# Interesting Lighting Problem



## MDShunk (Jan 7, 2007)

The video below is from the Maintenance Geeks website. It's what happens when you have a dead leg on 347 lighting. I imagine the same thing would happen with 277.


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## JoeKP (Nov 16, 2009)

That actually looks pretty cool


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## drsparky (Nov 13, 2008)

I've never seen anything like that.


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## MDShunk (Jan 7, 2007)

I've seen a dead leg make all the lighting on that leg go dim, but never flash on like that. I guess it mostly depends on the load types on the good legs.


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## JohnR (Apr 12, 2010)

I have seen something similar at a school. The voltage was 277, the lights were over the lockers. I was disconnecting the circuits in the emergency panel and re-routing them when I got a call from maintenance. 
The lights over the hall lockers were doing that flash, some were on, some would do that flash at a slower rate. Kind of a cool effect.

What I found out, the neutrals on normal, emergency lighting ,fed from two far different panels, were all tied together in a few different j-boxes. 
Which told me why I had an arc from the neutral when I disconnected it even though the panel was off.


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## Shorty Circuit (Jun 26, 2010)

There are several ways this can happen. The most common way is for an open neutral on a multiwire branch circuit. It can happen to the loads on any wye secondary transformer including 120/208. It isn't the only way though. You can have one open phase on the primary delta side. An interwinding short circuit within the transformer, that is a short between different points on the same winding on the primary delta side will reduce the turns ratio to the secondary and increase the secondary voltage.

When the neutral opens, the voltage between each pair of windings is divided across the loads by the equivalent parallel impedences of each load. As the loads burn up, the voltage will continue to redistribute which is why they don't blow all at once. There are other reasons to avoid multiwire branch circuits even though the commentary in the code handbook makes it clear that the authors of the code like them. In my specs they are strictly prohibited except for a single load where that is the manufacturer's required source.


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## 480sparky (Sep 20, 2007)

drsparky said:


> I've never seen anything like that.



I have. At the cinema.


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## Big John (May 23, 2010)

Yeah, that's a new one to me, too. 

I'm assuming that on an incandescent circuit this wouldn't happen because all the lamps would light uniformly at the same time. In this case, I think it only happens because of differences in strike-time between lamps, and as a result, an erratic change in the over-voltage in the circuit MWBC?

Is that a true statement?

(And I love _Close Encounters_...  )

-John


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## millerdrr (Jun 26, 2009)

Shorty Circuit said:


> There are other reasons to avoid multiwire branch circuits even though the commentary in the code handbook makes it clear that the authors of the code like them. In my specs they are strictly prohibited except for a single load where that is the manufacturer's required source.


You prohibit MWBCs?










Let$ talk...:laughing:


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## Bob Badger (Apr 19, 2009)

Shorty Circuit said:


> In my specs they are strictly prohibited except for a single load where that is the manufacturer's required source.


Short sighted specs, see them all the time.


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## Shorty Circuit (Jun 26, 2010)

Big John said:


> Yeah, that's a new one to me, too.
> 
> I'm assuming that on an incandescent circuit this wouldn't happen because all the lamps would light uniformly at the same time. In this case, I think it only happens because of differences in strike-time between lamps, and as a result, an erratic change in the over-voltage in the circuit MWBC?
> 
> ...


Oh really? Why don't you try it? Wire up a 120-240 multiwire branch circuit in your house with say 3 to 6 lamps on one circuit and just one on the other. Then open up the neutral. You'd better wear safety glasses when you do. Better yet a face shield.

In the video clip, what is happening on what appears to be a three phase circuit with an open neutral is more complex and interesing. Notice that the lights do not blow out. the same lamps fire up again and again in around 3 to 5 second intervals. Watch carefully focusing on just one lamp for the entire clip and you will see. What appears to be happening is that when the voltage on one lamp gets high enough, it fires up. The flow of current reduces its impedence and the voltage across it drops below its operating range and then it goes out. The highest percentage of the volatge for that pair of phases is across a different fixture and the same thing happens, it's in a harmonic resonance failure mode which could go on for a very long time as the voltages between each pair of phases floats around and around. It's as if the lamps were in series and in fact they are. That's the effect of opening the neutrals, placing the lamps in series at 347volts in a traiangular ring. 

This can happen with an open neutral on any multiwire branch circuit at any voltage. Because the lamps fire for such a short time in a cyclical way where their duty cycle is much less than 100% in this case they will not burn out instantly. This is not the case for appliances operating at 120/208 with an open neutral or at 120-240. Other loads on the lighting panel like 208 volt single phase HVAC units such as Liebert minimates or large 120/208 photocopy machines might not survive for very long.

There are other reasons to avoid multiwire branch circuits. I stopped allowing them for convenience outlets around 25 years ago but 20 years ago my electricians reported they were getting hit on neutrals. My conclusion was that at harmonic frequencies generated by electronic ballasts, the impedence between the point where the neutral home run is wire nutted to the neutrals for the branch circuits, there is sufficient impedence to ground that a sizeable voltage above grounde can develop. This is where they get hit. 

Just two more neutral wires for three circuits avoids all this plus it avoids the need for super neutrals too. IMO it is well worth it. Perhaps one day the code will catch up to me. It wouldn't be the first time.


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## gold (Feb 15, 2008)

Good post shorty, well explained. 

If the load isnt equal on each phase how does it effect the voltage and time curve on each fixture and each circuit when you remove the nuetral on the same circuit.


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## Bob Badger (Apr 19, 2009)

Shorty Circuit said:


> This can happen with an open neutral on any multiwire branch circuit


Or feeder or service, I guess we should not install those either.



> There are other reasons to avoid multiwire branch circuits. I stopped allowing them for convenience outlets around 25 years ago but 20 years ago my electricians reported they were getting hit on neutrals. *My conclusion was that at harmonic frequencies generated by electronic ballasts, the impedence between the point where the neutral home run is wire nutted to the neutrals for the branch circuits, there is sufficient impedence to ground that a sizeable voltage above grounde can develop. * This is where they get hit.


IMO your conclusion is bogus.



> Just two more neutral wires for three circuits avoids all this plus it avoids the need for super neutrals too.



More labor

More voltage drop

More copper used

Larger conductors needed

Larger pipe sizes

More cost to the customer

Waste of resources



> IMO it is well worth it.


Well hopefully the customer you are working for feels the same, some do, some do not



> Perhaps one day the code will catch up to me. It wouldn't be the first time.


Yeah, 'the code' is just watching what you do.:no:


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## Shorty Circuit (Jun 26, 2010)

Bob Badger said:


> Or feeder or service, I guess we should not install those either.
> 
> 
> 
> ...


"IMO your conclusion is bogus."


That is why you not on my bidder's list. That is also why I would never accept your advice on face value. The added cost of two neutral home runs per three circuts is an excellent investment of insignificant additional cost especially when the overall cost of a job including labor is taken into consideration. The failure of a single neutral during the life of a building which can cause damage to dozens of PCs costs more in direct costs for repair/replacement than all of the added neutrals in the entire building combined would cost. And that doesn't even count the indirect costs when a dozen or more people have to wait around for replacement computers to continue working.

I only wish I knew half as much as you think you know.


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## HackWork (Oct 2, 2009)

I think he's trolling again. How could someone be so far gone from the real world?


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## Shorty Circuit (Jun 26, 2010)

gold said:


> Good post shorty, well explained.
> 
> If the load isn't equal on each phase how does it effect the voltage and time curve on each fixture and each circuit when you remove the nuetral on the same circuit.


The voltage will divide according to the simple application of ohms law. Consider the loop between any two legs of the transformer. Calculate the equivalent parallel impedence of the load between each leg and the neutral point. Then for two legs, these are in series. If they are exactly the same between to legs in a 600 volt/347 transformer, then 600 volts would divide by two and each parallel combination would have 300 across it. But if one is equivalent impedence is higher than the other, the higher impedence will have the greater voltage, including above 347. In the example I gave with the 120/240 volt circuit, if you put say five 60 watt lamps on one hot leg, and one 60 watt lamp on the other, the impedence of the circuit with 5 lamps will be one fifth of the other. Now if you open the neutral, 5/6s of the 240 volts or 200 volts will be across the single lamp. This should burn it out. 

What happened the lamps is that the voltage across one lamp or group of lamps was high enough to fire the lamp. But when it did, the impedence dropped immediatly and so did the voltage across it which is why it went out. It wasn't long enough to cross the time current curve to destroy it. When the voltage dropped across that load, it increased across the lamps that became effectively in series with it and they fired. The process just kept repeating itself. 

The example I gave with the 208vot minimate is wrong. The voltage will remain at 208 volts and it should not be damaged. There is no neutral connection. However, the 120v/208v photocopy machine might be damaged. The machine likely uses the neutral internally for 120volt control voltage possibly through a rectifier. There may be other devices such as motors and relays that operate at 120 volts internally. It isn't clear whether or not it would protect itself if the voltage at that point drifted substantially above 120 volts.


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## Shorty Circuit (Jun 26, 2010)

HackWork said:


> I think he's trolling again. How could someone be so far gone from the real world?


 
HW, I don't hire penguins either. As for BB, if you are going to show up on my job wearing a hat, it had better be a safety hard hat. I wouldn't want anything to accidentally happen to the soft matter underneath it however mushy it is.


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> HW, I don't hire penguins either. As for BB, if you are going to show up on my job wearing a hat, it had better be a safety hard hat. I wouldn't want anything to accidentally happen to the soft matter underneath it however mushy it is.



I guess I won't be on your bidder's list because I spend all my time sticking a screwdriver into energized panels.:huh:


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## Bob Badger (Apr 19, 2009)

Shorty Circuit said:


> That is why you not on my bidder's list.


No, I am not on your bidder list for 100s of reasons, that would not be one of them as it is not 'my company'. 




> That is also why I would never accept your advice on face value.


Right back at you.

Your above conclusion about the shocks ECs where getting suggests you really are not very good at your job.



> The added cost of two neutral home runs per three circuts is an excellent investment of insignificant additional cost especially when the overall cost of a job including labor is taken into consideration.


That is simple not true, properly MWBCs save money and labor.





> The failure of a single neutral during the life of a building which can cause damage to dozens of PCs costs more in direct costs for repair/replacement than all of the added neutrals in the entire building combined would cost.


It would have to be a feeder to damage that many PCs.



> And that doesn't even count the indirect costs when a dozen or more people have to wait around for replacement computers to continue working.


A valid point but the reality of it is often the customer is only concerned with the construction costs of the project.



> I only wish I knew half as much as you think you know.


We both know a lot of things.

Just stop assuming that just because I am an electrician that I don't know some of what you know.


Now back to this.





> I stopped allowing them for convenience outlets around 25 years ago but 20 years ago my electricians reported they were getting hit on neutrals. *My conclusion was that at harmonic frequencies generated by electronic ballasts, the impedence between the point where the neutral home run is wire nutted to the neutrals for the branch circuits, there is sufficient impedence to ground that a sizeable voltage above grounde can develop.* This is where they get hit.



How many volts of potential does it typically take for person to feel a shock? 


BTW, I have never seen an EE that was not anal about their spelling so again I really wonder if you are one?:blink:


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## Mr. Sparkle (Jan 27, 2009)

I'd just like to add that while I have been hit by the neutral of a MWBC in the past, I was but a young grasshopper in the electrical field and only myself and my former "It's only 110 it can't kill you" boss are to blame for the incident.

There are stupid, poorly trained unqualified people in every aspect of employment and no matter how someone designs something you will never make it idiot proof.

With that being said, I love the MWBC and there is a reason they are supposed to be terminated on a multi-pole breaker.


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## millerdrr (Jun 26, 2009)

Mr. Sparkle said:


> I'd just like to add that while I have been hit by the neutral of a MWBC in the past, I was but a young grasshopper in the electrical field and only myself and my former "It's only 110 it can't kill you" boss are to blame for the incident.


:laughing:My boss (and his former boss) were once fond of saying "live wires make good electricians". No idea about the old man, but my boss has backed down from that; every vehicle has a lockout/tagout set, and each employee must watch a video and take an exam on how it works. New employees are not allowed to work on live wires anymore.

Kinda strange, though, when I meet local jmen who say they have been shocked a dozen times in twenty years. In my first six months on the job, I ruined just about every tool in my bag; a reasonable estimate would say I probably took 40 to 50 hits. Macho bravado reigned rampant. 

Saw a guy abandon his scissor lift once and crawl through the rafters, 25' up, to go to a guy on another aisle who had some material he needed. If the lifts didn't go all the way to the ceiling, we would stand on the top rail of the lift, hammering away at Caddy straps.

I quit this company in 2004; returned in 2006. It was radically different back then. The boss is a much-more dedicated professional, these days.:thumbsup:


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## Mr. Sparkle (Jan 27, 2009)

Now that I am the boss I rarely, and I mean rarely work live. I never let my helper touch anything live, ever.

I worked for too many employers in the past that put the $ before the safety of their employees and to be honest I never really looked at it like that until I was in the field for quite some time. Young and dumb......young and dumb....


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## Shorty Circuit (Jun 26, 2010)

Mr. Sparkle said:


> Now that I am the boss I rarely, and I mean rarely work live. I never let my helper touch anything live, ever.
> 
> I worked for too many employers in the past that put the $ before the safety of their employees and to be honest I never really looked at it like that until I was in the field for quite some time. Young and dumb......young and dumb....


 
"Now that I am the boss I rarely, and I mean rarely work live."

When you do on those rare occasions, you are probably in violation of OSHA, NEC, and NESC;

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=25559


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## Shorty Circuit (Jun 26, 2010)

Mr. Sparkle said:


> I'd just like to add that while I have been hit by the neutral of a MWBC in the past, I was but a young grasshopper in the electrical field and only myself and my former "It's only 110 it can't kill you" boss are to blame for the incident.
> 
> There are stupid, poorly trained unqualified people in every aspect of employment and no matter how someone designs something you will never make it idiot proof.
> 
> With that being said, I love the MWBC and there is a reason they are supposed to be terminated on a multi-pole breaker.


"With that being said, I love the MWBC and there is a reason they are supposed to be terminated on a multi-pole breaker"

Have you ever seen a lighting panelboard with multipole breakers feeding MWBC lighting circuits? I haven't and I've seen many hundreds, mabye thousands of them. Same with convenience receptacle MWBCs. The reason you got hit on the neutral is because you had no way to avoid it. Unless you knew which other two circuits to turn off and then actually turned them off, the neutral would still be floating above zero volts, maybe well above it. The added impedence of the ferrous conduit whether it's EMT, RMC, MC, or BX is also the reason we no longer put neutral grounding electrode conductors that bond the transformer neutrals to building steel in steel conduit and why we install bonding jumpers between the wires and the conduit in old ones where they exist. (I usually run mine in PVC if they are exposed and might sustain damage if they are left bare.) The inductive properties of the steel cause it to be a high impedence ground at high frequencies of SMPT generated harmonics. 

So you would expose other electricians to what you know is a potential hazard to save some large corporation that wastes many millions if not billions of dollars on all imaginable kinds of worthless crap a few dollars on a couple of lousy number 12 wires that will go in the same 3/4" conduit with the rest of them. Nice guy.:no: Who are you saving the copper for, China? Oh that's right you're a bidder. So it's not save the trees, save the whales, save the copper, it's save the job. If you don't do it for the cheapest price that's code legal, someone else will. That's why I'm there. I'm just like Barry Cantelope; "I write the specs that makes the whole world sing, I write the specs I write the specs." :yes:


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> ...........Have you ever seen a lighting panelboard with multipole breakers feeding MWBC lighting circuits? I haven't and I've seen many hundreds, mabye thousands of them. .........


How many have you seen that were installed according to the 2008 NEC?:whistling2:


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## Shorty Circuit (Jun 26, 2010)

Bob Badger said:


> No, I am not on your bidder list for 100s of reasons, that would not be one of them as it is not 'my company'.
> 
> 
> 
> ...


"No, I am not on your bidder list for 100s of reasons"

C'mon Bob, do you underestimate my speedreading ability or are you just flattering yourself. I've looked at your old postings and by now it's in the thousands. :laughing:

"it is not 'my company'." 

That one all by itself is reason enough. :tongue_smilie: 

"That is simple not true, properly MWBCs save money and labor."

So does TNT but we don't use it for most indoor demolition work...at least not anymore.:whistling2:

"A valid point but the reality of it is often the customer is only concerned with the construction costs of the project."

That's what I'm there for, to tell him when it is smart to spend extra even if he doesn't absolutely positively legally have to. Read the code, it is not a specification. It says so right up front. First chapter.

"We both know a lot of things."

I hope so.:drink:

"Just stop assuming that just because I am an electrician that I don't know some of what you know."

If you read my first posting when I was a newcomer here, I said I was very greatful to many electricians especially those in local 456 who taught me a great deal, in fact much of my practical knowledge I learned from them. Also some in IUOE local 68. How do you think I got on to you guys?

"How many volts of potential does it typically take for person to feel a shock?"

If you are a really good kisser and wet your lower lip (assuming you haven't worn it down from too much kissin' too many babes ), you should be able to feel a tingle from a new 9 volt battery. OTOH, if you are an old time electrician who's thumb is larger than his big toe from working up a callous because he used it as a 120 volt tester for lo these many years, you might not feel the electric chair.


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> How many have you seen that were installed according to the 2008 NEC?:whistling2:


Only my own. But then I don't allow MWBCs so they look just like the 2005 code.:thumbup:


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> Only my own. But then I don't allow MWBCs so they look just like the 2005 code.:thumbup:



So really your talking through your hat.


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> So really your talking through your hat.


No, I'm talking AT a hat :jester:


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> No, I'm talking AT a hat :jester:



Listen carefully, then. You may learn something. :whistling2:


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> Listen carefully, then. You may learn something. :whistling2:


I've been watching you work in your little corner and I've learned not to stick tools or other metal objects in open live panelboards. 456 taught me not to touch live neutrals in MWBCs. And in the steel mill where I once worked they taught me not to touch nothin'. And so except at home I never do. :thumbsup:


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> I've been watching you work in your little corner and I've learned not to stick tools or other metal objects in open live panelboards. 456 taught me not to touch live neutrals in MWBCs. And in the steel mill where I once worked they taught me not to touch nothin'. And so except at home I never do. :thumbsup:


And since then, you haven't learned a thing. :laughing:


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> And since then, you haven't learned a thing. :laughing:


Oh but I have. Right on this very thread in fact. What is most interesting and instructive about it is not the technical flaw that makes MWBCs so vulnerable to catastrophic failure but that licensed electricians see some of the consequences of that flaw with their own eyes and yet still support that technique because that's what they learned out of a book that was written in other simpler times and for today's world has now got it wrong.

Nobody here has offered a different explanation for how this failure occurred, a plausible alternative that explains the facts we observe in a 16 second clip and so I conclude that they accept this vulnerability and at the same time endorse it. It says much about the electricians themselves and the state of the electrical contracting industry. I hear the message loud and clear and I understand it. How fascinating that in a world where codes are becoming much more restrictive and convoluted, intertwined, difficult to make sense of sometimes, the equipment more complex and demanding, the neglect that industry, utilities, and government have demonstrated in maintaining, improving, replacing, and upgrading their capital electrical plant in recent decades, that the skill to deal with the consequences of this neglect has also declined with it. Fortunately I think there sare still plenty of fine electricians out there. Somewhere. I for one will remain vigilent and selective about who I work with. :detective:


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## Big John (May 23, 2010)

Shorty Circuit said:


> ...What is most interesting and instructive about it is not the technical flaw that makes MWBCs so vulnerable to catastrophic failure but that licensed electricians see some of the consequences of that flaw with their own eyes and yet still support that technique because that's what they learned out of a book....


Try to tone down the condescension just a little. It could be that people who are in favor of the use of mutliwire branch circuits like them because they have a proven record of reliability and cost savings, as determined by our critical thinking skills, not the authors of some book.

Virtually every home in the country is supplied by a MWBC, and most commercial and industrial properties have them. What percentage of failure do you believe is occuring to qualify these as having such a "vulnerability?" It's probably not even 1/500,000.

A lot of MWBC problems occur when people work on them who shouldn't be. That's like saying that if I rebuild my caliper, and my brakes fail because I didn't know what I was doing, then my brakes are "vulnerable to catastrophic failure."

Properly installed, and properly maintained, there is not a thing in the world wrong with MWBCs, and I would reasonably expect them to safely last the life of the building they were put in.

-John


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## Shorty Circuit (Jun 26, 2010)

Big John said:


> Try to tone down the condescension just a little. It could be that people who are in favor of the use of mutliwire branch circuits like them because they have a proven record of reliability and cost savings, as determined by our critical thinking skills, not the authors of some book.
> 
> Virtually every home in the country is supplied by a MWBC, and most commercial and industrial properties have them. What percentage of failure do you believe is occuring to qualify these as having such a "vulnerability?" It's probably not even 1/500,000.
> 
> ...


Is that why 140% and 200% neutrals were invented, because MWBC work so well?

Insofar as the service to a home or a derived source between a transformer and a panel in an industrial or office building is concerned, that is installed once and rarely if ever reworked over its lifetime. But come to think of it, I wonder how many will eventually loosen up at the panelboard and cause problems now that for all practical intents and purposes annual maintenance shutdowns are a thing of the past.

When I built my house about 11 years ago I told the electrical contractor that I didn't want any MWBCs and he said he never installed them anyway. And he was far from the sharpest knife in the drawer.


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## Bob Badger (Apr 19, 2009)

Shorty Circuit said:


> Is that why 140% and 200% neutrals were invented, because MWBC work so well?


Not all loads have harmonic issues.

Beyond that there are few if any documented failures of neutrals due to harmonic currents on otherwise properly designed and installed systems.

What do I mean by 'properly designed?'

I mean not loading every circuit up heavily with non-linear loads.

Many of the jobs we do the EEs have no issues with MWBCs because they do not load each circuit up, they keep the loads to each circuit fairly low, often less than 50% of the circuit rating, the end result is the the same as running a super neutral, the neutral will not be overloaded

Almost all information regarding the need for super neutrals comes from organizations that stand to make money from the installation of those super neutrals.



> Insofar as the service to a home or a derived source between a transformer and a panel in an industrial or office building is concerned, that is installed once and rarely if ever reworked over its lifetime. But come to think of it, I wonder how many will eventually loosen up at the panelboard and cause problems now that for all practical intents and purposes annual maintenance shutdowns are a thing of the past.



The few million installations of services and feeders that have worked fine for many years is pretty indicative of it not being a problem and low failure rate.




> When I built my house about 11 years ago I told the electrical contractor that I didn't want any MWBCs


That is great, you where the person paying the bills so you can ask for and get whatever it is you want. Just as it should be. 



> and he said he never installed them anyway. And he was far from the sharpest knife in the drawer.


That was evident the moment you told us 'he never installed them anyway'. :thumbsup:


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> Oh but I have. Right on this very thread in fact. What is most interesting and instructive about it is not the technical flaw that makes MWBCs so vulnerable to catastrophic failure but that licensed electricians see some of the consequences of that flaw with their own eyes and yet still support that technique because that's what they learned out of a book that was written in other simpler times and for today's world has now got it wrong.


I guess you're the Undisputed King of Electricity, then.



Shorty Circuit said:


> Nobody here has offered a different explanation for how this failure occurred, a plausible alternative that explains the facts we observe in a 16 second clip and so I conclude that they accept this vulnerability and at the same time endorse it.


Undervoltage. How's that grab ya?



Shorty Circuit said:


> It says much about the electricians themselves and the state of the electrical contracting industry. I hear the message loud and clear and I understand it. How fascinating that in a world where codes are becoming much more restrictive and convoluted, intertwined, difficult to make sense of sometimes, the equipment more complex and demanding, the neglect that industry, utilities, and government have demonstrated in maintaining, improving, replacing, and upgrading their capital electrical plant in recent decades, that the skill to deal with the consequences of this neglect has also declined with it. Fortunately I think there sare still plenty of fine electricians out there. Somewhere. I for one will remain vigilent and selective about who I work with. :detective:


Yep, there all plenty of fine electricians out there. Then why the f*&k are you monkeying around with all us numb-nuts then?











All Hail Shorty! All Hail Shorty!
Shorty is OUR GOD!
All Hail Shorty!​


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## Jlarson (Jun 28, 2009)

480sparky said:


> All Hail Shorty! All Hail Shorty!
> Shorty is OUR GOD!
> All Hail Shorty!​


With that I will be going to find a cliff to jump off of now.


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## 480sparky (Sep 20, 2007)

Jlarson said:


> With that I will be going to find a cliff to jump off of now.



Shorty will be happy. One less electrician in the world. :laughing:


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## Jlarson (Jun 28, 2009)

480sparky said:


> Shorty will be happy. One less electrician in the world. :laughing:


Yeah but then I will come back as a ghost and change all the circuits in his facility to MWBCs :laughing::laughing::laughing:


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## Mr. Sparkle (Jan 27, 2009)

Shorty Circuit said:


> "Now that I am the boss I rarely, and I mean rarely work live."
> 
> When you do on those rare occasions, you are probably in violation of OSHA, NEC, and NESC;
> 
> http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=25559


Yep, violated every one of them at one time or another during my stint in the field. I'm not boasting, nor am I proud I am just being honest.



Shorty Circuit said:


> The reason you got hit on the neutral is because you had no way to avoid it. Unless you knew which other two circuits to turn off and then actually turned them off, the neutral would still be floating above zero volts, maybe well above it.


Geez I know why the "grounded conductor" had a load on it, you really did not have to break that down for me.


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> I guess you're the Undisputed King of Electricity, then.
> 
> 
> 
> ...


"Undervoltage. How's that grab ya?"

Doesn't sound plausible. Give me an explanation of how that works. The voltage fluctuates at just the right level for the lights to go on and off in flashes and every time for just a fraction of a second? Hmm, doesn't sound quite plausible to me.

"Yep, there all plenty of fine electricians out there. Then why the f*&k are you monkeying around with all us numb-nuts then?"

Isn't it obvious? For the yuks. :laughing:


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## Big John (May 23, 2010)

Mr. Sparkle said:


> ...Geez I know why the "grounded conductor" had a load on it, you really did not have to break that down for me.


 Yeah, Shorty seems to have a pension for explaining things that are painfully obvious.:whistling2:

-John


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> Doesn't sound plausible. Give me an explanation of how that works. The voltage fluctuates at just the right level for the lights to go on and off in flashes and every time for just a fraction of a second? Hmm, doesn't sound quite plausible to me.


I would try to explain it to you, but you will simply dismiss it, no matter how factual and true it is.



Shorty Circuit said:


> Isn't it obvious? For the yuks. :laughing:


So all those fine, outstanding, superb and world-class electricians that are on your bidding list don't have the mental capacity to understand MWBCs, huh?


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> I would try to explain it to you, but you will simply dismiss it, no matter how factual and true it is.
> 
> 
> 
> So all those fine, outstanding, superb and world-class electricians that are on your bidding list don't have the mental capacity to understand MWBCs, huh?


Yes, they not only know Ohm's law, they can apply and solve Kirchoff's equations. Believe it or not, that's all it takes. Now you don't even have to go to a library anymore, you can study them on line.


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> Yes, they not only know Ohm's law, they can apply and solve Kirchoff's equations. Believe it or not, that's all it takes. Now you don't even have to go to a library anymore, you can study them on line.



But according to you, they're too dumb to understand MWBCs.


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> But according to you, they're too dumb to understand MWBCs.


I never said that. I said they run the gammut from outstanding to people I would not want to see on even the simplest job. I also said that I'd learned a great deal from the best of them, notably out of local 456. More than one literally saved my life because of their expert knowledge. OTOH, there were some who left jobs in a condition that might have caused a fatality.


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## HackWork (Oct 2, 2009)

Shorty Circuit said:


> I never said that. I said they run the gammut from outstanding to people I would not want to see on even the simplest job. I also said that I'd learned a great deal from the best of them, notably out of local 456. More than one literally saved my life because of their expert knowledge. OTOH, there were some who left jobs in a condition that might have caused a fatality.


456 is a bunch of 2 bit hacks. You could tell them I said so too.


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> I never said that. ........


Yes you did, just not in those words.



Shorty Circuit said:


> .........So you would expose other electricians to what you know is a potential hazard .........


In other words, you don't think the electricians you hire are capable of recognizing what you (and apparently only you) perceive as a hazard.







Shorty Circuit said:


> ...............That is why you not on my bidder's list. ...............


BTW, since when do EEs hire the ECs?


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> Yes you did, just not in those words.
> 
> 
> 
> ...


"Yes you did, just not in those words."

So you admit you've twisted my words around to fit what you wanted them to say. Figures. Your complexes are not my problem, they are yours.

"In other words, you don't think the electricians you hire are capable of recognizing what you (and apparently only you) perceive as a hazard."

I make my decisions and judgements based on my knowlege and understanding of NEC and a lot more. My designs comply with the code but are sometimes much more restrictive. There is nothing in the code that says for example that you have to use MWBCs, it is just permitted, not required. And I remind you that I only eliminated MWBCs on lighting circuits when the electricians complained and reported to me they were getting hit on neutrals. Up to that point I never suspected it or even thought about it.

I don't always agree with the code. For example, I didn't have to wait for the 2008 code to change to know it was a dumb idea to connect more load on a generator than it is capable of supporting because those loads are critical and sooner or later when it is least welcome those diversity calculations will turn out dead wrong and it will trip out. 

"BTW, since when do EEs hire the ECs?"

In most of my jobs in the past I worked for the owner usually in a facilities department. I could wear any number of hats including design engineer, project manager, construction manager, construction inspector and any combination or all of them at the same time and not for just electrical projects but for any and all trades. Usually in large companies management is just too happy to have someone who gets the jobs done and makes problems go away so that they don't have to hear about them. If someone has a track record of success at it, they just let them do their job and leave them alone. That left me free to think about much more than first cost or just the immediate needs of the project at hand. Long term planning and implimentation by designing and building for future unanticipated needs was value added to all my projects when it was possible. In the long run it was the cheapest way to do jobs. First cost is usually the least important factor over the life of a building and what is installed in it.


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> .......... And I remind you that I only eliminated MWBCs on lighting circuits when the electricians complained and reported to me they were getting hit on neutrals............



So you admit your electricians are working live? And that they STILL don't understand MWBCs?

In short, you're throwing out a perfectly valid and safe method because someone else is stupid.

So are you going to not allow ladders on jobs as soon as someone falls off one? If someone cut themself with strippers, well, let's just not allow strippers on the job. 

Yeah, let's just disallow everything that anyone has ever gotten hurt with. Maybe you should go work for OSHA.


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> So you admit your electricians are working live? And that they STILL don't understand MWBCs?
> 
> In short, you're throwing out a perfectly valid and safe method because someone else is stupid.
> 
> ...


"So you admit your electricians are working live?"

You just don't seem to get it. It's not alive when each lighting circuit has its own netural. When the hot leg is switched off, there is no neutral current in that circuit they are working on when there's no MWBC. That's the whole point of it. Which part didn't you understand.


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## 480sparky (Sep 20, 2007)

Shorty Circuit said:


> .......You just don't seem to get it. It's not alive when each lighting circuit has its own netural. When the hot leg is switched off, there is no neutral current in that circuit they are working on when there's no MWBC. That's the whole point of it. Which part didn't you understand.



Sigh. What part of THIS ( and these are YOUR words, not mine!) don't you understand?:




Shorty Circuit said:


> ........ And I remind you that I only eliminated MWBCs on lighting circuits when the electricians complained and reported to me they were getting hit on neutrals. ..........


You don't seem to even comprehend your own words. How sad.


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## Shorty Circuit (Jun 26, 2010)

480sparky said:


> Sigh. What part of THIS ( and these are YOUR words, not mine!) don't you understand?:
> 
> 
> 
> ...


I found that the best part about hitting your head against a brick wall is that it feels so good when you stop. That's the point I'm at here. 

BTW, hot work is still legal in some circumstances. I gave a link to OSHA's defining document which explains what is meant by the jargon "continuous industrial process" and under what restrictions and circumstances hot work is still allowed. However, it used to be allowed much more commonly. IBEW journeymen used to brag that they received 3 years of training performing supervised hot work in their federally approved five year apprenticeship program. No electrician ever performing hot work on any project I ran ever received an injury (except for getting zapped on lighting neutrals.) I assume that NEC, NESC, and OSHA became much more restrictive due to a large number of reported injuries when unqualified people got hurt or killed because they didn't know when and how to perform hot work safely. This is only one of the reasons I get extremely conccerned when non union electricians I'm not familiar with show up on a job. Even if the owner and one or two of his men are competent, I have no idea what else might walk on the job with them. But these days it's usually not up to me. I haven't been running projects in awhile. That could change though.


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