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Thread: 200 amp ats between 100 amp meter and panel?

  1. #1
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    200 amp ats between 100 amp meter and panel?

    Here's the scenario, 100 amp pull out fused meter feeds a 200 amp auto transfer switch which feeds a 100 amp breakered Panel. Obviously a 200 amp ATS feeding a 100 amp panel is a clear code violation BUT, because the 200 ATS is fed by a 100 amp meter with fused disconnecting means, does the eliminate the need for a 200 amp ATS breaker altogether, thus allowing the 200 amp ATS to act almost as a non fused disconnect?
    I'm sure this is an easy one for the Mike Holts army of electrical Genius

  2. #2
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    I'm not completely following the setup, but I don't think you have a code violation.

    A 200A ATS can be used in a 100 amp feeder or a 100 amp service. It not a problem if the ATS is oversized.

    But the ATS also has a 200A breaker? On the line side, generator side, or output side?

    And what size is the generator and that feeder? If the generator and its feeder are also sized at 100 amps, it all sounds OK to me.

  3. #3
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    Other than being a waste of money (unless there is some future consideration or you happened to already own it), there is nothing wrong with having a switching device rated for more than the circuit ampacity. An ATS is not a load or protective device (usually), it's simply a switch.
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  4. #4
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    The reason for the 200 rather than a 100 is because the generator package that the owner purchased came with a 200 amp ATS. The generator itself has its own 80 amp breaker right on the generator(which BTW is 17k) The 200 amp ATS breaker only kills the utility side of the ATS (just to be clear, ATS breaker goes off, Generator sees loss of utility power and starts up, then switches ATS to Gen power)

  5. #5
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    It sounds fine to me.

  6. #6
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    Quote Originally Posted by Jraef View Post
    Other than being a waste of money (unless there is some future consideration or you happened to already own it), there is nothing wrong with having a switching device rated for more than the circuit ampacity. An ATS is not a load or protective device (usually), it's simply a switch.
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

  7. #7
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    Quote Originally Posted by Jraef View Post
    Other than being a waste of money (unless there is some future consideration or you happened to already own it), there is nothing wrong with having a switching device rated for more than the circuit ampacity. An ATS is not a load or protective device (usually), it's simply a switch.
    Agreed. Indeed, that's why it's included with the generator. They just buy and supply one size for all of them.

    Same reason our utility uses 200A meters on 100A services.

  8. #8
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    Agreed with the previous posts as long as everything is protected at its rating somewhere upstream.

    Since the 100 amp pull out fused meter protects the 200A normal side of the ATS and the 100 amp breakered Panel when in the normal position AND the 80A breaker in the generator protects the 200A emergency side of the ATS and the 100 amp breakered Panel when in the emergency position, you are ok.
    Ron

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