OT: tap dancing on electrical land mine.....

Dennis Minn · Sep 10, 2019

All,

I refrained from abswering a question about residential wiring in US (current NEC compliance). I would ask, does a two pole 20 amp wired for a single 120v receptacle would still protect the same as a single pole breaker.

This assumes one hot, one neutral, one equipment grounding conductor, properly landed at both ends at a typical home receptacle.

I read the other recent electrical question and I think that there was a bit of misguidance. 20 amps is 20 amps. Even though wiring a two pole breaker for a single pole would be a waste, however, it is still electrically viable and compliant. One hot at the breaker, one neutral on the bar, and a qualified EGC, continuous metallic conduit or wiring to the non-subpanel ground/neutral bus bar.

Have at it....

D>

Steve@Advance · Sep 10, 2019

If I understand properly, you are asking if only one side of a 2 pole 20a breaker is used for a 15/20 amp duplex receptacle, wired with #12 wire is safe.

I would say yes, it will give adequate protection.

That is provided the other side is either left vacant, or used for another circuit of equal wire size.

Is it legal, no.

M-MAN · Sep 10, 2019

Sounds logical BUT you can't have 20 amps on a single receptacle unless it's a 20 amp receptacle. Lots of double pole breakers have a metal coupler on top you can remove to make it a single pole.

Switchflicker · Sep 10, 2019

Another interesting tidbit is that if you run two circuits (15 or 20 amp, doesn't matter) to one duplex plug, (and that can be done by breaking the little tabs that join the two screws on each side of the duplex plug) then the circuit breakers that supply the current must be joined together with a coupler of some sort. Or so says my electrical guy. That's so that when you throw the breaker for the plug(s) you turn off both circuits at the same time. No surprises for the electrician!
The usefulness of doing the two circuit thing would be in a place like a kitchen where you need lots of circuits for toasters and coffee pots and the like.

Dennis Minn · Sep 10, 2019

Steve,

You have succinctly summed up what I intended. I do, however, disagree as far as being legal. Using one pole of a two pole 240v residential breaker is allowable under current NEC. I agree that one pole should remain unused, or wired completely to a separate outlet, rated for 20amp protection.

D,

randyrenfro7 · Sep 11, 2019

No GOOD electrician gets surprised, he checks with meter before touching.

dr sportster · Sep 11, 2019

Please cite the code article ?

Janicholson · Sep 11, 2019

Interesting issue. My comment will be short (pun intended). If a 220 breaker remains connected at the toggles, and wired to two different 120 v circuits, when one circuit is tripped, the second is also tripped, possibly causing a critical tool to stop working at just the wrong moment. Jim

OT: tap dancing on electrical land mine.....

Dennis Minn

Member

Steve@Advance

Well-known Member

M-MAN

Well-known Member

Switchflicker

Member

Dennis Minn

Member

randyrenfro7

Member

dr sportster

Well-known Member

Janicholson

Well-known Member

Similar threads