Use of SEC Aluminum Wire in Dwelling (also applies to SEC Copper Conductors)

From: Ron Chilton [rchilton@ncdoi.net]
Sent: Friday, December 12, 2008 9:55 AM
To: Bill Newns
Subject: RE: SEC 334.80

Hi Bill,
I don’t think I answered this question yet, I apologize.

If Table 310.15(B)(6) applies to a main power feeder, there is no temperature limitation mentioned in that Table. There must not be but one feeder that supplies the entire load of the dwelling in order to use that Table. Note that 4/0 AL conductor, with an allowable ampacity per Table 310.15(B)(6) of 200 amps, is only rated at 150 amperes in Table 310.16, at 60-degrees. The diversity built into the calculation is the reasoning behind this Table allowing to seemingly overload the conductors. If a Meter-Main combo is used with feed-through lugs, no circuits may be fed from that outside panel to the dwelling and still use Table 310.15(B)(6).

If the feeder is not the main power feeder, then Table 310.16 must be used and the 60-degree ampacity must be adhered to.

Hope this helps, if further assistance is needed, please contact me.
Thanks,

Ron
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From: Bill Newns [mailto:bnewns@co.currituck.nc.us]
Sent: Wednesday, December 10, 2008 3:55 PM
To: Ron Chilton
Subject: SEC 334.80

Ron,

I have a house with a meter with a service disconnect outside with SER cable running from the disconnect to the inside panel box, does article 334.80 apply to the wire from the disconnect to the sub panel box inside the house for derating to 60 degree?

Thanks

Bill Newns