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Number of outlets and lights on a 15-amp breaker

Posted by sailor86 (My Page) on
Sun, Dec 5, 10 at 11:55

It's been a while since I wired an entire circuit in a house. What's the max number of things that can be wired into a 15-amp breaker?


Follow-Up Postings:

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RE: Number of outlets and lights on a 15-amp breaker

For most of your circuits, there's no specified limit in the code.


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RE: Number of outlets and lights on a 15-amp breaker

There is no limit, however per code, load cannot exceed %80 of the breaker size. In this case: 12 amps


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RE: Number of outlets and lights on a 15-amp breaker

"There is no limit, however per code, load cannot exceed %80 of the breaker size. In this case: 12 amps"

Since a residential receptacle has no identified load you can place as many as you want on a single circuit.

Commercial locations are required to use 180 V-A per receptacle when sizing circuit capacity.


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RE: Number of outlets and lights on a 15-amp breaker

For the combination of general lighting and general use receptacles the code does limit, in a round about way, a 15amp circuit to 600 square feet of dwelling. While at the same time there would be no limit on the number of general use receptacles you could install on this circuit. This may not always be a practacle limit and could result in tripped breakers on a regular basis, but the code is only concerned with the safety of an installation. The practicality or convenience of the installation is a design issue.


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RE: Number of outlets and lights on a 15-amp breaker

If you're alluding to the 1va/sq ft lighting load rule, you're wrong there as well. It doesn't apply to dwellings either.


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RE: Number of outlets and lights on a 15-amp breaker

Ron
In light of the National Electric Code's article 220.82(B)(1) which says (33 volt-amperes/m2 or 3 volt-amperes/ft2 for general lighting and general-use receptacles. The floor area for each floor shall be calculated from the outside dimensions of the dwelling unit.) please explain how I am wrong there as well, and also enlighten me on what else I am wrong about, as I am baffled as to what you are alluding to.
Thanks


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RE: Number of outlets and lights on a 15-amp breaker

Well fir st off, that's the optional section, an alternate way of computing the service size, so it doesn't universally apply. What you really want is 220.12, for load computation, but even that doesn't tell you squat about receptacles (or their branch circuits). The load calculation for the service is in 220.14 (J).


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RE: Number of outlets and lights on a 15-amp breaker

Ron
Not only does 220.12 say 3va/sq. ft. for dwellings but 220.14(J) says all general-use receptacle outlets of 20-ampere rating or less are included in the general lighting calculations of 220.12.

Try again?


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