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SubGrade 84
Double Breaker

Is there a limit to the number of double breakers installed in a CB panel (besides rated/maximum amp draw). I am in the process of finishing my basement and am at the wiring phase. I have a 100amp Cutler Hammer panel with 22 poles and 22 spaces (I need to be able to run a total of 29 circuits). Does a double breaker count as two circuits even though it uses a single pole? My aletrnative is to upgrade the panel to a 100amp 30 pole 30 space. I want to get this right before the inspector is scheduled. Any help will be appreciated.

Thanks.

JLMCDANIEL
Re: Double Breaker

No, you can use as many double breakers as you have the space. The total of the amperage marked on the breakers is of no significance. The individual breakers protect the individual circuits, the main prevents overloading the panel and the service. In other words you could put 300 amps total breakers in a 100 amp panel and it would be OK as long as the total draw at one time does not exceed 100 amps.
Jack

Fencepost
Re: Double Breaker

Some panels DO have restrictions on just where in the panel the double breakers can be placed. Look at the panel manufacturer's label, this will tell you what "type" of breakers can be placed in each space.

The "type" is usually a one or two letter code, and it should also be labeled on the breaker.

In some cases, you can physically install breakers of a different type than is specified, but you would be stepping outside the ratings of the UL listing and your electrical inspector may not appreciate that.

heinselectric
Re: Double Breaker

I agree with the other answers. Something to keep in mind though: The price of some "piggy-back" or "tandem" breakers has gone through the roof (ahem...Square D QO). If the panel is in an accessible location and you're a pretty handy amateur electrician, It may actually be cheaper to put in a small 60 amp subpanel. I've actually crunched the numbers on a few jobs and it was cheaper to go with a subpanel. I would only suggest it if you're really sure of what you're doing though.

Fencepost
Re: Double Breaker

Just because it's a "200A" panel doesn't mean that you have to limit the total amperage of the branch circuits to less than 200A. For example, if there was enough space and you had the need, it's just fine to install 15 double-pole circuit breakers rated at 20A each -- a total of 300A. Of course, you want to make sure that the normal total load of the panel is less than the rating of the panel or you'll constantly be tripping the main breaker.

P.S. -- Sorry, JLMcDaniel, I guess I just reiterated what you said.

NewHusband
Re: Double Breaker

Remember to label your box. My old box is labeled in such a way I cannot make out what is what. That is going to be my next major project once the kitchen remodel is done.

sparky rw
Re: Double Breaker

this can be a real can of worms. two wire(with ground) circuits are fine. three wire(w/ground) are a whole lot differant. This is a neutral problem. You dont want both legs of a three wire homerun on the same twin breaker. the temptation to use three wire romex is great(2 circuits in one piece of romex) but with twin breakers you can have problems (expensive ones). there is more to it than this but if you are using twin breakers w/3 wire romex you should consult a licensed electrician

Fencepost
Re: Double Breaker
sparky rw wrote:

this can be a real can of worms. two wire(with ground) circuits are fine. three wire(w/ground) are a whole lot differant. This is a neutral problem. You dont want both legs of a three wire homerun on the same twin breaker. the temptation to use three wire romex is great(2 circuits in one piece of romex) but with twin breakers you can have problems (expensive ones). there is more to it than this but if you are using twin breakers w/3 wire romex you should consult a licensed electrician

What Sparky is trying to say is that if you have two 120V circuits in a single 12/3+G cable, the two circuits need to be on separate poles otherwise you'll overload the neutral. If you put both circuits on the same twin breaker, that will be the case. To avoid this, the two circuits must be on breakers that are connected to separate busbars in the panel.

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