Which Table?

[George Stolz]

Re: Which Table?

Originally posted by websparky:
George,

How many "main" disconnects are there in any given dwelling unit?

At my house? I have a 200 amp 3R MDP with feeders for:
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• <font size="2" face="Verdana, Helvetica, sans-serif">Well pump 240V BC</font>
• <font size="2" face="Verdana, Helvetica, sans-serif">Pole light MWBC</font>
• <font size="2" face="Verdana, Helvetica, sans-serif">Pole receptacle MWBC</font>
• <font size="2" face="Verdana, Helvetica, sans-serif">Barn feeder</font>
• <font size="2" face="Verdana, Helvetica, sans-serif">Crawlspace Lights & Outlet</font>
• <font size="2" face="Verdana, Helvetica, sans-serif">Dwelling Unit Feeder</font>

<font size="2" face="Verdana, Helvetica, sans-serif">I would say I have 6 main disconnects, with the potential (in my case) for 20.

Of all these, only the last one qualifies to use 310.15(B)(6).

 

[don_resqcapt19]

Re: Which Table?

Bob,

But are they all 'main' feeders?

Yes, per the defintion of "main power feeder" in the section.

For application of this section, the main power feeder shall be the feeder(s) between the main disconnect and the lighting and appliance branch-circuit panelboard(s).

Any feeder between the main disconnect and the lighting and appliance branch circuit
panelboards(s) are main power feeders per the code. There is nothing in the code rule that says that this feeder must carry any specific part of the dwelling unit load, let alone a major (main) part of that load. This is a very poorly written section and that is why it is always a subject of discussion. I do agree that the reduced size conductors cannot be used to feed an outbuilding, because that is not a dwelling unit.
Don