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Multiwire Branch Circuit with Unequal OCP #89574
10/09/04 06:13 AM
10/09/04 06:13 AM
I
iwire  Offline OP
Moderator
Joined: Jan 2003
Posts: 4,391
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. [Linked Image]

Am I missing something, is this a NEC violation?

Any responses are appreciated.

Thanks, Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
2017 / 2014 NEC & Related Books and Study Guides
Re: Multiwire Branch Circuit with Unequal OCP #89575
10/09/04 08:34 AM
10/09/04 08:34 AM
G
George Little  Offline
Member
Joined: Jan 2004
Posts: 1,498
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?


George Little
Re: Multiwire Branch Circuit with Unequal OCP #89576
10/09/04 12:52 PM
10/09/04 12:52 PM
E
electricman2  Offline
Member
Joined: Nov 2003
Posts: 269
Thomasville, NC USA
Go for it. Nothing says that the OCPD's have to be equal. [Linked Image]


John
Re: Multiwire Branch Circuit with Unequal OCP #89577
10/09/04 11:15 PM
10/09/04 11:15 PM
W
winnie  Offline
Member
Joined: Sep 2003
Posts: 649
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

Re: Multiwire Branch Circuit with Unequal OCP #89578
10/10/04 07:02 AM
10/10/04 07:02 AM
I
iwire  Offline OP
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
George, yes I have a white insulated grounded conductor. [Linked Image]

electricman2 That is my thinking too. [Linked Image]

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. [Linked Image]

Thanks for the replies

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts

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