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    Prsmn2's Avatar
    Prsmn2 Posts: 4, Reputation: 1
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    #1

    Oct 9, 2011, 11:49 AM
    Main breaker question
    My main box has 4 200 amp breakers connected together by a bar. I am wondering why there are 4, as opposed to just 2, or one ? I have a few 240v circuits, is this the reason ? Just curious...
    donf's Avatar
    donf Posts: 5,679, Reputation: 582
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    #2

    Oct 9, 2011, 12:47 PM
    Is this a residence? What is the size of the incoming service from the PoCo?

    Can you take a picture of this configurations and attach it to this item via the "Advanced Features"
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    Prsmn2 Posts: 4, Reputation: 1
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    #3

    Oct 9, 2011, 01:22 PM
    It is a residence. I have no way to attach a pic, but the breaker(s) are stacked on their side, with a bar connecting all the switches.
    stanfortyman's Avatar
    stanfortyman Posts: 5,598, Reputation: 279
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    #4

    Oct 9, 2011, 01:46 PM
    That is a 200A main breaker.
    What it actually is is two 100A breakers, in parallel, tied together, creating a 200A, 240v breaker.
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    stanfortyman Posts: 5,598, Reputation: 279
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    #5

    Oct 9, 2011, 01:49 PM
    Looks like this, right?
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    #6

    Oct 9, 2011, 05:01 PM
    Yep, it looks like that STAN... so it is a double pole 220 breaker ? I should just pull the cover off the box to see how its wired... thanks guys for the info... I appreciate it..
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    stanfortyman Posts: 5,598, Reputation: 279
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    #7

    Oct 9, 2011, 05:09 PM
    No, it is a double-pole 200A breaker.

    You can pull the cover off, but I am not sure what it is you are looking for. If it has been working I would assume it is wired right. In fact, I can't see how it could be wired wrong in the first place.
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    #8

    Oct 9, 2011, 05:32 PM
    I guess what I am looking for is an explanation as to how it works... maybe this is a theory question... there are 2 busses in the box, so 2 of the mains are connected to each buss ?
    donf's Avatar
    donf Posts: 5,679, Reputation: 582
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    #9

    Oct 9, 2011, 05:55 PM
    Yes, there are two main buses. However they are out of "Phase" with each other.

    That's how the 240V are created. Each phase is 120 V.

    Their "Peak to Peak" voltage is 240V.
    stanfortyman's Avatar
    stanfortyman Posts: 5,598, Reputation: 279
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    #10

    Oct 9, 2011, 06:01 PM
    In most aspects of electrical work, we do not use the sum of amperages. Meaning it is useless to add up the breakers in your panel. The results mean nothing.

    In this case though, since there are two 100A breakers wired in parallel, the amperages are added together to create a 200A breaker.

    It's a similar principle as paralleling conductors. Two conductors in parallel have twice the amperage as one conductor.
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