(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 15 of 15

Thread: Wiring Problem

Hybrid View

  1. #1

    Default Wiring Problem

    I just remodeled my bathroom. I am not an electrician by a long shot although I have done hundreds of receptacles and switches. When wiring gets complicated though it gives me a headache. Here is a drawing of the wiring in my bathroom. I added the light in the upper right hand corner. The rest of the wiring and fixtures already existed. Although the light in the upper left is really a fan but not that that matters. The only other thing I changed was the receptacle to a GFCI. My current problem is the light at the bottom. When I connect the red wire to the switch and turn on the switch it trips the GFCI. When I unhook the red wire then the light in the upper right works fine but that disables the light at the bottom. Everything but that one light works fine without the red wire connected. The GFCI works properly, the fan and the light in the upper right. Where the heck am I supposed to connect the red wire to so that it does not trip the GFCI and works properly?

    Thanks for help!

  2. #2
    DIY Senior Member Livin4Real's Avatar
    Join Date
    Sep 2007
    Indianapolis, IN


    Have you tried pig-tailing the load side neutral down to the bottom light to see what happens instead of using the line side neutral?

  3. #3
    Electrical Contractor/Instructor jwelectric's Avatar
    Join Date
    Jun 2007
    North Carolina


    The light on the bottom is where the problem needs addressing. Notice that the white (neutral) for this light is picked up from the line side of the GFCI but the hot is coming from the load side of the GFCI.

    Unless the lights are required to be protected by GFCI I would connect everything to the line side of the GFCI. This is the only way to have bottom light work with the neutral being tapped from the supply to the GFCI

  4. #4
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    New England


    GFCI compares the output on the load side with the return on the load side. If they aren't within very close (milliamps) of each other, it thinks some of the current is leaking (possibly through you!) and trips. As indicated, you need the lights to be wired to the same side of the gfci, either load or line depending on whether you need or want the lamps protected. Normally, the lights are separate from the gfci so if you trip it, you don't lose the lights at the same time, but this is up to you.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  5. #5
    Plumber jimbo's Avatar
    Join Date
    Aug 2004
    San Diego


    The lower light, the one fed power on the red line, has power ( hot ) from the load side of the GFCI, but the neutral bypasses the GFCI, hence the GFCI thinks all the current through that light bulb is actuall going to ground.,

  6. #6


    You need to pigtail a couple of jumpers off the hot and neutral entering the receptacle box and connect them directly to the GFCI. Don't route the lamps through the GFCI. I am pretty sure you are only supposed to protect other receptacles using the GFCI, not lamps.

    It looks like the reason you are tripping is because the neutral of the bottom lamp returns to the input side of the GFCI but the hot for the bottom lamp comes from the output of the GFCI.


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts