Ask Me Help Desk

Ask Me Help Desk (https://www.askmehelpdesk.com/forum.php)
-   Electrical & Lighting (https://www.askmehelpdesk.com/forumdisplay.php?f=105)
-   -   Sub panels (https://www.askmehelpdesk.com/showthread.php?t=185656)

  • Feb 18, 2008, 09:47 PM
    cdw
    Sub panels
    When installing a sub panel in a single family dwelling coming off a main panel do you size your wire as a feeder according to 310.15 (b) (6) or do you size it as a branch circuit?
  • Feb 18, 2008, 10:04 PM
    stanfortyman
    Depends on location.
    In my area we are allowed to use 310.15(B)(6) for 100A sub-panels. Meaning #2al or #4cu.
    I use #2SER ALL the time for 100A sub-panels.

    And NO, I don't want to get into the argument about whether this is allowed. Our AHJs allow it and that's all I've ever known around here.

    IMO it is common sense. In a residence a 100A sub-panel will have JUST as much load diversity as a main 100A panel, so why should a sub-panel be required to be fed with larger wire?

    Anyway, check with your local AHJ and see what he says.
    Worst case scenario, use a 90A breaker.
  • Feb 19, 2008, 06:47 AM
    tkrussell
    As Stran states, there should be no reason not to use table 310.15 (B) (6), as this tables is for residential services and feeders, and a cable to a subpanel is considered as a feeder.

  • All times are GMT -7. The time now is 12:12 PM.