Feeder Calculation for an individual unit of a Multifami

[kaltbier]

This is actually based on Example D4(a)
I have figured out how to calculate the total loads easily enough for both gas range and electric range units, but now I am looking at 230.79. I don't know whether to make the minimum OCPD 60A [230.79(D)] or 100A [230.79(C)]. I am using the Standard Method.

 

[charlie b]

Re: Feeder Calculation for an individual unit of a Multifami

Are you saying that the ?multi-family dwelling? does not have a single service (i.e., with feeders to each individual unit, and with the N-G bond only at the service), and that each unit has a separate ?service? (i.e., with an N-G bond at each unit?s service equipment)? If that is the case, and it would surprise me if it were, then I would say that you are into 230.79(C).

But if this is a single building with one service, and if each unit is supplied by a ?feeder,? and not by a separate ?service,? then I think you are not in 230 at all. All other considerations aside, however, I would prefer to make the design choice (i.e., not necessarily a code requirement) of giving any single dwelling unit at least 100 amps.

 

[kaltbier]

Re: Feeder Calculation for an individual unit of a Multifami

Example D4(a) starts like this:
A multifamily dwelling has 40 dwelling units.
Meters are in two banks of 20 each with individual feeders to each dwelling unit.

Refering to the second part of your reply, what states that "each supply through a meter is a feeder and then I am not in 230 at all" is actually a very thoughtful statement. The repercussions take me, then, to 215.2(A)(4), which takes me to Table 310.15(B)(6), which takes us back to your design preference of a 100-A panel for each individual dwelling unit of this multifamily dwelling. Thanks for the reply.