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#130742 - 12/01/06 05:46 AM Max current load
JakeJ1 Offline
Junior Member

Registered: 03/24/05
Posts: 3
Loc: charleston SC USA
Not necessarily an NEC/code question. If I have two 10Awg circuits using 10/3 with ground MC cable and I put these together in parallel, what is the max current load that this will support?

#130743 - 12/01/06 07:13 AM Re: Max current load
sabrown Offline

Registered: 12/12/02
Posts: 297
Loc: Ogden, Utah, USA
Article 310.4 discusses conductors in parallel. Using the information there we find that paralleling #10 is only allowed in limited circumstances and based on Exception 1 (b) we find that parallel #10 (referring to table 310.16) carry 30 amps at 60 degree C (no increase in ampacity).

#130744 - 12/01/06 08:25 AM Re: Max current load
JakeJ1 Offline
Junior Member

Registered: 03/24/05
Posts: 3
Loc: charleston SC USA
Thanks for the prompt reply. I find it interesting that the overall ampacity will not increase when two like cables are placed in parallel.

Thanks again..

#130745 - 12/01/06 01:34 PM Re: Max current load
iwire Offline

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
That is not always the case.

2 cables with 1/0 or larger conductors will have double the ampacity. 3 cables with 1/0 or larger will have triple the ampacity.

In general there is little benefit from paralleling conductors smaller than 1/0 and you can only do it for specific installations.
Bob Badger
Construction & Maintenance Electrician


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