# 20 amp breaker on 10/3 wire



## BigJimmy (Jun 30, 2006)

Yes, it is fine to use #10 wire with a 20A OCP device. BTW, there are times when this is done, i.e. using a gauge of wire whose ampacity is greater than the breaker rating, to avoid voltage drop in long circuit runs.


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## HouseHelper (Mar 20, 2007)

And did you really need the 10/3? Most AC/heating units are 240V, so 10/2 (or 12/2) was all you needed.


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## Duane 70 (Sep 16, 2008)

Well, now that you mention it, I guess not. I suppose I was thinking two hots and a neutral. Amateur hour:bangin:!! Oh well, too late now. I guess this way, I am ready for anything that comes along!!


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## theatretch85 (May 17, 2008)

You could always make that a multi-wire branch circuit and put in two separate outlets with a double pole 20amp breaker. You already have the neutral and your two hots there so there would be no issue with that. Otherwise if you really don't need or want the second outlet, I would just cap off the Red wire on both ends and just use the black, white, and ground for the one outlet.


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## Duane 70 (Sep 16, 2008)

Since it's a 240v a/c-heat unit, shouldn't I cap off the white (it's landed on the neutral bar in the breaker panel) and use the red and black (landed on the breaker) and ground wires? I have run new circuts (two 20 amp for outlets and bath outlets and two 15 amp for lights and bath light/fan) already so I have plenty of circuts. I just didn't give any thought to only needing 10/2 for the a/c unit. Thanks for everyone's feedback on this. Let's me know to think things through better next time.


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## theatretch85 (May 17, 2008)

Duane 70 said:


> Since it's a 240v a/c-heat unit, shouldn't I cap off the white (it's landed on the neutral bar in the breaker panel) and use the red and black (landed on the breaker) and ground wires? I have run new circuts (two 20 amp for outlets and bath outlets and two 15 amp for lights and bath light/fan) already so I have plenty of circuts. I just didn't give any thought to only needing 10/2 for the a/c unit. Thanks for everyone's feedback on this. Let's me know to think things through better next time.


There I go "assuming" again! I "assumed" that with it being only 20 amps that it was likely a 120 volt load and not 240 volt. Yes in the case of a 240 volt load you would use the black, red, bare copper ground and cap off the white on both ends. Sorry for any confusion on that.


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