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A
Anonymous
Unregistered
Can anybody reference in the NEC where it says how many receptacles are allowed on a branch circuit. Our general rule of thumb here in PA is 7 per circuit. However the debate is ongoing at the local electrical distributor/coffee shop. (As I am sure that everyone experiences.)

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Joined: Apr 2001
Posts: 449
F
Member
If you're talking about residential, there is no NEC limit. I've always followed the common sense rule of 8 on a 15A circuit and 10 on a 20A circuit in residential. It gives you room to add on to a circuit later. If it's a commercial setting you would figure 180VA per so it would be 10 on a 15A @ 120V and 12 on a 20A @ 120V

A
Anonymous
Unregistered
I agree with you on both issues. We here in PA dont understand how an inspector can not pass an installation stating that there are too many recepts on a circuit since the code does not specify it. Is this left up to the inspector and his interpretation?

Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
Blue,

If he can't write down or tell you the code section, it isn't a violation. Inspectors aren't allowed to make up their own rules. If the NEC is adopted by law or ardinance, any exceptions or additions must also be enacted by a legislative body.

Per code- residential, as many as you want, Commercial- 10 on a 15 amp circuit, 13 on a 20 amp circuit.


Few things are harder to put up with than the annoyance of a good example.
Joined: Dec 2001
Posts: 5
M
Junior Member
I would agree with Tom, however, with one added note. Since, per 220.3(B)(10), the load calculations of general-use receptacle outlets for dwelling units are included in the general lighting load calculations from table 220.3(A), which is based on 3VA per sq. ft. The load (number of receptacles) shall be evenly proportioned among the multioutlet branch circuits within the panelboard, per 210.11(B). So if you had a branch circuit that was not evenly proportioned as compared to the other receptacle outlet branch circuits in the panelboard, the inspector would be correct in not passing the installation.

Joined: Oct 2000
Posts: 5,392
S
Member
mdsmith

what if you wired receptacle circuits exclusive from lighting circuits....

just a wha-if..
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Joined: Jan 2001
Posts: 1,044
Tom Offline
Member
The number of receptacles on a general purpose lighting circuit in a house doesn't have much to do with evenly proportioning the load. This was already taken care of in the watts per square foot calculation and the calculation to determine the minimum number of circuits that are needed. Since receptacles are not a load, there is no limit to how many on a general purpose lighting circuit. If an inspector tried to cite me on not balancing the load because one circuit had many more receptacles than another, we'd be into the appeal process in short order.

Tom


Few things are harder to put up with than the annoyance of a good example.
A
Anonymous
Unregistered
My sentiments exactly. I do a lot more light industrial and commercial work than residential, so my my code knowledge is more geared toward to those areas. This came up on a house addition in which the inspector would not pass the rough-in until 1 receptacle was removed from the circuit. The "show me the code" attitude came into play and another inspector was called who subsequently passed the installation.

Joined: May 2001
Posts: 176
W
Member
As many of you know, I am an electrical designer, industrial/commercial mostly. We usually do not load our circuits to over 80% unless the breaker is rated for 100% load. Most panelboard breakers are not 100% rated. Therefore, on a 20 amp breaker, we use 20*120*.8=1920watts per circuit as the maximum, which equals 10.(66) receptacles. Normally we use seven (7) as our target loading . This is for commercial/industrial work. In many areas of commercial/industrial work, you have to consider the receptacle as having a computer (300 watts) and a printer HP= ~10amps). That means one (1) circuit per receptacle, unless you can come up with a printer demand factor. We usually use two and no more than three recptacles per 20 amp circuit for these applications. This will happens in office areas where every occupant wants a printer. In my office, we have one printer for about 30 persons. Needless to say, most are on a branch circuit to themselves because of high demand.
For residential, my code instructor taught us there is no limit to the number of recptacles on a branch circuit. However, with the increased use of computers (and severs)in the home, I believe that should change in the very near future. Everyone has to have access to the NET to check their email.
Just another thought on this subject.

Joined: Dec 2001
Posts: 5
M
Junior Member
sparky,

My reference to 220.3(B)(10) and table 220.3(A) was not to imply that general-use receptacles would necessarily have to be wired to lighting circuits for the provisions of 210.11(B) to apply, but that since the outlets specified in 220.3(B)(10), (1), (2), and (3) are included in the sq. ft. general lighting load calculations of 220.3(A) the provisions of 210.11(B) would, in fact, apply regardless. Great discussion!

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