How to power 125A sub-panel?

[nwav8tor]

Newbie's ignorance showing

Am I correct to assume that a main lug panel rated 125A can be powered by using a maximum of two 60A circuit breakers in the main panel?

Thanls,
Paul

 

[DekeT]

If you are asking if you can use a 60 amp DOUBLE POLE breaker to power a 125 amp capacity panel, then yes. You are going to get max 60 amp out there. You can power the subpanel with a 20 amp dp breaker(though I do not recommend that, just theory), just don't use a larger than 125 amp breaker to power it.

You need to buy some books and study up some more before you attempt this. Look at the pics. Not saying you can't do this with some help but at this point I am worried for you.

 

[WhoWhatNow]

Sounds like the OP wants to use 2 two pole breakers to power the panel. Two black hots and two red hots to the subpanel. I can't imagine that would be code if that is the case. Why not just use one double pole 125amp?

 

[Charles (in GA)]

You DO NOT add the amperage of two breakers together to get the amperage. Common mis-conception. To power this panel, you will have a double pole breaker. It is, in essence, two breakers riveted together and the handles are connected together. If you use one that the two handles are each marked 60amp, then you have a 60 amp double pole breaker, if you use one marked 90 amp, then you have a 90 amp double pole breaker, and so forth. Above 60 amp the breakers get real expensive, real quick.

Charles

 

[pattenp]

You use one breaker like this up to 125A in the main-panel to feed the 125A sub-panel.

 

[Highbeam]

I just installed and passed inspection on my garage subpanel. I bought a 100 amp panel for the garage and fed it with a 60 amp breaker from the house main panel as pattenp pictured above. Used 6 gauge copper wire to match the 60 amp breaker. The 100 amp breaker at the garage subpanel is used as a big on/off switch.

 

[pattenp]

"big on/off switch" is aka "main disconnect"

 

[nwav8tor]

Thanks guys, all your responses set me straight. My original assumption was flawed!
I can use any size double pole breaker 125A or less in the main panel to power the 125A sub-panel (using appropriately sized wire of course), correct?

Is this a way to view it: the 125A rating on the panel is for EACH bus bar on the panel, not a total rating for the whole panel?

Two other associated questions...My house's main breaker panel has four CBs at the upper end that are tied together with a single bar that has "200" on it. 1) Does that mean I have 200A service? 2) What amperage is each of those 4 individual CBs?

Thanks again,

Paul

 

[oleguy]

yes.you have a 200 amp service.each pair is 200 amp.each hot buss is 200 amp.but not 400 amp total.

 

[Charles (in GA)]

Two other associated questions...My house's main breaker panel has four CBs at the upper end that are tied together with a single bar that has "200" on it. 1) Does that mean I have 200A service? 2) What amperage is each of those 4 individual CBs?

Some panel manufacturers, GE that I know of, use smaller breakers, sandwiched together to make a larger breaker. They run them in parallel. If you are seeing four breakers all riveted/ganged together, you are seeing four 100 amp breakers, two for one hot feed and two for the other. I'm not so sure I like this setup, but it seems to work.

Other panels, Square D and Siemens for instance, use a single huge breaker that carries the two independent hot circuits thru the single housing of the breaker, with one handle sticking out.

Charles

 

[nwav8tor]

Some panel manufacturers, GE that I know of, use smaller breakers, sandwiched together to make a larger breaker. They run them in parallel. If you are seeing four breakers all riveted/ganged together, you are seeing four 100 amp breakers, two for one hot feed and two for the other. I'm not so sure I like this setup, but it seems to work.

Other panels, Square D and Siemens for instance, use a single huge breaker that carries the two independent hot circuits thru the single housing of the breaker, with one handle sticking out.

Charles

My panel is a Siemens, but still has the 4 MAIN breakers connected by the single gang bar. Guess they use both methods...

Paul

 

[PRH44]

The manufactures of such breakers have acquired a UL listing for this configuration as an assembly. Individual Breakers are not permitted to be paralleled, as this would not be a UL listed assembly.
The smallest conductor permitted to be paralleled is a 1/0

 

[Norcal]

My panel is a Siemens, but still has the 4 MAIN breakers connected by the single gang bar. Guess they use both methods...

Paul

It's not four main breakers, it's just 4-poles wide, BTW, ITE (now Siemens) was the 1st company to produce a main breaker made in that manner in the 1970's, Goverment Electric, GE, & Cutler-Hammer also offered it.

 

[nwav8tor]

It's not four main breakers, it's just 4-poles wide, BTW, ITE (now Siemens) was the 1st company to produce a main breaker made in that manner in the 1970's, Goverment Electric, GE, & Cutler-Hammer also offered it.

Oops, my ignorance of proper terminology is showing again!! I sure am learning alot here...

Paul