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-   -   NEC compliant 120V subpanel connection? (https://www.askmehelpdesk.com/showthread.php?t=347413)

  • Apr 28, 2009, 08:28 PM
    326gab
    NEC compliant 120V subpanel connection?
    How many wires are needed for a 120V subpanel. I thought three is fine.. (Hot, Neutral, Ground) just the same as 4(Leg A, Leg B, Neutal, Ground) is fine with a 240V subpanel. 120V subpanels are very uncommon.. but I don't want or need 220v in this case. A Colorado inspector just dinged me for a code violation on the panel. I'm not super strong on NEC.. but the foregoing sounded reasonable to me.
  • Apr 28, 2009, 08:46 PM
    Missouri Bound
    I see no reason why you can't have a 120 sub panel. I think the inspector didn't use any reasoning. Check out the code yourself, log on to the NFPA website and follow instructions. You will have to register.
  • Apr 29, 2009, 02:48 AM
    tkrussell
    I believe the issue is the panel you have is rated 120/240 volts. I have not seen a 120 volt only rated panel. What is the make and model number of your panel?
  • Apr 29, 2009, 12:05 PM
    326gab
    the panel is SqureD homeline.. model HOM2-4L70RB labeling shows
    120 Vac 1 ph. 2W (I'm assuming 2Wire... means 2Wire+Ground)
    120/240 Vac 1 ph 3W (here I'm assuming that 3W really meand 3wire + ground)

    I chose the 2W option to install the feeder... 3 wires.. Black / White / Red where Black= hot; White= Neutral; and Red tied to ground... however in this box I believe the ground bar is still bonded to the case of the panel. I didn't wrap any identifying tape (white or Green) on the red lead used as Ground. The box is installed exterior on a post under my deck to provid for some UG lighting and a convenience outlet... GFI is on the outlet(s).
  • Apr 29, 2009, 12:19 PM
    Stratmando

    I would run 240 volts to panel(4 wires)
    And just use 120 volt breakers, The balancing doesn't hurt.
    Not necessarily your case, but many 120 volt panels installed seem to be upgraded eventually.
  • Apr 29, 2009, 12:45 PM
    326gab
    In retrospect, I agree... would have been less of a hassle.. but already installed and working... I had the extra cable to do it but it was only 12-3 not 12-3 W/G. I am going through home sale process and I think the inspector is just confused by the 120V config of the subpanel because I'm guessing his training has taught him that all subpanels should have 4 wires and didn't bother to make a distinction between how a 120v panel could be wired vs. a 220V panel. This one won't get upgraded... it only has 2 standard 120V circuit breaker slots.
  • Apr 29, 2009, 01:58 PM
    tkrussell
    May be a situation where the inspector either did not realize the straight 120 volt rating of the panel, or does not recognize the rating.

    I did find on page 42 :
    http://static.schneider-electric.us/...1100CT0501.pdf


    They have both ratings, 120 2 wire and 120/240 3 w.

    Have you submitted the specs to the inspector?
  • Apr 29, 2009, 02:47 PM
    326gab
    Thanks for the additional info... I haven't submitted specs to the inspector; but believe there is enough info here to clear up the situation. I suppose I could just remove the dumb thing, create 2 circuits with a common ground and call it quits. But what I have is at least more flexible (could have a total of 4 circuits with 1/2 height breakers, I have 3 in there now... but could get away with 2) and still has the right protection needed for the situation. So, I'll stand my ground for now.

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