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#89574 - 10/09/04 03:13 AM Multiwire Branch Circuit with Unequal OCP
iwire Offline
Moderator

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
I am currently remodeling office space, I have an existing 8/3 AC cable that runs from a panel 125' to a kitchenette.

I plan to use this 8/3 AC as a multiwire branch circuit to feed a 120 volt 3000 watt water heater, the other side of this circuit will feed a 20 amp receptacle for a refrigerator.

This will mean I will have a single pole 35 and a single pole 20 feeding this multiwire branch circuit.

I see no problem with this, however my coworkers think I am nuts, and who would know that better then them.

Am I missing something, is this a NEC violation?

Any responses are appreciated.

Thanks, Bob
_________________________
Bob Badger
Construction & Maintenance Electrician
Massachusetts

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2014 / 2011 NEC & Related Books and Study Guides
#89575 - 10/09/04 05:34 AM Re: Multiwire Branch Circuit with Unequal OCP
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
Bob I think you comply with 210.4(C) and I assume that the common conductor of the circuit is insulated and that there is also an equipment grounding conductor. Where do I put the green sticker?
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George Little

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#89576 - 10/09/04 09:52 AM Re: Multiwire Branch Circuit with Unequal OCP
electricman2 Offline
Member

Registered: 11/09/03
Posts: 234
Loc: Thomasville, NC USA
Go for it. Nothing says that the OCPD's have to be equal.
_________________________
John

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#89577 - 10/09/04 08:15 PM Re: Multiwire Branch Circuit with Unequal OCP
winnie Offline
Member

Registered: 09/15/03
Posts: 652
Loc: boston, ma
I know that this is picking nits, but if you use a #8 Cu for a 20A circuit, wouldn't you also be required to use #8 for the EGC? *grin* Of course, given your normal work situation, I'm guessing that this circuit is in pipe.

-Jon

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#89578 - 10/10/04 04:02 AM Re: Multiwire Branch Circuit with Unequal OCP
iwire Offline
Moderator

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
George, yes I have a white insulated grounded conductor.

electricman2 That is my thinking too.

Jon, I do not think you are nit picking, you are right on the money IMO.

If this was 8/3 MC cable the EGC would be 10 AWG which as you point out would be to small for the 20 amp circuit per 250.122(B)

This happens to be 8/3 AC cable, type AC cable does not have a copper EGC at all, it utilizes the armor as the EGC.

Thanks for the replies

Bob
_________________________
Bob Badger
Construction & Maintenance Electrician
Massachusetts

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