NEC 310.12(A) One-Family Dwelling Service Conductors & Feeders

[wwhitney]

Why then is the 100% factor mentioned in 310.12(B) with regards to a dwelling feeder? In what circumstance would the 100% of the load apply to a dwelling feeder?

Any multifamily building (even a duplex) will likely have a service that supplies multiple dwelling units, and that service does not meet the requirements of 310.12(A). But then if a dwelling unit has a subpanel in it that supplies all the dwelling unit's loads, the feeder to that subpanel would satisfy 310.12(B), assuming it is rated between 100A and 400A.

Cheers, Wayne

 

[ICE]

The light is on. Thanks for that.

 

[jar546]

The light is on. Thanks for that.

The lights are on, but you're not home
Your mind is not your own

 

[ICE]

The lights are on, but you're not home
Your mind is not your own

Watching that video reminds me of an office where one guy did all of the hiring.

 

[steveray]

This was a problem for 100A exterior main disco "services" here where they would put the main outside and run what they normally would for a service sized SER in and then they would have to put a smaller main breaker in as the feeder and service ampacities were/ are different....