# 2 hots, 1 neutral, into a tandem breaker?



## k2x (May 20, 2008)

That's not right is it? I saw one yesterday but I just left it alone. I'm thinking it should be a hot off of each leg??

Is a shared neutral circuit what is called a mwbc??

Thanks!!


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## 480sparky (Sep 20, 2007)

99% of the time, tandem breakers have two circuits on the same phase, or leg.

So if you have two circuits sharing a white, it's a violation, as it is not a MWBC.

There are some tandems that can, but they're not that common. To find out, take a volt reading between the two circuits. If you have 240V, you can share the neutral.


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## k2x (May 20, 2008)

480sparky said:


> 99% of the time, tandem breakers have two circuits on the same phase, or leg.
> 
> So if you have two circuits sharing a white, it's a violation, as it is not a MWBC.
> 
> There are some tandems that can, but they're not that common. To find out, take a volt reading between the two circuits. If you have 240V, you can share the neutral.


Thanks, there is no voltage between the circuits... So if a guy wanted to fix this and above there is double pole 240's etc, (no room), and below there is another tandem, (same amps,15), but not using a shared neutral, and below that is spare space with a regular 15, unused. I'm thinking I could swap one of these wires in question with one of the wires on the tandem below. But, I thought I had read that the handles had to be together and tied?? 

Thanks again for the info..


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## 480sparky (Sep 20, 2007)

The handles only need to be tied together if one of two things happen:

Both circuits go to the same peice of equipment (say, a 240v air conditioner). But in your case, it won't work because it's not hooked up to 240 volts.

Both circuits are terminated onto a device with one strap, or yoke.

See 210.4.

To correct this situation, you need to seperate the two circuits so there is 240v between them, being careful that you don't have both circuits going to one device somewhere.


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## KayJay (Jan 20, 2008)

Just to note, if you’re on the ’08 NEC, handle ties are now required for MWBC’s. 210.4*. It is not for the purpose of a common trip, but for simultaneous disconnecting for the ungrounded conductors for worker safety and to prevent an unintentional open neutral condition during service or repair work. **

Just throwing it out there!!*


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## waco (Dec 10, 2007)

Is it a tandem or a two pole breaker? If it is a piggy back or tandem, then it sounds like one connection has two blacks on it and one connection has a white on it which doesn't make any sense, to me.

Is it possible it is an AFCI with two blacks connected? Does it have a yellow button on it?


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## TOOL_5150 (Aug 27, 2007)

The only tandem breakers that can provide 240V are zinsco and GE, both of which I would never use. FPE breakers can as well but I have never really spent much time looking at them, as much as I have ripping them out.

~Matt


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## k2x (May 20, 2008)

waco said:


> Is it a tandem or a two pole breaker? If it is a piggy back or tandem, then it sounds like one connection has two blacks on it and one connection has a white on it which doesn't make any sense, to me.
> 
> Is it possible it is an AFCI with two blacks connected? Does it have a yellow button on it?


Oh sorry, black and red into the tandem and white to the neutral bar from a 14-3 w/ground. No afci's. I went back today and it had been done correctly, (black into one tandem and red into the tandem below, 240 volts), I just didn't look close enough. But,, I learned a few things so thanks..


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