# Is this Code compliant



## HARRY304E (Sep 15, 2010)

I have a single phase residential service install with 200 amp meter enclosure fed with #2/0 per T310.15(B)(6). The first panel has dual lugs on the main's20 amps Breaker on the line side and feeds an adjacent second 200 amp main breaker panel. Each panel is rated at 200 amps and has a 200 amp main. Calculated load is less than 200 amps. Are the #2/0's SEC,s protected and compliant ??

What Article in the Nec states that you can't do that?


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## doubleoh7 (Dec 5, 2009)

HARRY304E said:


> I have a single phase residential service install with 200 amp meter enclosure fed with #2/0 per T310.15(B)(6). The first panel has dual lugs on the main's20 amps Breaker on the line side and feeds an adjacent second 200 amp main breaker panel. Each panel is rated at 200 amps and has a 200 amp main. Calculated load is less than 200 amps. Are the #2/0's SEC,s protected and compliant ??
> 
> What Article in the Nec states that you can't do that?


 I assume that the conuctors are copper? I thought it was 3/0 copper for a 200 amp service, but I dont have my code book in front of me, I'm in bed. I use 4/0 al for 200 amp services. How far away is the second panel? You said adjacent, so I assume it is right next to the first panel. And is the first panel right where the conductors enter the home?

Could you use a 100 amp subpanel fed fromm a 100 amp DP breaker for your second panel? I know that QO is available in 32 space.

If I understand you, you could actually draw 400 amps on your service conductors because the panels are split on the line side. Not good. Also, what about the 6 throws rule, would it be OK since you only have 2 - the 2 mains.

Like I said, I dont have my code book in front of me, but That is a no-no. What you have is a 400 amp service on 2/0 copper. And you have 2 mains.


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## McClary’s Electrical (Feb 21, 2009)

doubleoh7 said:


> I assume that the conuctors are copper? I thought it was 3/0 copper for a 200 amp service, but I dont have my code book in front of me, I'm in bed. I use 4/0 al for 200 amp services. How far away is the second panel? You said adjacent, so I assume it is right next to the first panel. And is the first panel right where the conductors enter the home?
> 
> Could you use a 100 amp subpanel fed fromm a 100 amp DP breaker for your second panel? I know that QO is available in 32 space.
> 
> ...


Two panels don't make it a 400. 

I just finished wiring a new house that had (2) 200 amp service panels, (2) 200 amp sub panels, (2) 100 amp subpanels, and (2) 60 amp sub panels. 

Does that make mine 1100 amp service?


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## wayne g (Nov 28, 2010)

You said the 1st panel has dual lugs, is there one meter can or more ? Is this a single family. 2/0 AL would give you 200 amps in residential.
Whats the reason for the second panel ? :001_huh:


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## HARRY304E (Sep 15, 2010)

wayne g said:


> You said the 1st panel has dual lugs, is there one meter can or more ? Is this a single family. 2/0 AL would give you 200 amps in residential.
> Whats the reason for the second panel ? :001_huh:


200 amp meter before the first panel. 2/0 copper.
single family. 

Whats the reason for the second panel?:001_huh: ..More circuits


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## jwjrw (Jan 14, 2010)

HARRY304E said:


> 200 amp meter before the first panel. 2/0 copper.
> single family.
> 
> Whats the reason for the second panel?:001_huh: ..More circuits



I looked at a house last week with (3 ) 200 amp panels with mains in each. I figured the builder had them and used them. One was a feed thru panel (trailer panel) and it fed the inside panel. Legal but a waste of money IMO.


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## Dennis Alwon (May 9, 2009)

Harry have you been over to the Mike Holt forum Thread. This exact question was asked 2 days ago-- very odd.. I say it is a sucky setup but I believe it to be code compliant. Service entrance conductors must satisfy the "nearest the point of entry" rule set forth in 230.70(A)(1). That is where you may fail.


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## jwjrw (Jan 14, 2010)

Dennis Alwon said:


> Harry have you been over to the Mike Holt forum Thread. This exact question was asked 2 days ago-- very odd.. I say it is a sucky setup but I believe it to be code compliant. Service entrance conductors must satisfy the "nearest the point of entry" rule set forth in 230.70(A)(1). That is where you may fail.



I took it as the meter and both panels were outside.:001_huh:


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## Dennis Alwon (May 9, 2009)

jwjrw said:


> I took it as the meter and both panels were outside.:001_huh:


Perhaps but perhaps not. Either way it is still an interesting poser.


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## HARRY304E (Sep 15, 2010)

Dennis Alwon said:


> Harry have you been over to the Mike Holt forum Thread. This exact question was asked 2 days ago-- very odd.. I say it is a sucky setup but I believe it to be code compliant. Service entrance conductors must satisfy the "nearest the point of entry" rule set forth in 230.70(A)(1). That is where you may fail.



Yes i thought it was a great Question so i wanted to see what the guys thought over here.

There Does not seem to be a good answer In the code for this one.

It is a crazy set up


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## doubleoh7 (Dec 5, 2009)

mcclary's electrical said:


> Two panels don't make it a 400.
> 
> I just finished wiring a new house that had (2) 200 amp service panels, (2) 200 amp sub panels, (2) 100 amp subpanels, and (2) 60 amp sub panels.
> 
> Does that make mine 1100 amp service?


 
Read the original post carefully. He says thet he is splitting the two panels on the LINE SIDE. He could draw 400 amps on a 200 amp service. That is what I am seeing if I understand his post correctly.


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## Dennis Alwon (May 9, 2009)

doubleoh7 said:


> Read the original post carefully. He says thet he is splitting the two panels on the LINE SIDE. He could draw 400 amps on a 200 amp service. That is what I am seeing if I understand his post correctly.


That is correct but it is still compliant since the calculated load is under 200 amps.


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## doubleoh7 (Dec 5, 2009)

Dennis Alwon said:


> That is correct but it is still compliant since the calculated load is under 200 amps.


 
I still would not want to do it. Who knows what may be added later. If I was doing it, I would use a 100 amp MLO panel for the second panel fed from a 100 amp dp breaker in the first panel. Or, I would add a 200 amp main breaker below the meter on the outside.:thumbsup:


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## Dennis Alwon (May 9, 2009)

doubleoh7 said:


> I still would not want to do it. Who knows what may be added later. If I was doing it, I would use a 100 amp MLO panel for the second panel fed from a 100 amp dp breaker in the first panel. Or, I would add a 200 amp main breaker below the meter on the outside.:thumbsup:


The op is not asking what you would do, he is giving a hypothetical situation and asking if it is legal.

If I have a 200 amp main lug panel at my main service and I add 2 breakers to disconnect the entire house and the load is just under 200 amps, then what is to stop the next person from adding another one or two 100 amp breakers-- remember 6 disconnects is legal and we will only have 2/0 feeding the panel- no main. It isn't any different then that, IMO.


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## nitro71 (Sep 17, 2009)

Compliant in my eyes. The only thing I can think of is that you might have to size the feeder to the second panel per table 310.16 and not 310.15(B)(6). That's nit picking and I think this is a good install.


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## McClary’s Electrical (Feb 21, 2009)

nitro71 said:


> Compliant in my eyes. The only thing I can think of is that you might have to size the feeder to the second panel per table 310.16 and not 310.15(B)(6). That's nit picking and I think this is a good install.


 

Good point, under '08 you're right.


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## Dennis Alwon (May 9, 2009)

mcclary's electrical said:


> Good point, under '08 you're right.


Why would that be. The wire from panel 1 to 2 is a service conductor not a feeder and if it were then 215.2 (A)(3) would be applicable.


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## sparks134 (Jan 30, 2009)

nitro71 said:


> Compliant in my eyes. The only thing I can think of is that you might have to size the feeder to the second panel per table 310.16 and not 310.15(B)(6). That's nit picking and I think this is a good install.


When is it ok to use table 310.15(B)(6)... Now I'm really confused. I thought that table was only for services and feeders. Can this table be used for subpanel too???


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## Dennis Alwon (May 9, 2009)

sparks134 said:


> When is it ok to use table 310.15(B)(6)... Now I'm really confused. I thought that table was only for services and feeders. Can this table be used for subpanel too???


No, it cannot be used for sub panels. In the op's question these panels are service panels.


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## McClary’s Electrical (Feb 21, 2009)

Dennis Alwon said:


> Why would that be. The wire from panel 1 to 2 is a service conductor not a feeder and if it were then 215.2 (A)(3) would be applicable.


 
Yes, but that wouldn't change the fact that you can't use 310.15 (b) (6) under 08 unless it carries the entireload of the dwelling.


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## HARRY304E (Sep 15, 2010)

mcclary's electrical said:


> Yes, but that wouldn't change the fact that you can't use 310.15 (b) (6) under 08 unless it carries the entireload of the dwelling.


Remember The first panel has dual lugs on the main's20 amps Breaker on the line side and feeds an adjacent second 200 amp panel main breaker ,. so eather way it is still a service entrance conductor.


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## McClary’s Electrical (Feb 21, 2009)

HARRY304E said:


> Remember The first panel has dual lugs on the main's20 amps Breaker on the line side and feeds an adjacent second 200 amp panel main breaker ,. so eather way it is still a service entrance conductor.


 

Yes, but it does not carry the entire load of the house, so that chart can't be used.


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## Dennis Alwon (May 9, 2009)

mcclary's electrical said:


> Yes, but that wouldn't change the fact that you can't use 310.15 (b) (6) under 08 unless it carries the entireload of the dwelling.


The conductors must carry the entire load of the house. It does-- it is tapped to both panels. Now are you saying that the wire that is tapped to the first panel must be larger than the service conductor????


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## BuzzKill (Oct 27, 2008)

doubleoh7 said:


> I still would not want to do it. Who knows what may be added later. :


Rare to say I would worry about future installs but in this case, I agree with double O


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## Dennis Alwon (May 9, 2009)

Is this not what the op states. Instead of the tap I show he has the service conductor spliced thru double lugs before the main. How is this not carrying the entire load of the dwelling?


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## Shockdoc (Mar 4, 2010)

doubleoh7 said:


> I assume that the conuctors are copper? I thought it was 3/0 copper for a 200 amp service, but I dont have my code book in front of me, I'm in bed. I use 4/0 al for 200 amp services. How far away is the second panel? You said adjacent, so I assume it is right next to the first panel. And is the first panel right where the conductors enter the home?
> 
> Could you use a 100 amp subpanel fed fromm a 100 amp DP breaker for your second panel? I know that QO is available in 32 space.
> 
> ...


3/0cu is commercial......2/0 cu is fine for residential 200, I even cheat sometimes and use 2/0 cu on commercial.


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## McClary’s Electrical (Feb 21, 2009)

nitro71 said:


> Compliant in my eyes. The only thing I can think of is that you might have to size the feeder to the second panel per table 310.16 and not 310.15(B)(6). That's nit picking and I think this is a good install.


 



Dennis Alwon said:


> The conductors must carry the entire load of the house. It does-- it is tapped to both panels. Now are you saying that the wire that is tapped to the first panel must be larger than the service conductor????


 
So far, I agree with Nitro, but I need to see the wording of '08. I don't have it, I'm on '05 Would you post 310. 15 (b) (6) out of the '08 please?


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## McClary’s Electrical (Feb 21, 2009)

Actually the last two sentences of 310.15 (B) (6) did notchange so I (now) think you are right.


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## jwjrw (Jan 14, 2010)

For 2011.

(7) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services
and Feeders. For individual dwelling units of onefamily,
two-family, and multifamily dwellings, conductors,
as listed in Table 310.15(B)(7), shall be permitted as
120/240-volt, 3-wire, single-phase service-entrance conductors,
service-lateral conductors, and feeder conductors
that serve as the main power feeder to each dwelling unit
and are installed in raceway or cable with or without an
equipment grounding conductor. For application of this section,
the main power feeder shall be the feeder between the
main disconnect and the panelboard that supplies, either by
branch circuits or by feeders, or both, all loads that are part
or associated with the dwelling unit. The feeder conductors
to a dwelling unit shall not be required to have an allowable
ampacity rating greater than their service-entrance conductors.
The grounded conductor shall be permitted to be
smaller than the ungrounded conductors, provided the requirements
of 215.2, 220.61, and 230.42 are met.


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## firelient (Dec 15, 2010)

The 2/0 wire has the potential of having 400 amps on it if you would load both panels, it looks to me like.


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## HARRY304E (Sep 15, 2010)

firelient said:


> The 2/0 wire has the potential of having 400 amps on it if you would load both panels, it looks to me like.


The Calculated load is less than 200 amps.

Welcome to the forum


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## Dennis Alwon (May 9, 2009)

firelient said:


> The 2/0 wire has the potential of having 400 amps on it if you would load both panels, it looks to me like.


Yep, that is why no one likes the install but whenever you use the 6 disconnect rule instead of a main breaker there is that potential to go over the limit of the conductor. It is legal.


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