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  1. #1
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    Default Main Panel For Two Buildings

    The property in question has overhead electric service to the meter mounted on a pole. Below the meter is a panel that I will call the "main panel". This "main panel" does not have a main disconnect or a main breaker but it has two breakers that service two buildings that each have their own "sub panel" (or whatever Jerry calls them ).

    1) Does this "main panel" need a main disconnect or a main breaker?

    2) At the "main panel" the breaker for Building A is rated at 125 amps. In Building A the "sub panel" has a main breaker rated at 150 amps. Does this "sub panel" need a main breaker and, if so, is there a problem with it having a higher rating than the breaker at the "main panel"?

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  2. #2
    Fred Warner's Avatar
    Fred Warner Guest

    Default Re: Main Panel For Two Buildings

    See Articles 230 and 250 in NEC


  3. #3
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    Default Re: Main Panel For Two Buildings

    1) Does this "main panel" need a main disconnect or a main breaker?

    No - six or less switches as per NEC article 230.71

    2) At the "main panel" the breaker for Building A is rated at 125 amps. In Building A the "sub panel" has a main breaker rated at 150 amps. Does this "sub panel" need a main breaker and, if so, is there a problem with it having a higher rating than the breaker at the "main panel"?

    The sub-panels do not require a main breaker.
    The 150 ampere main breaker in building "A" is perfectly fine. It is looked at as a convience and not for overcurrent protection.

    Side note: The neutrals and grounds should be bonded together with the ground electrodes at the service equipment, which in this case is located on the pole at the meter. The 2 sub-panels should have the grounds and neutrals isolated from each other. The feed for those sub panels should consist of the "hot" conductors, a grounding conductor and an insulated neutral conductor.


  4. #4
    Fred Warner's Avatar
    Fred Warner Guest

    Default Re: Main Panel For Two Buildings

    The disconnects in buildings 1 & 2 must comply with 225.31, 225.32 & 225.33 if fed by outside feeder. And as noted above, where a feeder supplies a separate building or structure, the requirements of 250.32 apply. (215.6)
    A grounding electrode system must be established at each building or structure by the sounds of things.


  5. #5
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    Default Re: Main Panel For Two Buildings

    So true - One must adhere to 225.31, 225.32, and 225.33.
    The breakers at the panel cover 225.31 and 225.33

    One could make an argument that exemption 1 of 225.32 can apply.

    250.32 - yes one needs to establish a grounding electrode or grounding electrode system. The grounds and neutrals STILL remain isolated from each other at these 2 sub-panels. The grounding electrode attaches to the grounds.
    (The grounding electrode is for lightning not for fault clearing)


  6. #6
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    Default Re: Main Panel For Two Buildings

    Quote Originally Posted by Bruce Breedlove View Post
    The property in question has overhead electric service to the meter mounted on a pole. Below the meter is a panel that I will call the "main panel". This "main panel" does not have a main disconnect or a main breaker but it has two breakers that service two buildings that each have their own "sub panel" (or whatever Jerry calls them ).

    1) Does this "main panel" need a main disconnect or a main breaker?
    Bruce,

    That is the "service equipment" and those are the two "main disconnects".

    I believe you would not be confused if you would simply think in terms of "service equipment" and "other than service equipment" (i.e., "panels") and stop insisting on trying to apply your other terms, which, obviously, is not working for you and causing confusion.

    Not sure why you insist on using those terms which are then leading to your confusion.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

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