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Thread: OCPD at MDP

  1. #1
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    OCPD at MDP

    So i have a 600amp/480v MDP i told my boss that he needs to put a OCPD (currently it only has main lugs) in the panel as 408.36 now he said that it doesnt need one because the main service disconnect by the service transformer serves as a disconnecting means. the service transformer with the main service disconnect will be about 400 ft away from our power rack with the MDP. is there exception to this rule,, is he right?

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    Quote Originally Posted by jctj88 View Post
    So i have a 600amp/480v MDP i told my boss that he needs to put a OCPD (currently it only has main lugs) in the panel as 408.36 now he said that it doesnt need one because the main service disconnect by the service transformer serves as a disconnecting means. the service transformer with the main service disconnect will be about 400 ft away from our power rack with the MDP. is there exception to this rule,, is he right?
    If the main service disconnect has a breaker or fuses that are no more than 600A and the conductors are rated for that OCPD, then yes, he is correct. You only need it in one place. Now from a convenience standpoint, it's often desirable to have a Main breaker in a switchboard or panelboard, but it's not required. Because right now if you have an issue in that panel and need to kill power, you have to (1) KNOW where that disconnect is, and (2) trek 400' to get to it.
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    10-4. so i guess im misinterpreting 408.36.
    and where would I find it in my code the answer you gave me so I can highlight it for future reference.

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    Quote Originally Posted by jctj88 View Post
    10-4. so i guess im misinterpreting 408.36.
    and where would I find it in my code the answer you gave me so I can highlight it for future reference.
    The last sentence of 408.36, located at any point on the supply side of the panelboard. I believe that includes the panel 400' away.

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    right on I see that so that's what I was wondering if it did have a distance rule or not.. thanks.

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