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Thread: Amp Rating

  1. #1
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    Default Amp Rating

    This is a service panel in a 1968 home. I have a few questions for the sparky's. 1) What is the reasoning for designing the panel this way? 2) What is the Amperage rating? 3) Do the four breakers need to all be tied together, tied together like a quad breaker with two inside tied together and two outside tied together or 1&2, 3&4 tied together?? I understand that the two outside breakers will need to be replaced. Thanks for any advice.

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  2. #2
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    Default Re: Amp Rating

    Quote Originally Posted by Tom Rees View Post
    This is a service panel in a 1968 home. I have a few questions for the sparky's. 1) What is the reasoning for designing the panel this way? 2) What is the Amperage rating? 3) Do the four breakers need to all be tied together or tied together like a quad breaker with two inside tied together and two outside tied together? I understand that the two outside breakers will need to be replaced. Thanks for any advice.
    Not having seen one of those before, and not having the wiring schematic from the label (I could not find a wiring schematic on the internet) ...

    1) What is the reasoning for designing the panel this way?
    - Appears to be a split bus panel (I have not seen a split bus panel like that one before, possibly Jim Port or one of the electricians has)
    - Usually, the reason for a split bus panel is cost (cheaper as no main is required, but that has mains)

    2) What is the Amperage rating?
    - There are two 60 amp breakers for the two mains - one for the upper section bus and one for the lower section bus
    - BOTH the top and bottom mains have the handles broken off
    - the top two main breakers should be tied together for the upper section bus
    - the bottom two main breaker should be tied together for the lower section bus
    - those four breakers need to be replaced, preferably with two internal trip double pole breakers (no handle ties needed)
    - the mains (buses) are rated for 200 amp per the label, but you can't really just add the two 60 amp mains together and get 120 amp, you would need to do a load calculation to see what the service size is, so ... just note that there are two 60 amp mains which need to be replaced

    3) Do the four breakers need to all be tied together or tied together like a quad breaker with two inside tied together and two outside tied together?
    - see answers in 2) above

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

  3. #3
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    Default Re: Amp Rating

    Thanks Jerry, I see a lot of panels but have never seen one quite like this, had me scratching my head.

    Tom Rees / A Closer Look Home Inspection / Salt Lake City, Utah
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  4. #4
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    Default Re: Amp Rating

    Just a WAG but that may be intended for duplex type setup when one service provides power to two different areas. Definitely broken and I agree the two top breakers appear to need to be a common trip and the bottom two on a common trip with the possibility of all four being tied together. Very unusual setup, new to me also.

    Jim Luttrall
    www.MrInspector.net
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  5. #5
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    Default Re: Amp Rating

    Quote Originally Posted by Jim Luttrall View Post
    Just a WAG but that may be intended for duplex type setup when one service provides power to two different areas. Definitely broken and I agree the two top breakers appear to need to be a common trip and the bottom two on a common trip with the possibility of all four being tied together. Very unusual setup, new to me also.
    That's what I thought too Jim, but this property has always been a single family home in high end area. Circuits do not seem to be split between different areas. Learn something new every week. That's one of the things I like about this job.

    Tom Rees / A Closer Look Home Inspection / Salt Lake City, Utah
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  6. #6
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    Default Re: Amp Rating

    Never seen anything like that one. The wiring diagram on the label would be the real key.

    All answers based on unamended National Electrical codes.

  7. #7
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    Default Re: Amp Rating

    Quote Originally Posted by Jim Port View Post
    Never seen anything like that one. The wiring diagram on the label would be the real key.
    Hi Jim, I went back and checked and found this picture. It's out of focus because I was actually getting a picture of the unmarked white conductor. Maybe you can read it.

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  8. #8
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    Default Re: Amp Rating

    I can deal with the out of focus aspect, however ... ... the part I need to see is the part behind that white conductor.

    The other diagrams/schematics to the right may give a clue in conjunction with the schematic behind the white conductor we cannot see.

    I am sure sure it is some type of split bus panel, but why it is that way is the question.

    The service entrance conductors terminate into the terminal block on the left, from there there are manufacturer installed conductors which go to the 4 breakers.

    There are two options:
    1) and the most likely option - there are supposed to be two separate mains, the top pair and the bottom pair (of the four mains)
    2) and the least likely option - they were all connected together as one main for the entire panel (but that doesn't make sense ... of course, neither does that configuration even with two separate mains)

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
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  9. #9
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    Default Re: Amp Rating

    On the original photo you posted I could clearly see 200A under mains.


  10. #10
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    Default Re: Amp Rating

    Quote Originally Posted by Jerry Peck View Post
    ...
    - the mains (buses) are rated for 200 amp per the label, but you can't really just add the two 60 amp mains together and get 120 amp, you would need to do a load calculation to see what the service size is, so ... just note that there are two 60 amp mains which need to be replaced ...
    Quote Originally Posted by Mark Reinmiller View Post
    On the original photo you posted I could clearly see 200A under mains.
    That is on the label and is the maximum rating of the mains and buses, but not the rating of the service ... unless you see 200 amp on those breakers someplace I don't ...

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
    www.AskCodeMan.com

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