Bedroom outlets o.k. to serve other outlets

[scwirenut]

Re: Bedroom outlets o.k. to serve other outlets

lets not forget the inspectors intent with this foolish 3va call. he is trying to make up his own code so the electricians wont put 5 br's on 1 afci, because they are to cheap from undercutting to use more. i see his intent, however he is WRONG, if he wants it this way, he must provide you a written amendment to nec (that is if they have even adopted it)

 

[eprice]

Re: Bedroom outlets o.k. to serve other outlets

Originally posted by charlie b:
I think your AHJ is wrong.

I may not garnish a great deal of support for the following statement, but I submit that the "3 VA per square foot" is not related in any way to the amount of load you are permitted to connect to a 15 amp branch circuit. It's not a bad rule of thumb for designing a house, but it is not a code requirement.

The "3 VA per square foot" is only used in the service or feeder calculation process. You use that number to make sure you are giving the house enough power to handle its minimum needs. But there is nothing in the code language that says a 15 amp branch circuit can not be used to cover more than 600 square feet of living space.

I too think the AHJ is wrong. In the case described in the OP, I think he is going far beyond what the code intends.

However, I have to respectfully disagree a bit with what Charlie is saying as well. Yes, Article 220 is about calculations, but 210.11(A) requires a minimum number of circuits. This minimum is based on those calculations. Being very simplistic, if I had a 1200 sq. ft. home and I intended to use 15 amp circuits, I would need two of them. 210.11(B) requires the load to be evenly proportioned among the branch circuits. One way to accomplish that would be to arange for the circuits to serve roughly equal areas. Charlies example using 4 circuits to supply 4 bedrooms would be another, although unorthodox, way to do it.

If there were a situation where one 15 amp circuit serves a 1,000 sq. ft. area, then I think that would be a violation. Either there are not enough circuits (violation of 210.11(A)) or the particular circuit is serving more load than the other circuits (violation of 210.11(B)).

 

[charlie b]

Re: Bedroom outlets o.k. to serve other outlets

I respectfully disagree right back at ya.

210.11(B) only applies when the load is calculated on a VA per square foot basis. The service calc process requires me to allow for a minimum amount of load, and it gives the minimum in terms of VA per square foot. That just forces me to have a minimum size of service. It does not require me to size the branch circuits on the same basis.

Let's talk about an 1800 square foot residence. It could have a large living/dining room (i.e., a "great room"). Let's say it is 30 x 30 (900 square feet), with a great deal of window space. I can take advantage of day-lighting, and reduce the amount of light fixtures to, let us say, five 100 watt fixtures. I can feed that with a single 15 amp circuit, and toss in a few LR receptacles as well, despite the fact that the room is over 600 square feet. I am not calculating the load on a "per square foot" basis, I am calculating the load on a "per fixture or per outlet" basis. I can then feed the lights and receptacles for the rest of the house (not including the laundry or SA circuits) with two other 15 amp circuits. I can make the three 15 amp circuits approximately equally loaded. Thus, I would have one circuit feeding 900 square feet, and the other two circuits feeding 450 square feet each. No violation.