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-   -   How long can I run 4/0 200 amp circuit (https://www.askmehelpdesk.com/showthread.php?t=553506)

  • Feb 11, 2011, 06:39 AM
    felicesnow
    How long can I run 4/0 200 amp circuit
    Power company said I could run 4/0 wire 225 feet from my meter/main breaker panel to a sub-panel in my new home. Electricans that I work with said it would be too much voltage drop. What should I do?
  • Feb 11, 2011, 07:46 AM
    jcaron2
    I was under the impression that 5% voltage drop was at the upper end of the acceptable limit. With 4/0 aluminum wire, at a full load 0f 200A, I think you're only going to drop around 3.7%, so I would agree with the power company.

    That being said, please bear in mind that I'm not an expert. Hopefully tkrussell will chime in. He's the real expert with this stuff.
  • Feb 11, 2011, 07:56 AM
    felicesnow
    Comment on jcaron2's post
    Thank you. Im like you ykrussell seems to know his stuff.
  • Feb 11, 2011, 10:27 AM
    tkrussell
    The max recommeded voltage drop for both feeder and branch circuit is 5%.

    Typically, 3% is applied to the feeder, and 2 % to the branch circuit.

    So, this feeder should be sized to keep the Vd to 3% or less.

    The important variable is the load amperage. A 200 Amp service should not be loaded more that 80%, or 160 Amps.

    If the load is to be assumed to be 160 amps, then #250 MCM aluminum is required.

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