition doesn't change anything that I said.

When there is 1 main OCPD, the service size is determined by the size of said OCPD.

If you have a split-bus panel or multiple panels, which will have multiple main disconnects, then the service is sized according to the SEC's.


----------



## Wiresmith (Feb 9, 2013)

i will add this for anyone that is sweating, the ocpd the poco has will probably blow when the sec fails, before a fire starts


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> When there is 1 main OCPD, the service size is determined by the size of said OCPD.
> 
> .


i believe you are confusing branch circuit ratings which are based on the ocpd


----------



## HackWork (Oct 2, 2009)

hd13 said:


> what you are describing is no different, i am saying what you are describing is based on a misunderstanding


There is no misunderstanding.

When using 310.15(B)(7), you are not sizing the OCPD to the conductor's ampacity, you are sizing the conductors to a guesstimate that some random guy made. And by doing such, you are allowing more current on those conductors than the NEC says they can handle.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> i will add this for anyone that is sweating, the ocpd the poco has will probably blow when the sec fails, before a fire starts


This is another fallacy. It's simply not true. 

With all due respect, by saying this, you show that you have very little experience in this realm.


----------



## Wiresmith (Feb 9, 2013)

you can have a 175 amp breaker on your service disconnecting means and have a 200 amp service to the premises. the capacity of the premises wiring is limited by the 175 amp breaker but you have a 200 amp service


----------



## HackWork (Oct 2, 2009)

hd13 said:


> i believe you are confusing branch circuit ratings which are based on the ocpd


No matter how many times you say that, it won't make it true.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> There is no misunderstanding.
> 
> When using 310.15(B)(7), you are not sizing the OCPD to the conductor's ampacity, you are sizing the conductors to a guesstimate that some random guy made. And by doing such, you are allowing more current on those conductors than the NEC says they can handle.


partially correct

310.15(B)(7) is sizing the conductors BUT proper ocpd must be provided for the conductor, its thinking backwards than we normally do(20 amp circuit so i gotta pull #12)


----------



## HackWork (Oct 2, 2009)

hd13 said:


> you can have a 175 amp breaker on your service disconnecting means and have a 200 amp service to the premises.


 No, you can't. Not if that 175A breaker is the sole main disconnect, like we are talking about in this thread.



> the capacity of the premises wiring is limited by the 175 amp breaker but you have a 200 amp service


No, you don't. You have a 175A service.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> No matter how many times you say that, it won't make it true.


i believe its what's messing you and tons of others up


----------



## HackWork (Oct 2, 2009)

hd13 said:


> 310.15(B)(7) is sizing the conductors BUT proper ocpd must be provided for the conductor


 But it's not. The _proper OCPD_ for 4/0 would be *180A*. But that section is allowing you to use a 200A breaker.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> No, you can't. Not if that 175A breaker is the sole main disconnect, like we are talking about in this thread.
> 
> 
> 
> No, you don't. You have a 175A service.


your capacity is limited by you to 175A but the poco is giving you a 200 amp service


----------



## HackWork (Oct 2, 2009)

hd13 said:


> i believe its what's messing you and tons of others up


It's not. And yet again you have chosen to go against something that everyone else understands and tell us that we are all wrong. 

I think, before doing that, you should find out how PoCo cut-outs work and how to properly determine the service size when there is 1 main disconnect.

Have a good day :smile:


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> This is another fallacy. It's simply not true.
> 
> With all due respect, by saying this, you show that you have very little experience in this realm.


i have almost no experience in residential wiring.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> your capacity is limited by you to 175A but the poco is giving you a 200 amp service


Wow, just wow...



hd13 said:


> i have almost no experience in residential wiring.


That fact is very. very clear.

But you have no problem preaching all this nonsense about it...

Good bye


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> It's not. And yet again you have chosen to go against something that everyone else understands and tell us that we are all wrong.
> 
> I think, before doing that, you should find out how PoCo cut-outs work and how to properly determine the service size when there is 1 main disconnect.
> 
> Have a good day :smile:


i have more experience installing cut-outs than romex


----------



## Wiresmith (Feb 9, 2013)

i'm sorry your taking offense to this, but please give what i am saying a second thought


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> It's not. And yet again you have chosen to go against something that everyone else understands and tell us that we are all wrong.
> 
> 
> Have a good day :smile:



i got lucky and learned to double check the bull**** my journeymen were teaching me early on


----------



## Arrow3030 (Mar 12, 2014)

I'd probably be more into this if I was involved from the start of the conversation. 

HD, I'm really not following where my misunderstanding is.

310 is an estimation of how hot conductors will get based on their size, load and condition of use. 

B7 is a very specific condition of use that for some reason is either allowing the conductor to get hotter than "normal" or is allowing the calculated load to be corrected and lowered.

My guess of those two options is the latter.


----------



## HackWork (Oct 2, 2009)

All this doesn't matter because the power company turns on the hose to 200A. Anything more and their cut-outs will blow!


----------



## Wiresmith (Feb 9, 2013)

Arrow3030 said:


> I'd probably be more into this if I was involved from the start of the conversation.
> 
> HD, I'm really not following where my misunderstanding is.
> 
> ...


-it is allowing you to not have to use wires sized for the full ampacity of the service(not service disconect ocpd setting, but the current the poco will supply), if the calculated load is low enough

-the wire still has to be big enough for the load and the ocpd setting has to be low enough to protect the conductor from overload

-the wire determines the ocpd not the other way around. (and the load determines the wire size)


----------



## Wiresmith (Feb 9, 2013)

don't confuse the fact that branch circuit rating is based on your ocpd and that your main breaker is the service rating, its not like that

service is what the utility provides


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> All this doesn't matter because the power company turns on the hose to 200A. Anything more and their cut-outs will blow!


except for when neighbors share cut-outs


----------



## Wiresmith (Feb 9, 2013)

this ones not making it to 1,000


----------



## lighterup (Jun 14, 2013)

Question:

The discussion is on SEC's and service OCPD.

I've red the posts from all above.

In the city , most services are over head. Most of 
which remain #2 sized messenger wire with the
steel
bare cable that is the neytral.

we are discussing if 180 -200 amps passing thru 4/0
urd ..._"will the conductor be okay past 180 amps"_
has been brought up.

what I'd like to know is , other then being in open air , 
how can that #2 messenger wire handle this type of load
thus why even worry about 4/0 AL?


----------



## HackWork (Oct 2, 2009)

lighterup said:


> Question:
> 
> The discussion is on SEC's and service OCPD.
> 
> ...


The heat is allowed to radiate off of it. Even if it gets red hot, what's the worst that can happen?

If your service entrance conductors get hot, they could burn down the house.

FWIW, around here they also use #2 for the hot conductors in the overhead line as well, not just the neutral. But that is only on newer lines, I have seen some old ones with #6's.


----------



## Wiresmith (Feb 9, 2013)

being in free air it can dissipate the heat very easily, jackets and raceways insulate the conductors like insulation in the walls of your house


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> FWIW, around here they also use #2 for the hot conductors in the overhead line as well, not just the neutral. But that is only on newer lines, I have seen some old ones with #6's.


#2 aluminum #6 copper for 100A?


----------



## Wiresmith (Feb 9, 2013)

lighterup

remember current rating is based on the temperature the conductor insulation can withstand, it is the weaker link and the wire operating temperature is based on the current and how easily the conductor assembly can get rid of the heat

and also remember to take into consideration your terminations temperature ratings which you cannot exceed(ESPECIALLY WITH ALUMINUM)

the tables read in current but they are based on temperature at that current with that insulation and situation, those tables are actually using a wire length as well


----------



## Wiresmith (Feb 9, 2013)

lighterup said:


> Question:
> 
> 
> what I'd like to know is , other then being in open air ,
> ...


table 310.5(B)(20) free air #2 aluminum is good for 106-123 amps depending on insulation (100 amp services?)


----------



## frenchelectrican (Mar 15, 2007)

hd13 said:


> #2 aluminum #6 copper for 100A?


Ya for POCO drop or laterals .,

Yes I have see it over here as well and it is very common over here too.

I have see alot of #2 al drop with 100 and 200 amp service and the POCO conductors have diffrent rating on their conductors. 

#6 CU ? some area yuh but yes I have see #6 *Al* drops for 100 amp service and they handle it pretty good.

Now ya mention POCO cut off .,, in North America side the POCO is typically sized the OCPD way above the transfomer rating which I have it it often but here in my location they sized little more closer to the transfomer rating but yes it still above the transfomer due they can handle alot of overload for a quite a while.

If you ever see the service drop shorted out ? the resdentail drop or light commercal drops the service drop conductors will keep shorting until the transfomer OCPD drop out ( some case it did not kick out espcally with larger transfomer with light load ) but well loaded transfomer yes it can kick out quicker.


----------



## lighterup (Jun 14, 2013)

I would say the bulk majority of electrical services I've done
in residential (3 wire Edison) 200 amp services. Tons of them.
of which most % of those I used 4/0 ALURD ...cut & dry

some of those 250cm or a few 350cm strictly cause
of compensating for very long distances on the secondaries.

I have not ever encountered any problems with this issue.

I do agree that the demand factor is a rough guess 
cause we don not know what future loads will be brought into
the scenario after we are gone from the job.


----------



## Wiresmith (Feb 9, 2013)

you sure the #6 al aren't for the old 60 amp services


----------



## lighterup (Jun 14, 2013)

hd13 said:


> table 310.5(B)(20) free air #2 aluminum is good for 106-123 amps depending on insulation (100 amp services?)


also average ambient air temperauture

example here in Ohio vs Nevada? more than likely different
capabilities


----------



## frenchelectrican (Mar 15, 2007)

hd13 said:


> table 310.5(B)(20) free air #2 aluminum is good for 106-123 amps depending on insulation (100 amp services?)


I hate to tap on your shoulder but can ya clearify it little more on the table 310.5 ? which type of conductor insluationg and type what you are refering to .? The SE or SER or XLPE or others ?


----------



## Wiresmith (Feb 9, 2013)

nevermind table 310.15(B)(21) does allow #6 al to 101 amps


----------



## frenchelectrican (Mar 15, 2007)

hd13 said:


> you sure the #6 al aren't for the old 60 amp services


If ya going from 60 to 100 amp service most case the POCO dont bother change the #6 service drop at all unless it was cracking bad or other type of damage show up on it.


----------



## Wiresmith (Feb 9, 2013)

frenchelectrican said:


> I hate to tap on your shoulder but can ya clearify it little more on the table 310.5 ? which type of conductor insluationg and type what you are refering to .? The SE or SER or XLPE or others ?


that's why i put the current range, i'm not talking about a specific insulation the range covers all of them in the table


----------



## Wiresmith (Feb 9, 2013)

frenchelectrican said:


> If ya going from 60 to 100 amp service most case the POCO dont bother change the #6 service drop at all unless it was cracking bad or other type of damage show up on it.


never-mind table 310.15(B)(21) does allow #6 al to 101 amps


----------



## Wiresmith (Feb 9, 2013)

i'm needing to get off here, i'll check back in another day. thanks for not lynching me, i'm honestly just trying to help.


----------



## frenchelectrican (Mar 15, 2007)

hd13 said:


> that's why i put the current range, i'm not talking about a specific insulation the range covers all of them in the table


Fair enough on that.


----------



## Arrow3030 (Mar 12, 2014)

@hd13, I still don't understand what you're trying to explain. Can you say it in a different way?


----------



## Wiresmith (Feb 9, 2013)

Arrow3030 said:


> @hd13, I still don't understand what you're trying to explain. Can you say it in a different way?


yes, if your messing with me i'm gonna be mad. let me think for a minute. whats your understanding or what part do you think your not understanding?

please give me some feed back to see what your thinking on the subject


----------



## Wiresmith (Feb 9, 2013)

310.15(B)(7) is not allowing you to use an ocpd(breaker/fuse) with a setting above the ampacity(given in 310.15 tables based on the particular situation(free air/raceway etc)) of the conductor used, just like you would size ocpd for a #6 branch circuit.


-you do your load calc
-your service must be big enough for load
-your conductors have to be big enough for the load
-your conductors must have ocpd protection for overload based on the tables alone. 310.15(B)(7) has nothing to do with this


-310.15(b)(7) allows you to use wires smaller than the ampacity of the service( but still large enough for load)

-ocpd setting is determined by the wire you use not the service size, the ocpd must have a setting that will limit the over-current on the conductors to there allowable ampacity


these code panel guys aren't complete dumbass'

burning houses down is bad for anyone that can be associated with it, including them


----------



## HackWork (Oct 2, 2009)

hd13 said:


> table 310.5(B)(20) free air #2 aluminum is good for 106-123 amps depending on insulation (100 amp services?)


Utilities don’t use the NEC. You really need to step away and stop giving all this bad information.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> Utilities don’t use the NEC. You really need to step away and stop giving all this bad information.


the insulation burns off at the same temperature whether in a house or on the pocos pole


----------



## HackWork (Oct 2, 2009)

hd13 said:


> the insulation burns off at the same temperature whether in a house or on the pocos pole


The tables that the PoCo uses allow a much higher ampacity.

This is what, the fourth thing that you posted in this thread that is completely wrong?

Like I said, just stop.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> The tables that the PoCo uses allow a much higher ampacity.


prove it


----------



## Wiresmith (Feb 9, 2013)

i'm not telling anyone to take my word for anything that's why i cite my sources


----------



## Wiresmith (Feb 9, 2013)

im out for now


----------



## telsa (May 22, 2015)

To the OP.

What's the battle ?

If you qualify, you get to use the reduced conductors.

If you don't qualify you don't get to used the 83% rule.

Stop worrying about it.

There is no money to be made working down this trail.

You go to 100% and move on to your next project.

Lay the extra expense off to the customer.

Done.

&&&

Worrying about this or that line item of expense is NOT how you make it our trade.

Speed and elegance of installation is how you make it. :biggrin:

Get it ? :smile:

Trying to re-engineer things against the NEC because you 'know better' is the route to madness.

Most of the weird provisions in the NEC exist because of complications that no-one saw coming -- were discovered the HARD way.

You can't afford to 'discover' those lessons all over again.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> prove it


You want me to prove that the power companies use the NESC along with their own engineers recommendations to size their overhead lines, something that everyone else knows?

Why? Why don’t you just educate yourself before spewing all this misinformation?


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> "Originally Posted by hd13 View Post
> the insulation burns off at the same temperature whether in a house or on the pocos pole"
> 
> The tables that the PoCo uses allow a much higher ampacity.
> ...


you think an insulation melts at a different temperature depending on who owns it?


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> You want me to prove that the power companies use the NESC along with their own engineers recommendations to size their overhead lines, something that everyone else knows?
> 
> Why? Why don’t you just educate yourself before spewing all this misinformation?


"The National Electrical Safety Code (NESC) only addresses conductor ampacity directly relative to grounding conductors."
excerpt from https://iaeimagazine.org/magazine/2004/03/16/conductor-ampacity/


the nec also allows engineering to determine ampacity and not use the tables, genius, you can hire an engineer and do that 310.15(C)(1)


----------



## HackWork (Oct 2, 2009)

I did not say a word about insulation melting off.

I said that you should not be posting a table from the NEC when talking about power company’s overhead line ampacity.

I think it’s clear how foolish your posts are and will not be replying to you any longer.


----------



## Wiresmith (Feb 9, 2013)

*310.15(c)*


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> I did not say a word about insulation melting off.
> 
> I said that you should not be posting a table from the NEC when talking about power company’s overhead line ampacity.
> 
> I think it’s clear how foolish your posts are and will not be replying to you any longer.


i said it and you said i was completely wrong about it


----------



## Wiresmith (Feb 9, 2013)

arrow, what are you thinking?


----------



## HackWork (Oct 2, 2009)

hd13 said:


> "The National Electrical Safety Code (NESC) only addresses conductor ampacity directly relative to grounding conductors."
> excerpt from https://iaeimagazine.org/magazine/2004/03/16/conductor-ampacity/
> 
> 
> the nec also allows engineering to determine ampacity and not use the tables, genius, you can hire an engineer and do that 310.15(C)(1)


You called me a genus in a sarcastic way, but your posts don't make any sense.

1) You post an NEC table when discussing the ampacity of the power company's overhead lines.
2) I explained to you how that doesn't apply because the PoCo doesn't use the NEC, and went on to say that the PoCo uses the NESC as well as their engineers.
3) You try to counter what I said by saying that the NEC will allow engineers to determine ampacity???

And then you are so arrogant and indignant that you post the NEC code article again in another post.

The NEC allowing an engineer to determine ampacities has NOTHING to do with the fact that the PoCo doesn't use the NEC to size their overhead lines. I don't know why you would even post that. You clearly have no understanding of what's going on here, and are just posting bologna.

Everything that you have said in this thread has been completely off base and pretty much the exact opposite of the truth.

-Power companies don't just "give people 200A" because someone calls it a 200A service.
-Cut-outs don't blow when more than 180A is drawn.
-Power company's overhead lines are not sized according to the NEC.
-If a service has a single 175A main breaker, it is a 175A service.
-310.15(B)(7) will allow more current to flow thru service conductors than the NEC lists as their ampacity.

You have said the opposite on all of them.

But I will give you credit, you keep drawing me back in, which I know you are purposely doing with these horribly ignorant posts of yours.


----------



## readydave8 (Sep 20, 2009)

hd13 said:


> i will add this for anyone that is sweating, the ocpd the poco has will probably blow when the sec fails, before a fire starts


I do not believe this to be even a little bit true


----------



## HackWork (Oct 2, 2009)

readydave8 said:


> I do not believe this to be even a little bit true


No, it is, he knows because he works on cut-outs.


----------



## Dennis Alwon (May 9, 2009)

hd13 said:


> prove it


There is nothing to prove. Just look at the size wire they run compared to the wire sizes we use. There's the proof. They know what works for them and that's all they need to worry about.


----------



## telsa (May 22, 2015)

The Poco runs a ton of wire in free air.

That's a whole different kettle of fish.

Power losses due to impedance are charged to the rate-payers.

As are the capital costs involved in the Poco distribution system.

This is the balance that the Poco jockeys around with.

That plus the distances -- the amazing amount of wire they need -- have quite a bearing on their calculations.

Our work needs to be bullet proof... as it's 'maintained' by the common man -- and even worse -- the common handy man.


----------



## lighterup (Jun 14, 2013)

hd13 said:


> you sure the #6 al aren't for the old 60 amp services


I've seen these where old fuse boxes were the only mains 
with (2) 60 amp buss fuses and maybe another set of fuses 
for an electric range...the rest being 120 volt fuses

Very common here in older bungalos built after WWII


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> arrow, what are you thinking?


That Canadian chick doing freestyle moguls is good looking.

Honestly HD, I tried to find some value from when all this started and couldn't really figure out what the point was.

I'm not saying you don't have a point, even though I can't see it, or that you should stop trying to get it across. But for now, I'm done trying to learn something from this thread.


----------



## lighterup (Jun 14, 2013)

For what it's worth

A friend of mine worked for a municipal power company
in NE Ohio for 30+ years as a linesman and then later
as a supervisor before he retired.

He once told me that when we (EC's upgrade or put in new
electrical services such as 200 amp resi) they do not really
do much in the way of upgrading their end (size of overheads)
because they as a plant can only put out so much voltage.

If they HAD to upgrade their end and constantly keep up
with all of these smaller changes , their engineers would
have to constantly re engineer all their sectors and their just
not going to do that.

They do this only when significant changes happen like
urban sprawl...a new housing or commercial development goes
up. That they take seriously


----------



## HackWork (Oct 2, 2009)

Arrow3030 said:


> That Canadian chick doing freestyle moguls is good looking.
> 
> Honestly HD, I tried to find some value from when all this started and couldn't really figure out what the point was.
> 
> I'm not saying you don't have a point, even though I can't see it, or that you should stop trying to get it across. But for now, I'm done trying to learn something from this thread.


What you can take from this is that the NEC makes you oversize conductors quite a bit. It’s says that 4/0 can only handle 180A but we know that it can easily handle 200A and 300.15(B)(7) proves that.


----------



## telsa (May 22, 2015)

lighterup said:


> For what it's worth
> 
> A friend of mine worked for a municipal power company
> in NE Ohio for 30+ years as a linesman and then later
> ...


Yes, but the Pocos do design in a certain level of reserve when they do any design.

They are limited in just how over-engineered they are can go -- by the PUC.

Yes, they have to justify to the government that they are not wasting capital or energy.

The PUC second guesses the Poco all day long. They live for it. :biggrin:

One thing folks seem to forget: all transformers built in North America are so conservatively designed that they can run in overload for hours on end.

THIS is how the Poco is able to 'get on by.'

Every now and then, they get 'bit' -- but not so often it's a problem. ( it takes a heat wave )


----------



## HackWork (Oct 2, 2009)

Wait until electric cars get more popular...

The PoCos will be wishing that they had been upgrading all these years.


----------



## telsa (May 22, 2015)

HackWork said:


> Wait until electric cars get more popular...
> 
> The PoCos will be wishing that they had been upgrading all these years.


It's already been solved : digitally activated kill switches on specific loads.

My home has just such devices on my air conditioning condensors.

PG & E can kill my air conditioning -- at their whim.

The same gambit will surely be introduced for EV charging circuits.


----------



## Arrow3030 (Mar 12, 2014)

HackWork said:


> What you can take from this is that the NEC makes you oversize conductors quite a bit. It’s says that 4/0 can only handle 180A but we know that it can easily handle 200A and 300.15(B)(7) proves that.


Well sure. I already knew that though. I didn't start getting confused until someone told me I was confused...


----------



## HackWork (Oct 2, 2009)

Arrow3030 said:


> Well sure. I already knew that though. I didn't start getting confused until someone told me I was confused...


:vs_laugh: :biggrin:


----------



## HackWork (Oct 2, 2009)

telsa said:


> It's already been solved : digitally activated kill switches on specific loads.
> 
> My home has just such devices on my air conditioning condensors.
> 
> ...


You should move to America.


----------



## emtnut (Mar 1, 2015)

hd13 said:


> #2 aluminum #6 copper for 100A?


#2 AL is good for up to 184A. That's a maximum, assuming 184A 24hrs/day 7 days/week.
POCO will leave #2 ACSR for 200A anyday :biggrin:

And it doesn't melt the insulation


----------



## brian john (Mar 11, 2007)

telsa said:


> It's already been solved : digitally activated kill switches on specific loads.
> 
> My home has just such devices on my air conditioning condensors.
> 
> ...


Voluntarily or forced down your throat in typical Cal. fashion?


----------



## RePhase277 (Feb 5, 2008)

No one ever thinks about the wires as actually being heat sinks, but they are. They wick heat away from device terminals and help keep things cool. Conductors in free air dissipate heat much easier than conductors in pipe, dirt, or walls. And each infinitesimal slice of conductor is a heat sink for each infinitesimal slice of conductor downstream of it. 

I was once in charge of keeping the power on to an outdoor concert that had been very badly under-wired. I know this: #14 UF cable can carry over 90 amps.... once you toss a large enough portion of it into the nearby lake. Reduce the load you say? Well, don't nobody turn down Lucille when BB King is at work!


----------



## telsa (May 22, 2015)

brian john said:


> Voluntarily or forced down your throat in typical Cal. fashion?


Well, MAFIA style, yes. :smile:

Plan B was that PG & E would cut off the entire neighborhood if you ( collectively ) didn't sign up for the program.

Trust me... this is going to be exported to the rest of the nation.

It'll be termed:* Smart Grid.*


----------



## HackWork (Oct 2, 2009)

telsa said:


> Well, MAFIA style, yes. :smile:
> 
> Plan B was that PG & E would cut off the entire neighborhood if you ( collectively ) didn't sign up for the program.
> 
> ...


We don’t follow silly California, thankfully.

They will upgrade the grid as needed in order to keep their cash registers spinning.


----------



## RePhase277 (Feb 5, 2008)

You'll either connect to the available utilities or you'll vacate the premises in many municipalities, apparently.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> You called me a genus in a sarcastic way, but your posts don't make any sense.
> 
> 
> 
> But I will give you credit, you keep drawing me back in, which I know you are purposely doing with these horribly ignorant posts of yours.



your not listening, what your saying i'm saying is not what i'm saying



do you have a 17' code handbook?
page 262 blue text

"the main service or feeder to a dwelling unit is permitted to be sized at 83 percent of the disconnect rating. the calculation is not based on the rating of the overcurrent device protecting the main feeder."

disconnect rating, not your ocpd setting 


310.15(B)(7) is not talking about changing the ampacity of a 4/0(i.e.), its changing the ampacity requirement for the conductors on a 200 amp(i.e.) service

look at 2011 310.15(B)(7) table it does not say those are ampacities for those wires, it is saying that is the minimum wire for that service.

240.4 protection of conductors
conductors shall be protected against overcurrent in accordance with their ampacities in 310.15


230.90(services) each ungrounded service conductor shall have overload protection.


110.14(C) temperature limits
temperature rating associated with the ampacity of a conductor shall be selected and coordinated so as not to exceed the lowest temperature rating of any connected termination, conductor or device.


----------



## HackWork (Oct 2, 2009)

What?


----------



## lighterup (Jun 14, 2013)

HackWork said:


> What?


He's saying the main breaker is not the disconnect rating


----------



## Wiresmith (Feb 9, 2013)

readydave8 said:


> I do not believe this to be even a little bit true


that's why i said probably, hopefully the cable will fail producing a large enough short circuit to open the ocpd before the structure ignites


----------



## HackWork (Oct 2, 2009)

Wow, lol...


----------



## lighterup (Jun 14, 2013)

I'm getting confused about this , so I'll stick with what
I have done and what I know other decent electricians have done.


----------



## readydave8 (Sep 20, 2009)

hd13 said:


> that's why i said probably


yeah and I said probably not


----------



## jhil302 (Sep 26, 2015)

So I have a question related to the original reason of this thread. I use 320/400 meter bases regularly to feed a residence with one 200 amp disco and feed a 
separate shop/barn building with sometimes 200 amp or 100 amp disco. This is in a rural setting and meter and discos are on pole or strut remote from the buildings they are feeding . I size my service feed conductors to the separate structures based on the 83% rule, so is this wrong? I thought since each feeder carried the entire load of that particular structure, it was ok.


----------



## Arrow3030 (Mar 12, 2014)

Your interpretation sounds correct to me.

If the 400 had distribution other than the two feeders there would most likely be a violation.


----------



## Wiresmith (Feb 9, 2013)

jhil302 said:


> So I have a question related to the original reason of this thread. I use 320/400 meter bases regularly to feed a residence with one 200 amp disco and feed a
> separate shop/barn building with sometimes 200 amp or 100 amp disco. This is in a rural setting and meter and discos are on pole or strut remote from the buildings they are feeding . I size my service feed conductors to the separate structures based on the 83% rule, so is this wrong? I thought since each feeder carried the entire load of that particular structure, it was ok.



-the feeders to the separate shops are not service's if your "one 200 amp disco" disconnects it

-the 83% rule is for dwelling's, somewhere it might say dwellings include related structures but i'm not finding it, all im finding is article 100 definition, which i think excludes shops related to a dwelling unit.

-you didn't say anything about what size ocpd is on your feeder to your shop, but because of what your talking about i want to make sure you know that your ocpd has to be sized properly for your wire for its ampacity (table 310.15(B)(16) or whatever) the 83% rule does not raise the ampacity of any wire

-the way i read your post, i don't have enough information to know if it is wrong or right, what size ocpd is on the feeder to the shop and what conductors and wiring method did you use? is the feeder large enough for the load? is the service large enough for all the loads?


----------



## Dennis Alwon (May 9, 2009)

In my opinion you could size the 200 amp conductors to the dwelling at 83% but you cannot size the conductors to the separate structure at 83% since it is not a dwelling. 

For your info, the conductors to the dwelling and structure are feeders , nor service conductors


----------



## HackWork (Oct 2, 2009)

I agree, Dennis. 

When you run a circuit out to a lamppost or a generator or a shed, that doesn't negate the ability to use 310.15(B)(7) to size the SEC's for the house feeding those things.


----------



## Arrow3030 (Mar 12, 2014)

Dennis Alwon said:


> In my opinion you could size the 200 amp conductors to the dwelling at 83% but you cannot size the conductors to the separate structure at 83% since it is not a dwelling.
> 
> For your info, the conductors to the dwelling and structure are feeders , nor service conductors


This makes sense. For some reason I didn't catch that the barn isn't a dwelling.


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> -you didn't say anything about what size ocpd is on your feeder to your shop, but because of what your talking about i want to make sure you know that your ocpd has to be sized properly for your wire for its ampacity (table 310.15(B)(16) or whatever) the 83% rule does not raise the ampacity of any wire


I'm going to try to go down this rabbit hole one more time. Realize I mean no harm, I only want to understand what you're getting at.

Let's try an example HD.
Two questions.

For a 200 amp service for a dwelling where the service supplies power to the entire structure, what is the smallest size ungrounded conductor permitted per 2014/17 NEC?

Second question is identical but it's a 100 amp service this time.


----------



## Wiresmith (Feb 9, 2013)

200a 75 degree connectors 4/0 aluminum
2/0 copper

100a 75 deg. 2 aluminum
4 copper


as long as calculated load is below those ampacities


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> 200a 75 degree connectors 4/0 aluminum
> 2/0 copper
> 
> 100a 75 deg. 2 aluminum
> 4 copper


That makes sense, how did you get those answers?


----------



## Wiresmith (Feb 9, 2013)

200a service 75 deg. connectors 4/0 aluminum maximum ocpd in series(including downstream) with service(often main breaker) is 180a (you will probably only find 175a)


100a 75deg #2 aluminum max ocpd in series (including downstream) with service 90a


----------



## Wiresmith (Feb 9, 2013)

Arrow3030 said:


> That makes sense, how did you get those answers?


83% of 200= 166a

100=83a

wire has to have at least that ampacity

and the structure must have a calculated load less than or equal to those ampacities


----------



## sbrn33 (Mar 15, 2007)

I always rounded my 4/0 aluminum up to 200 no matter where it is. Never had any inspector troubles.


----------



## Wiresmith (Feb 9, 2013)

where we are not on the same page is 230.90 (a)(service ocpd, ungrounded conductor) each ungrounded service conductor shall have overload protection. such protection shall be provided by ocpd in series with service conductor that has a rating NOT higher than the ampacity of the CONDUCTOR(not service)


310.15(B)(7) allows you to use smaller service conductors, but your ocpd is sized based on the wire size.

notice 230.90 says ocpd in series, not like a branch circuit

article 100
branch circuit- the conductors between final ocpd and the outlet

the 83% is for where your building does not require the entire service ampacity and they only make services in so many sizes


----------



## Wiresmith (Feb 9, 2013)

thanks for asking again


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> 200a service 75 deg. connectors 4/0 aluminum maximum ocpd downstream from service(often main breaker) is 180a (you will probably only find 175a)
> 
> 
> 100a 75deg #2 aluminum max ocpd downstream from service 90a


I see. The service conductors are rated 200 amps for this condition of use but the OCPD can't be larger than 180 amps. That would be a 180 amp service though dude.


----------



## HackWork (Oct 2, 2009)

Arrow3030 said:


> I see. The service conductors are rated 200 amps for this condition of use but the OCPD can't be larger than 180 amps. That would be a 180 amp service though dude.


I tried to explain it to him 20 times, but he just won’t listen.

When there is a single OCPD main disconnect for a building, that OCPD size is the service size. That’s all there is to it.


----------



## Wiresmith (Feb 9, 2013)

Arrow3030 said:


> I see. The service conductors are rated 200 amps for this condition of use but the OCPD can't be larger than 180 amps. That would be a 180 amp service though dude.


the ampacity of the service is limited by you to 180, you may actually be able to use a smaller breaker than that as long as the calculated load is covered, but your wires cannot go lower than 83%


your disconnect must be at least 100amp though (be able to open while operating at 100 amp, not ocpd)and not less than calculated load


----------



## Wiresmith (Feb 9, 2013)

2017 nec handbook 310.15(B)(7) explanatory material in handbook


"...the calculation is not based on the rating of the ocpd protecting the main feeder..."


----------



## HackWork (Oct 2, 2009)

The handbook is meaningless, just an opinion.

Plus, we are not talking about calculations.

The service size is the size of the OCPD of the main disco.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> The handbook is meaningless, just an opinion.
> 
> Plus, we are not talking about calculations.
> 
> The service size is the size of the OCPD of the main disco.


by calculations it means when using the 83%(that calculation) (the one we are talking about)

2017 nec handbook 310.15(B)(7) explanatory material in handbook

"...the calculation is not based on the rating of the ocpd protecting the main feeder..."
this text is only for 310.15(B)(7) (the 83% rule)


----------



## Arrow3030 (Mar 12, 2014)

HackWork said:


> I tried to explain it to him 20 times, but he just won’t listen.
> 
> When there is a single OCPD main disconnect for a building, that OCPD size is the service size. That’s all there is to it.


I fully agree with this. It's the way I've always understood it. Hopefully HD has learned something here.

Either way I'm glad to at least finally understand what his point is although it's incorrect.

I'm going to try to get out of this rabbit hole now.


----------



## HackWork (Oct 2, 2009)

Me too, no use wasting more time. He just won’t listen.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> The handbook is meaningless, just an opinion.


i think the different colors for articles makes it easier to find stuff, i highlighted the titles when i only had the nec i dont with the handbook. i also like the pictures and explanatory material especially with new codes. but the price is a shocker when you go to buy your first one,

my thought is buy a handbook every couple of code cycles depending on the type of work im doing and just buy standard nec the other times


----------



## Wiresmith (Feb 9, 2013)

sorry, have a good one


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> sorry, have a good one


It's all good on my end. I'll try to explain how I'm a student of electrical.

The first code book I read all the way through was a handbook. I still appreciate it. After reading it I thought I knew everything.

Then I watched some Holt videos and realized I know nothing and learned from them.

Then I became active in this forum and got humble smacked around. I still do .

It's still important for me to read the code, take my CEU's seriously and watch trade seminars.

By far the best resource for me is this forum along with fact checking info taken from it.

It can be tough to realize you're wrong but letting the guard down and realizing the harsh truth is extremely helpful will only strengthen all of our understanding of the true intent of the code.


----------



## Wiresmith (Feb 9, 2013)

Arrow3030 said:


> It's all good on my end. I'll try to explain how I'm a student of electrical.
> 
> The first code book I read all the way through was a handbook. I still appreciate it. After reading it I thought I knew everything.
> 
> ...


we found something we agree on



i'm learning too,

but i'm confident 310.15(B)(7) does not change the ampacity of a 75 degree 4/0 aluminum

i learn a lot from this forum


----------



## sbrn33 (Mar 15, 2007)

jhil302 said:


> So I have a question related to the original reason of this thread. I use 320/400 meter bases regularly to feed a residence with one 200 amp disco and feed a
> separate shop/barn building with sometimes 200 amp or 100 amp disco. This is in a rural setting and meter and discos are on pole or strut remote from the buildings they are feeding . I size my service feed conductors to the separate structures based on the 83% rule, so is this wrong? I thought since each feeder carried the entire load of that particular structure, it was ok.


I am not sure if you need a disco out there. then you could use the exception. Same structure you would need one but separate not so much.


----------



## Wiresmith (Feb 9, 2013)

sbrn33 said:


> I am not sure if you need a disco out there. then you could use the exception. Same structure you would need one but separate not so much.


225.31 & 225.32
disco must be nearest point of entrance of conductors, inside or out


but he can go lower ampacity than a dwelling

just has to cover calculated load
and cover conductors with proper ocpd


----------



## Wiresmith (Feb 9, 2013)

and 240.21(B)(5) unlimited tap length

as long as he complies with requirements he only needs the ocpd at the building he is feeding


i'm refering this to re-iterate the way the code looks at service conductors
you have ocpd for your service conductors(main breaker or whatever) (SERIES)(you gotta get out of the branch circuit mindset)


----------



## Wiresmith (Feb 9, 2013)

p.s. i will not call anyone a hack or say someone is not meeting the industry standard(actual standard not nec) if they overrate there service conductors using the 83% because they don't share in the way i read the code. i'm just telling you this because i believe it is being used incorrectly, and i believe if it were used correctly by more people we would have better electrical installations(that actually meet the nec minimum requirements). there are many things taught wrong in our industry, i don't blame people for not knowing everything, i just try to help them understand and hope someone will do the same for me.


----------



## Arrow3030 (Mar 12, 2014)

I can't tell if you're a clown on purpose.

You do realize a 20 amp breaker on a 200 amp bus is a tap rule hiding from you right? It's still in series which seems to be important to you.


----------



## Wiresmith (Feb 9, 2013)

Arrow3030 said:


> I can't tell if you're a clown on purpose.
> 
> You do realize a 20 amp breaker on a 200 amp bus is a tap rule hiding from you right? It's still in series which seems to be important to you.


that's not using the tap rule

tap rule is ocpd downstream from conductor it is protecting


besides the tap conductors for a device (which i've never heard referenced as part of the "tap rule")

im not trying to be a clown in this thread, its a lot later here than it is there


----------



## Dennis Alwon (May 9, 2009)

hd13 said:


> but i'm confident 310.15(B)(7) does not change the ampacity of a 75 degree 4/0 aluminum
> 
> i learn a lot from this forum


In a sense it does. The 83% rule assumes that with a service calculated at 200 amps one will probably never see more than 166 amps however in the rare case that it may go beyond the 180 amps of the aluminum conductor(4/0) or 175 amps of the copper conductor (2/0) the NEC is confident that the 4/0 can handle that load because it will not be over 180 amps often, if ever and it won't be for any period of time.

Now as a feeder that doesn't carry the load of the entire dwelling then 4/0 aluminum can be protected at 200 amps but the load calc cannot be greater than 180 amps. That is not a stipulation in a service-- for instance, if the calculated load of a service is 190 amps I can still use the 4/0 al or 2/0copper.


----------



## Wiresmith (Feb 9, 2013)

Dennis Alwon said:


> In a sense it does.


can i ask you a question? and yes it is a trap for my argument.



we are doing a new small commercial building, 
we have a 400 amp service from the utility(xfmr, cutout, meter base and there wire good for 400 amp)
the calculated minimum ampacity for the load is 125 amps

i install a 400amp service disconnect with 175 amp ocpd
my service conductors are 4/0 aluminum 75 degree in raceway (table 310.15(b)(16) compliant)


am i nec compliant?


----------



## sbrn33 (Mar 15, 2007)

hd13 said:


> can i ask you a question? and yes it is a trap for my argument.
> 
> 
> 
> ...


I know your are asking Dennis but I would say yes, yes you are. Just make sure you have your labeling up to date.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> can i ask you a question? and yes it is a trap for my argument.
> 
> 
> 
> ...



In your scenario you don't have a 400A service from the utility, you have a 175A service.

The size of the utility's wiring or transformer doesn't change your service size.

If there were multiple disconnects, then your (not the utility's) service entrance conductor size would denote the size of the service.


----------



## sbrn33 (Mar 15, 2007)

I use 600 Volt discos on 240 or 208 all the time if that is what you are getting at.


----------



## Arrow3030 (Mar 12, 2014)

HackWork said:


> In your scenario you don't have a 400A service from the utility, you have a 175A service.
> 
> The size of the utility's wiring or transformer doesn't change your service size.
> 
> If there were multiple disconnects, then your (not the utility's) service entrance conductor size would denote the size of the service.


This is dead on correct and should be accepted as the truth. It's also very easy to understand.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> In your scenario you don't have a 400A service from the utility, you have a 175A service.


i believe you said something like this before, i think you say a service is based on the ocpd closest downstream of the service conductors. am i correct with this?

this is a tangent from my point


----------



## HackWork (Oct 2, 2009)

hd13 said:


> i believe you said something like this before, i think you say a service is based on the ocpd closest downstream of the service conductors. am i correct with this?


I have said it at least a dozen times and I have been very clear each time. But you still bastardized what I said just now :vs_laugh:

A clown is the best way to describe you. You are one of the 3 trolls who argued against the GEC hole even though you couldn't come up with a stitch of evidence to support your side.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> In your scenario you don't have a 400A service from the utility, you have a 175A service.



2017 nec handbook 
310.15(B)(7)
explanatory material only in handbook
"the main service or feeder to a dwelling unit is permitted to be sized at 83% of the disco rating. the calculation is not based on the rating of the overcurrent device protecting the main feeder."


----------



## Wiresmith (Feb 9, 2013)

310.15
*(B) Tables.* Ampacities for conductors rated 0 to 2000 volts shall be as specified in allowable ampacity table 310.15(B)(16) through table 310.15(B)(19), and ampacity table 310.15(B)(20) and table 310.15(B)(21) as modified by 310.15(B)(1) through(B)(7).
The temperature correction and adjustment factors shall be permitted to be applied to the ampacity for the temp rating of the conductor, if corrected and adjusted ampacity does not exceed the ampacity for the temperature rating of the termination in accordance with the provisions of 110.14(C)


do you somehow think 310.15(B)(7) says you can overrate your terminals as well as the 4/0 aluminum?


----------



## Wiresmith (Feb 9, 2013)

hd13 said:


> i think you say a service is based on the ocpd closest downstream of the service conductors.






HackWork said:


> I have said it at least a dozen times and I have been very clear each time.




article 100

*service.*the conductors and equipment for delivering electric energy from the utility to the wiring system of the premises

*premises wiring(system).* interior and exterior wiring. including power, lighting, control, and signal circuit wiring together with all their associated hardware, fittings and wiring devices, both permanently and temporarily installed. this includes (a) wiring from the service point or power source to the outlets or (b) wiring from and including the power source to the outlets where there is no service point.

*service point.* the point connection between the facilities of the serving utility and the premises wiring

your ocpd is premises wiring not utility wiring


----------



## sbrn33 (Mar 15, 2007)

You do know the handbook is just opinion right?


----------



## HackWork (Oct 2, 2009)

hd13 said:


> 2017 nec handbook


 How many more times do I need to tell you that the NEC Handbook is not applicable?


----------



## Wiresmith (Feb 9, 2013)

sbrn33 said:


> You do know the handbook is just opinion right?


its nfpa70(national electrical code) handbook by nfpa

text from front of book

*notice concerning code interpretations*
"the handbook contains the complete text of nfpa 70 and any applicable formal interpretations issued by the nfpa at the time of publication."


how the f*** is the code book not applicable?


were going by uglys book or something?


the explanatory material is not code, if that is what you are saying. its explaining and talking about the code.

the code book is not a design manual it is a list of minimum requirements, the handbook goes further than just listing the requirements


this isn't from some mcgraw hill book or mike holt handbook


----------



## HackWork (Oct 2, 2009)

sbrn33 said:


> You do know the handbook is just opinion right?


He is arguing the same exact thing over and over. Everything that he is posting here he had already post a dozen times in the 2 other threads on this subject.

Everyone agreed that he was wrong. At least with the GEC hole he had 2 other trolls on his side, but with this he is alone.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> its nfpa70 handbook by nfpa
> 
> text from front of book
> 
> ...


"interpretations issued by the nfpa" are NOT code and AFAIK are not adopted into ANY municipality in this country.



> how the f*** is the code book not applicable?


 The code book is applicable, the Handbook is not.


----------



## macmikeman (Jan 23, 2007)

HackWork said:


> "interpretations issued by the nfpa" are NOT code and AFAIK are not adopted into ANY municipality in this country.
> 
> The code book is applicable, the Handbook is not.


I haven't bought a handbook in a number of decades , but the last one I did, they state right in the front that it is not the NEC and does not hold legal weight.


----------



## Wiresmith (Feb 9, 2013)

i'm not saying the explanatory material is code, i'm saying it is explaining and talking about the code

most of what i am posting is code, when i post explanatory material i say that


----------



## HackWork (Oct 2, 2009)

hd13 said:


> the explanatory material is not code, if that is what you are saying. its explaining and talking about the code.
> 
> the code book is not a design manual it is a list of minimum requirements, the handbook goes further than just listing the requirements
> 
> ...


You edit every post you make to write more and more in them after people have read them. That's very sneaky, only what a little weasel does.

Whatever is written in the Handbook is meaningless. It doesn't matter who wrote or published it. It has no meaning. It has no merit. How else could we get that thru your head? Why do you refuse to be educated?


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> You edit every post you make to write more and more in them after people have read them. That's very sneaky, only what a little weasel does.
> 
> Whatever is written in the Handbook is meaningless. It doesn't matter who wrote or published it. It has no meaning. It has no merit. How else could we get that thru your head? Why do you refuse to be educated?




LMAO why do you refuse to be educated, the handbook is eduaction on the codebook
from the people in charge of the codebook

unless my memory is failing me, you often cite mike holt


i do edit most of my posts, sorry, not trying to be sneaky, just think i make to many posts on the same thing already(trying to condense stuff)

i edited this one, lol


----------



## HackWork (Oct 2, 2009)

hd13 said:


> LMAO why do you refuse to be educated, the handbook is eduaction on the codebook


 No, it is not. It is one of tens of thousands of interpretations.

The municipalities purposely don't adopt the Handbook.


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> 2017 nec handbook
> 310.15(B)(7)
> explanatory material only in handbook
> "the main service or feeder to a dwelling unit is permitted to be sized at 83% of the disco rating. the calculation is not based on the rating of the overcurrent device protecting the main feeder."


I don't have the 2017 handbook so I can't verify what it actually says but this sounds like a paraphrase. 

Not that it really matters because the handbook isn't code.


----------



## sbrn33 (Mar 15, 2007)

hd13 said:


> its nfpa70 handbook by nfpa
> 
> text from front of book
> 
> ...


My state adopted the code book. the handbook is only opinion. I am guessing you are new to the trade. You will learn, give it time. If you really want to be an inspector as it seems you may want to got the fire Marshall route.


----------



## HackWork (Oct 2, 2009)

Arrow3030 said:


> I don't have the 2017 handbook so I can't verify what it actually says but this sounds like a paraphrase.
> 
> Not that it really matters because the handbook isn't code.


Yup, I doubt the Handbook says "disco".

But I didn't question it because, as you said, the Handbook isn't code and it doesn't matter what it says.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> Yup, I doubt the Handbook says "disco".
> 
> But I didn't question it because, as you said, the Handbook isn't code and it doesn't matter what it says.



word for word

"the main service or feeder to a dwelling unit is permitted to be sized at 83 percent of the disconnect rating. the calculation is not based on the rating of the overcurrent device protecting the main feeder. the minimum disconnect rating for a dwelling unit is 100 amperes according to 225.39 and 230.79. this calculation applies only to conductors carrying 100 percent of the dwelling unit's diversified load."


----------



## HackWork (Oct 2, 2009)

hd13 said:


> word for word
> 
> "the main service or feeder to a dwelling unit is permitted to be sized at 83 percent of the disconnect rating. the calculation is not based on the rating of the overcurrent device protecting *the main feeder*. the minimum disconnect rating for a dwelling unit is 100 amperes according to 225.39 and 230.79. this calculation applies only to conductors carrying 100 percent of the dwelling unit's diversified load."


The "main feeder" is not the service or service disconnect. You can go look those terms up in the definitions if you'd like.

You see, all this garbage you have been posting is all based on your mistake.

But this is all meaningless because what you just posted is from the Handbook and is no different than one of chicken steve's posts.


----------



## Wiresmith (Feb 9, 2013)

sbrn33 said:


> If you really want to be an inspector as it seems you may want to got the fire Marshall route.


i have no interest in being an inspector

i would like to try to help other electricians though


----------



## HackWork (Oct 2, 2009)

Here is a discussion at Mike Holt's in which someone explains that exact Handbook interpretation is poorly worded. 

http://forums.mikeholt.com/showthread.php?t=182815&p=1816003#post1816003

The Handbook is meaningless.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> Here is a discussion at Mike Holt's in which someone explains that exact Handbook interpretation is poorly worded.
> 
> http://forums.mikeholt.com/showthread.php?t=182815&p=1816003#post1816003
> 
> The Handbook is meaningless.


how is mike holt above nfpa on nfpas codebook?


----------



## HackWork (Oct 2, 2009)

hd13 said:


> how is mike holt above nfpa on nfpas codebook?


A) That is not Mike Holt.

B) Mike Holt is not "above" the NFPA, no one said that he is.

C) The Handbook is meaningless. 

So again, what don't you understand?


----------



## Wiresmith (Feb 9, 2013)

hackwork how do you argue against the terminal ratings?




hd13 said:


> 310.15
> *(B) Tables.* Ampacities for conductors rated 0 to 2000 volts shall be as specified in allowable ampacity table 310.15(B)(16) through table 310.15(B)(19), and ampacity table 310.15(B)(20) and table 310.15(B)(21) as modified by 310.15(B)(1) through(B)(7).
> The temperature correction and adjustment factors shall be permitted to be applied to the ampacity for the temp rating of the conductor, if corrected and adjusted ampacity does not exceed the ampacity for the temperature rating of the termination in accordance with the provisions of 110.14(C)
> 
> ...


----------



## Wiresmith (Feb 9, 2013)

my interpretation of this code requirement is not based on explanatory material, it is based on the NEC


i provided the explanatory material to further explain


----------



## macmikeman (Jan 23, 2007)

HackWork said:


> Here is a discussion at Mike Holt's in which someone explains that exact Handbook interpretation is poorly worded.
> 
> http://forums.mikeholt.com/showthread.php?t=182815&p=1816003#post1816003
> 
> The Handbook is meaningless.


I wouldn't go that far. It's good for apprentices to study with. Pictures are good for kids their age, words are not so easy for them to remember. Videos are even better. That's why I try to steer apprentices to the Mike Holt series when I can.


----------



## Arrow3030 (Mar 12, 2014)

It's a pretty awful handbook entry. It is making something fairly simple in the actual code more confusing.

If you are within the conditions of use of 310.15(b)(7) figure out your service/feeder rating and size your conductor to at least 83% of it.

I miss when it was a table.


----------



## HackWork (Oct 2, 2009)

Could this get any clearer? It's from the Handbook:

The commentary and supplementary materials in this handbook are not a part of the NFPA Document and do not constitute Formal Interpretations of the NFPA (which can be obtained only through requests processed by the responsible technical committees in accordance with the published procedures of the NFPA). The commentary and supplementary materials, therefore, solely reflect the personal opinions of the editor or other contributors and do not necessarily represent the official position of the NFPA or its technical committees.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> hackwork how do you argue against the terminal ratings?


I haven't argued against terminal ratings. I haven't even read that part of your post.

You are fishing for something and I won't feed into your trolling. Everything you said is wrong and everyone reading this knows that. So the question is... how much deeper are you going to dig your hole?


----------



## MTW (Aug 28, 2013)

I haven't owned a handbook in ages. It's about as useful as IAEI membership.


----------



## Wiresmith (Feb 9, 2013)

310.15(B)(7) does not say the conductor shall be permitted to be 83% of the amapcity of the conductor

it says the conductors shall be permitted to have ampacity not less than 83% of the service

theres a difference


----------



## HackWork (Oct 2, 2009)

hd13 said:


> 310.15(B)(7) doe snot say the condcutor shall be permitted to be 83% of the amapcity of the wire




No one here said that it did, you just made that up.


----------



## Wiresmith (Feb 9, 2013)

article 100

*service.*the conductors and equipment for delivering electric energy from the utility to the wiring system of the premises

*premises wiring(system).* interior and exterior wiring. including power, lighting, control, and signal circuit wiring together with all their associated hardware, fittings and wiring devices, both permanently and temporarily installed. this includes (a) wiring from the service point or power source to the outlets or (b) wiring from and including the power source to the outlets where there is no service point.

*service point.* the point connection between the facilities of the serving utility and the premises wiring

your ocpd is premises wiring not utility wiring


----------



## macmikeman (Jan 23, 2007)

Arrow3030 said:


> It's a pretty awful handbook entry. It is making something fairly simple in the actual code more confusing.
> 
> If you are within the conditions of use of 310.15(b)(7) figure out your service/feeder rating and size your conductor to at least 83% of it.
> 
> I miss when it was a table.


I miss when it was a proper table, you know like when it was ok to use #2 alum ser for 100 amp subfeeds to panels. They changed it to make it like nm cable just cause some dumbasses complained that the code wasn't consistent. 
Jackasses. #2 ser can safely carry a 100 amp service, and 2/0 alum ser can safely carry a 200 amp service and there are thousands and thousands of existing homes in the USA with one of those service cables which have not suddenly burst into flames. Neither are allowed since 2005 however. This whole thread is pissing me off since nobody even has brought these facts up yet.


----------



## HackWork (Oct 2, 2009)

Keep posting the same thing over and over. It might get you somewhere :vs_laugh:


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> No one here said that it did, you just made that up.


thats what your doing by using a 4/0 alum 75 degree with 200 amp ocpd


----------



## HackWork (Oct 2, 2009)

hd13 said:


> thats what your doing by using a 4/0 alum 75 degree with 200 amp ocpd


No, I am not doing that.

I am using the service size, which is the size of the service disconnect OCPD, to size the service entrance conductors. That's what everyone does. But you :vs_laugh:


----------



## Wiresmith (Feb 9, 2013)

*service.*the conductors and equipment for delivering electric energy from the utility to the wiring system of the premises


----------



## Wiresmith (Feb 9, 2013)

*premises wiring(system).* interior and exterior wiring. including power, lighting, control, and signal circuit wiring together with all their associated hardware, fittings and wiring devices, both permanently and temporarily installed. this includes (a) wiring from the service point or power source to the outlets or (b) wiring from and including the power source to the outlets where there is no service point.

*service point*. the point connection between the facilities of the serving utility and the premises wiring

your ocpd is premises wiring not the service


----------



## Wiresmith (Feb 9, 2013)

i'm looking it up now, but i think the table was removed because of the misinterpretation you all have


----------



## macmikeman (Jan 23, 2007)

hd13 said:


> i'm looking it up now, but i think the table was removed because of the misinterpretation you all have


You should be on a code panel. Because you will not listen to what the real electricians are telling you. That's what code panel guys do.


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> i'm looking it up now, but i think the table was removed because of the misinterpretation you all have


I'm pretty sure it was removed because the condition of use still includes adjustments and corrections.


----------



## TheLivingBubba (Jul 23, 2015)

hd13 said:


> i'm looking it up now, but i think the table was removed because of the misinterpretation you all have


It was removed in the 2014 code cycle.


----------



## MTW (Aug 28, 2013)

This thread is another example of the divide between code rules and what we know works in real life.


----------



## Wiresmith (Feb 9, 2013)

yep thats why they got rid of it ill post it in a minute


----------



## HackWork (Oct 2, 2009)

Hey look, he posted the definitions that he doesn't understand for the 7th time in this thread, and 2nd time on this page :vs_laugh::vs_laugh::vs_laugh:


----------



## Wiresmith (Feb 9, 2013)

2013 annual revision cycle nec committee report on comments

comment 6-41
310.15(B)(7)
panel statement

"Use of the table does improve usability of the NEC if
conditions of use don’t require correction factors. The problem of using the
table is that the user has no way to apply the required adjustment factors to the
types of insulation dependent upon conditions of installation.
The panel affirms that the new language accepted in Comment 6-52 is a
compromise to address the misuse of prior published table. "


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> 2013 annual revision cycle nec committee report on comments
> 
> comment 6-41
> 310.15(B)(7)
> ...


So I was right in my guess. BFD.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> 2013 annual revision cycle nec committee report on comments
> 
> comment 6-41
> 310.15(B)(7)
> ...


That wasn't a misinterpretation that I ever had.


----------



## Wiresmith (Feb 9, 2013)

they removed it because of you stubborn jack***'


----------



## HackWork (Oct 2, 2009)

hd13 said:


> they removed it because of you stubborn jack***'


No, not at all. Not in any way.

You are so way off base that you don't even know where you began.


----------



## Dennis Alwon (May 9, 2009)

The table was removed because it did not take into consideration any de-rating factors that may be pertinent. For instance, back when se cable was rated 60 amps the code stated simply that for a 200 amp service we could use 4/0 alum. Now this conductor is rated differently if it is in conduit, cable, run thru insulation in an attic etc,. The table ignored those factor.

The new section, which is basically the same as the table does take into the de-rating factor by saying if you have a 200 amp service then the conductor can be sized 83% of 200 amps after de-rating. So as long as the conductors have a rating of 166 amps or better after all factors are taken into consideration, then you can use that conductor for 200 amps for a dwelling.

Hd, in response to your question awhile ago-- yes, you can do what you stated but the service, as Hackwork stated, is 175 amps because that is the size of the overcurrent protective device. You cannot have more than 175 amps on that service unless you change the overcurrent protective device .\

So, you keep jumping back from resi to commercial-- 83% applies to resi work nopt commercial because the chance of the conductor seeing a larger load is much more likely in a commercial setting


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> they removed it because of you stubborn jack***'


How do you think the CMP you posted defends your case? It doesn't...


----------



## Wiresmith (Feb 9, 2013)

this was right beside that, heres for your almighty holt hackwork


6-43 Log #1014 NEC-P06 Final Action: Reject
(310.15(B)(7))
__________________
Submitter: Mike Holt, Mike Holt Enterprises
Comment on Proposal No: 6-19
Recommendation: ....really long read it yourself...
Panel Meeting Action: Reject


----------



## Wiresmith (Feb 9, 2013)

Arrow3030 said:


> How do you think the CMP you posted defends your case? It doesn't...


they got rid of the table because you guys were using it incorrectly


----------



## Dennis Alwon (May 9, 2009)

Let's cut the name calling please.... Move on if you don't want to respond without insults. I know it is frustrating to say it over and over so just stop posting. I think the info is here.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> this was right beside that, heres for your almighty holt hackwork
> 
> 
> 6-43 Log #1014 NEC-P06 Final Action: Reject
> ...


What you are saying makes no sense. Nothing you have makes any sense. I post 1 link to a discussion on a forum that happens to be on Mike Holt's website. So what? I'm not even a member while Dennis is a moderator there, go complain to him.

How long are you going to play rebel?


----------



## HackWork (Oct 2, 2009)

hd13 said:


> they got rid of the table because you guys were using it incorrectly


When you say "you guys", who do you mean and how did they use it incorrectly?


----------



## Arrow3030 (Mar 12, 2014)

hd13 said:


> Arrow3030 said:
> 
> 
> > How do you think the CMP you posted defends your case? It doesn't...
> ...


No one had mentioned anything about adjustments, corrections or other conditions of use until this point.

You don't get to say you are right. Sorry. You're still wrong. 

If anything, you using the CMP (or whatever that came from) to prove you're right shows more of a lack of your understanding of more of 310.15.

I'm kinda fired up now. I'd try to write that more better if you weren't driving me nuts lol.


----------



## Wiresmith (Feb 9, 2013)

_______________________________________________________________
6-53 Log #1558 NEC-P06 Final Action: Accept in Principle
(310.15(B)(7))
________________________________________________________________
Submitter: Frederic P. Hartwell, Hartwell Electrical Services, Inc.
Comment on Proposal No: 6-49a
Recommendation: Accept the proposal in principle. Revise text to read as
follows:
For service or feeder conductors of 120/240-volt single phase systems rated
100 through 400 amperes and used to supply all loads that are part of or
associated with an individual dwelling unit of a single-family, two-family, or
multifamily dwelling, an adjustment factor of 0.83 shall be permitted to be
applied to the service or feeder ampere rating for the purpose of determining
the size of the ungrounded conductors.
Substantiation: This is a largely editorial comment that flows better and
resolves the problem that the panel text refers to two-family and multi-family
service ratings, and often the relevant rating will not be a service rating but a
feeder rating instead. Although not intended, the panel text does support an
interpretation that this provision applies to a multifamily service rating, since
the individual dwelling unit rating in such an occupancy would be supplied by
a feeder and would not have a “service rating”. The comment also retains the
important concept that the provision only applies to conductors that see the
entire load and therefore benefit from the diversity present is such a load.
Panel Meeting Action: Accept in Principle
Panel Statement: See panel action and statement on Comment 6-52.
Number Eligible to Vote: 10
Ballot Results: Affirmative: 9 Negative: 1
Explanation of Negative:
STACEY, J.: The panel action should have been “Reject.” See my comments
on 6-41, 6-45 and 6-52.
Comment on Affirmative:
KENT, G.: See statement in 6-52.


----------



## HackWork (Oct 2, 2009)

As I explained to you, posting the same things over and over isn't going to get you anywhere. Nothing you posted supports your assertions.


----------



## Wiresmith (Feb 9, 2013)

the 83% is for figuring the required service ampacity, not to overrate the ungrounded conductors, the conductors must have ocpd per their ampacity


let alone the connectors


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> As I explained to you, posting the same things over and over isn't going to get you anywhere. Nothing you posted supports your assertions.


thats a different one columbo


----------



## Wiresmith (Feb 9, 2013)

the 83% is for 


say you have a 200 amp service from the utility

say your building's calculated load does not require 200a

you can forgo using wires for the 200a service(because your building doesn't need 200a)

but that is irrelevant to the ocpd on your wires

if your building doesn't need 200a and you use smaller wire because of that, what the F*** is the point of having the larger ocpd. we already said you dont need the 200 amps


----------



## HackWork (Oct 2, 2009)

hd13 said:


> the 83% is for figuring the required service ampacity, not to overrate the ungrounded conductors, the conductors must have ocpd per their ampacity
> 
> 
> let alone the connectors


No, you size the service entrance conductors according to the breaker size on the service disconnect.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> thats a different one columbo


It's the same garbage which doesn't support any of your assertions. It's just a wall of text. Nothing in it supports the incorrect code that you posted.


----------



## Arrow3030 (Mar 12, 2014)

HackWork said:


> It's the same garbage which doesn't support any of your assertions. It's just a wall of text. Nothing in it supports the incorrect code that you posted.


I was about to say the same thing. I read 6-43 from holt which HD refenced but didn't copy the text. Nothing in there to support him either FYI. It was an interesting read though.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> the 83% is for
> 
> 
> say you have a 200 amp service from the utility


 This is where you are wrong again, as I explained to you at least a dozen times over the course of 3 threads. The utility doesn't "give you" current. The utility has nothing to do with your service size. 

The utility might feed your 200A service with a 25 kVA tranny and #2 conductor, while they might feed another house with a 75 kVA tranny and #6 conductor. That is left to their discretion and is ultimately up to their engineers. 

It does NOT change the service size of the house in question. The fact that you keep saying "the utility gives us 200A" makes me think you have no electrical experience at all. Kinda like the way homeowners don't understand how voltage is a constant while current is drawn.



> say your building's calculated load does not require 200a
> 
> you can forgo using wires for the 200a service(because your building doesn't need 200a)
> 
> ...


 The current rating of the OCPD is the service size and what you size the service entrance conductors to.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> No, you size the service entrance conductors according to the breaker size on the service disconnect.


230.90 (A)
each ungrounded service conductor shall have overload protection.such protection shall be provided by an overcurrent device in series with each ungrounded service conductor that has a rating or setting not higher than the allowable ampacity of the conductor.


----------



## Wiresmith (Feb 9, 2013)

310.15(B)(7) is ampacity of the service rating


----------



## Wiresmith (Feb 9, 2013)

not 83% of the conductor rating


----------



## HackWork (Oct 2, 2009)

hd13 said:


> 230.90 (A)
> each ungrounded service conductor shall have overload protection.such protection shall be provided by an overcurrent device in series with each ungrounded service conductor that has a rating or setting not higher than the allowable ampacity of the conductor.


And then we have 310.15(B)(7). Have you heard of it?? :vs_laugh:


----------



## Wiresmith (Feb 9, 2013)

conductor rating is the wiring methods respected table such as 310.15(B)(16)


----------



## HackWork (Oct 2, 2009)

hd13 said:


> conductor rating is the wiring methods respected table such as 310.15(B)(16)


Again, no one has a clue what you are talking about.


Don't you realize that when you are alone against everyone else in the world, it is you who needs to realize that he is mistaken?


----------



## Wiresmith (Feb 9, 2013)

the only mistake i made was trying to help you guys.

no good deed goes unpunished.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> the only mistake i made was trying to help you guys.
> 
> no good deed goes unpunished.


Keep telling yourself that.


----------



## HackWork (Oct 2, 2009)

I notice that you never replied to my post #247 just like you didn't reply when I explained the same thing in the other threads. 

We know why.... because it blows your whole theory out of the water and shows how little about this you truly know.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> Again, no one has a clue what you are talking about.


the ampacity rating of 4/0 aluminum for 75degree insulation and terminals, not more than 3 conductors in raceway, based on ambient temp of 30c is 180amps
see table 310.15(B)(16)

allowable ampacity

amp-acity
amp capacity(maximum)(except under engineering calcs)


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> I notice that you never replied to my post #247 just like you didn't reply when I explained the same thing in the other threads.
> 
> We know why.... because it blows your whole theory out of the water and shows how little about this you truly know.


247 excerpt
post 


HackWork said:


> The utility has nothing to do with your service size.



so you put in 400amp main breaker and 900kcmil service conductors what used to be a 100 amp service, utility doesnt change anything. 

you think you have a 400amp service?


----------



## HackWork (Oct 2, 2009)

hd13 said:


> the ampacity rating of 4/0 aluminum for 75degree insulation and terminals, not more than 3 conductors in raceway, based on ambient temp of 30c is 180amps
> see table 310.15(B)(16)
> 
> allowable ampacity
> ...


What is your point? Who are you arguing with that said something different?


----------



## Wiresmith (Feb 9, 2013)

the only thing blowing here is your argument and cutt-outs of your last service upgrade


----------



## HackWork (Oct 2, 2009)

hd13 said:


> 247 excerpt
> post
> 
> 
> ...


Yes. I *know* that I have a 400A service for an absolute fact.


I do it all the time. I upgrade 60A services to 200A, the utility doesn't change anything.


----------



## Wiresmith (Feb 9, 2013)

*service.*the conductors and equipment for delivering electric energy from the utility to the wiring system of the premises


----------



## Wiresmith (Feb 9, 2013)

*premises wiring(system).* interior and exterior wiring. including power, lighting, control, and signal circuit wiring together with all their associated hardware, fittings and wiring devices, both permanently and temporarily installed. this includes (a) wiring from the service point or power source to the outlets or (b) wiring from and including the power source to the outlets where there is no service point.

*service point*. the point connection between the facilities of the serving utility and the premises wiring

your ocpd is premises wiring not the service


----------



## HackWork (Oct 2, 2009)

hd13 said:


> the only thing blowing here is your argument and cutt-outs of your last service upgrade


All of my service upgrades are approved by the utility wiring inspectors. I never had an issue of a cut-out opening.

Now I remember in your other thread in which you said that cut-outs will open if you pull more than 200A. That alone clearly shows that you don't have a clue about any of this.

But by all means, keep making yourself look foolish.


----------



## HackWork (Oct 2, 2009)

hd13 said:


> *service.*the conductors and equipment for delivering electric energy from the utility to the wiring system of the premises





hd13 said:


> *premises wiring(system).* interior and exterior wiring. including power, lighting, control, and signal circuit wiring together with all their associated hardware, fittings and wiring devices, both permanently and temporarily installed. this includes (a) wiring from the service point or power source to the outlets or (b) wiring from and including the power source to the outlets where there is no service point.
> 
> *service point*. the point connection between the facilities of the serving utility and the premises wiring
> 
> your ocpd is premises wiring not the service


Good job posting those definitions yet again! :vs_laugh::vs_laugh::vs_laugh:


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> All of my service upgrades are approved by the utility wiring inspectors. I never had an issue of a cut-out opening.
> 
> Now I remember in your other thread in which you said that cut-outs will open if you pull more than 200A. That alone clearly shows that you don't have a clue about any of this.
> 
> But by all means, keep making yourself look foolish.


with a 200amp fuse, they sure will buddy. do you know which way the wire wraps around the screw on the receptacle?


----------



## HackWork (Oct 2, 2009)

hd13 said:


> with a 200amp fuse, they sure will buddy. do you know which way the wire wraps around the screw on the receptacle


:vs_laugh::vs_laugh::vs_laugh::vs_laugh:


----------



## Wiresmith (Feb 9, 2013)

glad we could share a laugh


----------



## HackWork (Oct 2, 2009)

hd13 said:


> glad we could share a laugh


We aren't sharing a laugh, I am laughing at you.

Please, tell me more about these cut-outs that open when a homeowners draws more than 200A :vs_laugh::vs_laugh::vs_laugh:


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> We aren't sharing a laugh, I am laughing at you.
> 
> Please, tell me more about these cut-outs that open when a homeowners draws more than 200A :vs_laugh::vs_laugh::vs_laugh:



good question

when they have a 200 amp fuse, it goes boo and falls open, if more than 200amps runs through it for a long enough time


----------



## Wiresmith (Feb 9, 2013)

now, that your listening lets try going over ocpd required for conductors again


----------



## Wiresmith (Feb 9, 2013)

if you look back in the 68' code book, i think this is where the idea for b7 derived. it has a table for diversification, continuous and non-continuous loads and the wire size for those loads, the kicker is the amps is for the load not the ocpd, the ocpd still needs sized per the conductor ampacity


----------



## HackWork (Oct 2, 2009)

Do you own a shotgun? Have you ever worked on it? If I send you a toe-trigger attachment, do you think you can install?


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> Do you own a shotgun? Have you ever worked on it? If I send you a toe-trigger attachment, do you think you can install?


does it come with a handbook?


----------



## Dennis Alwon (May 9, 2009)

After all this I am not sure what your point is HD. Are you saying that if I calculate the load of a house at 200 amps that I cannot use the 83% rule? If so, then you are just plain incorrect. There is nowhere in tyhe rules that say you can use 83% only if the load is lower than the ampacity of the conductor.

The 83% is the one time that you can overide T. 310.15(B)(16)


----------



## Bird dog (Oct 27, 2015)

Hax, you need to start charging for teaching. Patreon may work. :wink:


----------



## chicken steve (Mar 22, 2011)

macmikeman said:


> I haven't bought a handbook in a number of decades , but the last one I did, they state right in the front that it is not the NEC and does not hold legal weight.


From my '17 Non-HB>>>>


> > NOTICE AND DISCLAIMER OF LIABILITY CONCERNING THE USE OF NFPA STANDARDS
> 
> 
> NFPA® codes, standards, recommended practices, and guides (“NFPA Standards”), of which the document contained herein
> ...


:vs_cool:
~CS~


----------



## chicken steve (Mar 22, 2011)

hd13 said:


> now, that your listening lets try going over ocpd required for conductors again


the only thing this thread is missing is _'next highest'_ in art 240


:vs_cool:
~CS~


----------



## Bird dog (Oct 27, 2015)

What do you call a chicken that crosses the road, rolls around in the dirt & crosses back over the road?...A dirty double crosser!!! :vs_laugh:


----------



## Wiresmith (Feb 9, 2013)

Dennis Alwon said:


> There is nowhere in tyhe rules that say you can use 83% only if the load is lower than the ampacity of the conductor.


i believe you are correct
it does not say that

because the 83% is not for what you are thinking


the part's of the code you are forgetting is

-conductors must have the ampacity for there intended load

-conductors must have overload protection for their ampacity


----------



## Wiresmith (Feb 9, 2013)

83% is for what i have said more than enough times in this thread

it is not for rating a specific wiring method


----------



## emtnut (Mar 1, 2015)

hd13 said:


> with a 200amp fuse, they sure will buddy. do you know which way the wire wraps around the screw on the receptacle?


Can't speak for US power distribution, but the cut-out is on the H side of the transformer. 
200A fuse would be a little high given it's at 7620V :vs_laugh:


----------



## Bird dog (Oct 27, 2015)

emtnut said:


> Can't speak for US power distribution, but the cut-out is on the H side of the transformer.
> 200A fuse would be a little high given it's at 7620V :vs_laugh:


Also, the POCO will overload xfmrs because it's cheaper than replacing them.


----------



## Wiresmith (Feb 9, 2013)

emtnut said:


> Can't speak for US power distribution, but the cut-out is on the H side of the transformer.
> 200A fuse would be a little high given it's at 7620V :vs_laugh:


doesnt matter which side the cutout is on, if 200 passes through the cut-out with a 200 long enough it is supposed to open


----------



## HackWork (Oct 2, 2009)

emtnut said:


> Can't speak for US power distribution, but the cut-out is on the H side of the transformer.
> 200A fuse would be a little high given it's at 7620V :vs_laugh:


It's the same here as up there I am sure.

He thinks that cut-outs are fuses that will blow if you pull more power than your service size. 

The truth, as you know, is that you can have a dead short and it will continue to short until enough metal has blown away to clear itself. The cut-outs aren't going to open.


----------



## Wiresmith (Feb 9, 2013)

HackWork said:


> It's the same here as up there I am sure.
> 
> He thinks that cut-outs are fuses that will blow if you pull more power than your service size.
> 
> The truth, as you know, is that you can have a dead short and it will continue to short until enough metal has blown away to clear itself. The cut-outs aren't going to open.


most cut-outs have fuses


----------



## HackWork (Oct 2, 2009)

hd13 said:


> most cut-outs have fuses


For all intents and purposes, cut-outs are fuses. But they aren't there to limit consumer power.


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## Wiresmith (Feb 9, 2013)

HackWork said:


> For all intents and purposes, cut-outs are fuses. But they aren't there to limit consumer power.


you can put in a knife instead of a fuse genius

the fuses open when current is over there limit for the required time


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## Wiresmith (Feb 9, 2013)

i have a strange feeling like were not getting anywhere


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## MTW (Aug 28, 2013)

hd13 said:


> most cut-outs have fuses


:001_huh:

If you are talking about a cutout for a transformer, it mostly certain is fused in all cases.


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## Bird dog (Oct 27, 2015)

hd13 said:


> you can put in a knife instead of a fuse genius


And I betcha the unicorns would do it!!!:surprise:


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## HackWork (Oct 2, 2009)

hd13 said:


> i have a strange feeling like were not getting anywhere


Actually, you are getting further and further into your journey of making yourself look like a complete idiot.

Let's see what you say next.


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## chicken steve (Mar 22, 2011)

hd13 said:


> i have a strange feeling like were not getting anywhere


In honesty, the 83% thing has been is dispute since it's inception

I miss the table.....


:sad:
~CS~


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## MTW (Aug 28, 2013)

Abolish the NEC. It's time for common sense to return.


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## emtnut (Mar 1, 2015)

hd13 said:


> doesnt matter which side the cutout is on, if 200 passes through the cut-out with a 200 long enough it is supposed to open


200A on the primary, or secondary ... doesn't matter huh :vs_laugh:

Pocos don't give a chit about their transformers. They have a yard full of them to replace if necessary. You can run 2 - 3 - even 400% out of them. They just get hot :biggrin:


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## MTW (Aug 28, 2013)

In my area it's common for 10 or more houses to share one 50 kva transformer. These are small houses and the majority of them are all gas, no central a/c.


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## Wiresmith (Feb 9, 2013)

post 74 in this thread


HackWork said:


> All this doesn't matter because the power company turns on the hose to 200A. Anything more and their cut-outs will blow!


post 285


HackWork said:


> It's the same here as up there I am sure.
> 
> He thinks that cut-outs are fuses that will blow if you pull more power than your service size.
> 
> The truth, as you know, is that you can have a dead short and it will continue to short until enough metal has blown away to clear itself. The cut-outs aren't going to open.


LMAO, which is it?

you are such a bu** sh***** you are fooling yourself(and others)


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## Wiresmith (Feb 9, 2013)

to try to put this to rest, i will say it appears to be more often interpreted that b7 allows overating, but i believe that interpretation is incorrect if you consider the rest of the code book and the code books of the past


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## Arrow3030 (Mar 12, 2014)

hd13 said:


> i have a strange feeling like were not getting anywhere


Your smartest post yet. Too bad you're pointing it the wrong way!


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## RePhase277 (Feb 5, 2008)

hd13 said:


> they got rid of the table because you guys were using it incorrectly


The table was put back I to the 2017 code, but it's in the tables or annex. I forget which.


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## MTW (Aug 28, 2013)

Abolish the NEC!


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## Wiresmith (Feb 9, 2013)

RePhase277 said:


> The table was put back I to the 2017 code, but it's in the tables or annex. I forget which.


i agree there's nothing wrong with the table. in an earlier post i posted the code making panels discussion on why the table was removed. they said it was because "....to address the misuse of prior published table."


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## Arrow3030 (Mar 12, 2014)

hd13 said:


> i agree there's nothing wrong with the table. in an earlier post i posted the code making panels discussion on why the table was removed. they said it was because "....to address the misuse of prior published table."


Don't bring that noise back in here. You posted that CMP to try and prove your point and it failed. The misuse stated in the CMP dicussions has nothing to do with your defense.


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## Wiresmith (Feb 9, 2013)

Arrow3030 said:


> Don't bring that noise back in here. You posted that CMP to try and prove your point and it failed. The misuse stated in the CMP dicussions has nothing to do with your defense.


part of my "defense" is misuse/misunderstanding
if someone doesn't understand B7 they don't understand B7


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## HackWork (Oct 2, 2009)

hd13 said:


> post 74 in this thread
> 
> post 285
> 
> ...


Do you really not understand that in post #74 I was *mocking you* and your complete lack of knowledge?


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## Wiresmith (Feb 9, 2013)

HackWork said:


> Do you really not understand that in post #74 I was *mocking you* and your complete lack of knowledge?


you were not mocking, 

before you said that i said nothing about a current limit for the fuses. there was nothing to mock, i only mentioned cut out fuse size after you did with that post


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## HackWork (Oct 2, 2009)

hd13 said:


> you were not mocking,
> 
> before you said that i said nothing about a current limit for the fuses. there was nothing to mock, i only mentioned cut out fuse size after you did with that post


Yes, I was mocking you because you said that about the Cut-outs in the other thread.

Honestly, you are lying to yourself now and it's time to stop. Quit making a fool of yourself. I'm starting to feel bad.


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## emtnut (Mar 1, 2015)

hd13 said:


> you were not mocking,
> 
> before you said that i said nothing about a current limit for the fuses. there was nothing to mock, i only mentioned cut out fuse size after you did with that post


Sorry bud ... he was mocking you.

Hax has posted about it before, he's well aware of Tx cutouts :wink:


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## HackWork (Oct 2, 2009)

Since you are going to continue to lie about it, I looked it up. Here is where you said it last month:



hd13 said:


> i will add this for anyone that is sweating, the ocpd the poco has will probably blow when the sec fails, before a fire starts


That is INSANE to say. The cut-out won't open, it will allow arc blasting until it clears itself. 

That shows that you have no idea how any of this works. And that is why I mocked you about it yet again in this thread.


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## Wiresmith (Feb 9, 2013)

HackWork said:


> Yes, I was mocking you because you said that about the Cut-outs in the other thread.


are you talking about the thread "size feeder for resi 200a panel 4/0?"

i dont see me saying anything about cutouts or utility fuses anywhere in that thread


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## Wiresmith (Feb 9, 2013)

HackWork said:


> Since you are going to continue to lie about it, I looked it up. Here is where you said it last month:
> 
> 
> 
> ...


that is not saying the fuse will blow when you go over the service rating, that is talking about a short circuit.


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## HackWork (Oct 2, 2009)

hd13 said:


> are you talking about the thread "size feeder for resi 200a panel 4/0?"
> 
> i dont see me saying anything about cutouts or utility fuses anywhere in that thread


Oh how convenient that you forgot lol...

Look one post up.


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## HackWork (Oct 2, 2009)

hd13 said:


> that is not saying the fuse will blow when you go over the service rating, that is talking about a short circuit.


No, it wasn't. We were talking about 200A on 4/0. We never mentioned a short circuit. I just read the discussion you liar.


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## Wiresmith (Feb 9, 2013)

HackWork said:


> Since you are going to continue to lie about it, I looked it up. Here is where you said it last month:
> 
> 
> 
> ...


when the cutout fuse opens/blows, it is supposed and usually does open the cutout


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## HackWork (Oct 2, 2009)

hd13 said:


> when the cutout fuse blows, it is supposed and usually does open the cutout


Again you post something that is not only stupid, but has nothing to do with the discussion.


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## Wiresmith (Feb 9, 2013)

HackWork said:


> No, it wasn't. We were talking about 200A on 4/0. We never mentioned a short circuit. I just read the discussion you liar.


this is the post

"i will add this for anyone that is sweating, the ocpd the poco has will probably blow when the sec fails, before a fire starts"


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## Wiresmith (Feb 9, 2013)

i didnt say when it went over the service rating, by fail i meant something happening like the conductors insulation melt and causing a short


how does secondary failing mean 200 amp on 175 amp wire?
theres no way you interpreted it like that


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## HackWork (Oct 2, 2009)

hd13 said:


> this is the post
> 
> "i will add this for anyone that is sweating, the ocpd the poco has will probably blow when the sec fails, before a fire starts"


Jesus you are thick skulled.

You were talking about the 4/0 not being able to handle 200A and the insulation failing.

You talk in circles and don't even know what you are trying to say. You are looking for any way to win this when the fact is that every single thing you have posted has been wrong and plain old dumb.

I can only make you look _so_ stupid, so I will stop here.


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## Wiresmith (Feb 9, 2013)

this is ridiculous, sorry 
we just interpret the code differently, you may be right. ive just tried to post what makes me think differently


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## RePhase277 (Feb 5, 2008)

This thread has made me have a priapism.


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## Wiresmith (Feb 9, 2013)

RePhase277 said:


> This thread has made me have a priapism.


its probably been long enough, you can go back and read "GEC entering enclosure"
lol
its hard to look away from a train wreck


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## Arrow3030 (Mar 12, 2014)

hd13 said:


> Arrow3030 said:
> 
> 
> > Don't bring that noise back in here. You posted that CMP to try and prove your point and it failed. The misuse stated in the CMP dicussions has nothing to do with your defense.
> ...


You don't get to change your stance based on references you bring to the table.

Misunderstanding b7 is what you're doing. Not me, not hack and not Dennis.

I'm not sure how long you've been a member but I'll give you some advice. When Dennis and hack agree on someone's folly, listen.

The misuse discussed in the CMP has absolutely nothing to do with your original protests. The CMP has it right and implemented the correction poorly. That doesn't give you a leg though.


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## Wiresmith (Feb 9, 2013)

not changing my stance, i believe the reference supports that there was misuse/misinterpretation and the cmp removed the table to try to clear it up


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## Arrow3030 (Mar 12, 2014)

hd13 said:


> not changing my stance, i believe the reference supports that there was misuse/misinterpretation of the table


If that was your sole point all along I might have agreed. But it wasn't. You have changed your stance and that's fine with me.

Don't try to say you were right all along though. That's a bunch of NOISE!


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## Wiresmith (Feb 9, 2013)

Arrow3030 said:


> If that was your sole point all along I might have agreed. But it wasn't. You have changed your stance and that's fine with me.
> 
> Don't try to say you were right all along though. That's a bunch of NOISE!



that was only my point with that cmp comment, its not my point on this discussion of b7 i believe it only allows the service to be derated, not conductors overrated. not trying to say i was right all along, just trying to explain why i think b7 is how i interpret it. i don't care who is right, if im wrong i want to be proven the correct interpretation based on code not going by how my buddy's have always done things.


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## Arrow3030 (Mar 12, 2014)

Okay. That's good enough for me. As long as you admit, which you just did, that no one was talking about the misuse discussed in the CMP which lead to the code change and that it has nothing to do with you're misunderstanding of b7.


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