two circuits, one receptacle

[apauling]

This may seem like I should know this, but i found a contractor switching half of an outlet with one circuit and supplying the other half with another 20 amp breaker. I thought that this was to be a tied breaker. No shared neutral here, just two circuits on same yoke, no control if 220 or 110/same phase, tabs broken.

This is not kitchen but living room.

Ryan, I sent you an email thanks but it kept getting sent back.

input appreciated, am on dialup, laptop, tediously slow in remotish town, so may not answer fast, have been getting disconnected

paul

 

[curt swartz]

Re: two circuits, one receptacle

What edition of the NEC covers this work?

The 99 NEC required simultaneous disconnection of the ungrounded conductors if a receptacle is supplied by more than one circuit of a multi-wire circuit. Two 2-wire circuits could be used without handle ties.

I believe the 2002 NEC requires simultaneous disconnection anytime more than one circuit supplies a receptacle. I don?t have the NEC in front of me now but one of the other members can verify what I said. If you look in the first part of Article 210 you should find the answers.

Curt

 

[hurk27]

Re: two circuits, one receptacle

Will this help?

210.7(C)
Multiple Branch Circuits. Where more than one branch circuit supplies more than one receptacle on the same yoke , a means to simultaneously disconnect the ungrounded conductors supplying those receptacles shall be provided at the panelboard where the branch circuits originated.

 

[ryan_618]

Re: two circuits, one receptacle

I think Wayne nailed this one. When I teach I get a lot of strange reactions. In a dwelling unit, a multiwire BC one strap requires handle ties, but not in commercial. In any occupancy, multiple circuits one one strap require handle ties. So, in a commercial occupancy, if you have two 120-v circuits on one strap you need handle tie if you have two nuetrals, but you don't need handle ties if you only have one nuetral!!!

 

[steve66]

Re: two circuits, one receptacle

....strange reaction.....

Ryan, I think you contridicted yourself....

In any occupancy, multiple circuits one one strap require handle ties.

But then:

So, in a commercial occupancy, if you have two 120-v circuits on one strap....you don't need handle ties if you only have one nuetral!!!

Steve

Edit: I guess this make sense if you don't consider a multiwire circuit "multiple circuits".

[ July 07, 2004, 09:24 AM: Message edited by: steve66 ]

 

[ryan_618]

Re: two circuits, one receptacle

Originally posted by steve66:

Edit: I guess this make sense if you don't consider a multiwire circuit "multiple circuits".

Thats just it! 210.4, with bold added by me.:

(A) General. Branch circuits recognized by this article shall be permitted as multiwire circuits. A multiwire branch circuit shall be permitted to be considered as multiple circuits. All conductors shall originate from the same panelboard.

So, what this is saying is that I can call a multiwire BC one circuit, or I can call it two, whatever makes my application easier.

[ July 07, 2004, 09:44 AM: Message edited by: ryan_618 ]

 

[steve66]

Re: two circuits, one receptacle

....another strange reaction......

Yes, it does seem to allow you to call it what you want. From a design standpoint, I think I would always specify handle ties for 2 circuits serving the same yoke. How often can you get added safety for the price of a handle tie??

Steve

 

[ryan_618]

Re: two circuits, one receptacle

I agree Steve. In fact, I had a strange reaction the first time I read the new section as well!!!

 

[curt swartz]

Re: two circuits, one receptacle

Wayne and Ryan, thanks for posting 210.7(C). I knew there was a change from the 99NEC but didn?t remember exactly what it was and my book wasn't handy last night. I also didn?t realize that there was still a multi-wire circuit loophole that would still permit a multi-wire circuit feeding on receptacle without the breakers being tied. I wonder why they didn?t remove ?dwelling unit? from 210.4(B) so it would cover all receptacles? Also who determines if this multi-wire circuit is one circuit or two? The inspector? The contractor? The engineer?

[ July 07, 2004, 10:00 PM: Message edited by: curt swartz ]

 

[apauling]

Re: two circuits, one receptacle

thanks guys. It's the 99 nec or cec (cal). I was sort of hoping for some oddball piece of code that I had not read or thought of. Something like 240 volts to ground, 40 amp total load on 15 amp convenience receptacle. I'm starting a new job and the paperwork, on the spot calls without time, pressure to get them all done, sometimes i get stuck with a belief that what I would never do is probably somewhere in the code, but I think that I am just going to have to go with the local flow.

thanks again guys, if they don't fire me I'll move my computer up here and get dsl, not as fast as cable but better than near snail mail.

paul