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  1. #1
    Elite Member
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    Grayson County, TX
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    Kubota B2710

    Default GFI Outlet wiring

    I discovered a GFI outlet in the master bath in our new home would not work. Funny, because the green light was on but there was no power in the outlet itself.

    I tried resetting the outlet and the reset button would not stay seated, thus the outlets remained in a tripped state, but the green light on. After several tries I managed to throw the circuit breaker back in the breaker box.

    With the power off, I pull the cover off and checked voltage. If found that the top terminals had power but the bottom terminals had none. There were two whites & two blacks connected on the top (where the power was) and only one of each on the bottom.

    Figuring it must be a bad outlet I drove 10 miles and picked up a new one, identical to the one in the wall. When I took a look at the wiring I discovered that it appeared to be wired wrong. The wires with power were connected to the "load" terminal, while the wire with no power were connected to the "line" terminal.

    I carefully marked the wires connected to the "line" terminal so as not to get them mixed up. I then rewired the outlet, connected the wires with power to the "line" terminal and the wires with no power to the "load" terminals. Unfortunately at this point there was still no power in the outlet, and the green light was off. So I pulled it off and installed the new outlet the way the old one was wired with the same result - green light on, no power in the outlet.

    I then decided to wire it the the way it should be wired, but this time I left off the wires with no power, so there is nothing connected to the "load" terminals. The outlet then worked, the green light is on, and the test and reset buttons work.

    There are two things I noted besides the fact the outlet was apparently wired wrong:

    1. The electrician left NO slack in the wires so it was very difficult to get the wires connected. In fact, to connect the load terminals I would have had to turn the outlet upside down!

    2. There is at least one outlet nearby that runs off the hot terminal (so no protected by the GFI). This means there are two white wires and two black wires NOW on the line terminals (were originally on the load terminals) But one of the wires is a smaller guage than the other making it near impossible to get the screw clamped down on both wires. Once it tightens on the fat wire, the skinnier wire kept slipping out until I got a BIG screwdriver and put alot of force on it to compress the copper of the fatter wire.

    Now, I know I have disconnected the wires that go downstream that are supposed to be protected. I'm sure these wires have never had any power, and this outlet has never been tried before today. But even with these wires disconnefted we can't find anything that doesn't work!

    Is there any explanation for the way this thing was wired. I read somewhere that electricians sometimes wire these things backwards for a reason, but it wasn't working and now it is.
    Alan L., TX
    South of Bugtussle
    North of Mustang
    On the banks of Buck Creek
    We don't rent pigs.

  2. #2
    Super Member Robert_in_NY's Avatar
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    Default Re: GFI Outlet wiring

    I am not good enough to tell you what is wrong over the internet but I will tell you this, some electricians do some stupid things and some just have brain cramps. Call up the guy who wired it and ask him to fix it.

    As for the short wires, a lot of electricians do this trying to save a couple dollars in wire. Others do it just so they don't have as much wire in the box. I try to leave around 6" so the outlet can be pulled out from the wall a few inches.

    Good luck


    God must love stupid people; He made so many

  3. #3
    Veteran Member
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    Lecompton, Kansas
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    AgKing 2840 shuttle shift

    Default Re: GFI Outlet wiring

    Alan, I would check out the wiring in the "load" side of this, it appears from your explanation that there is something wrong there. If you leave it unhooked or bypass the GFI, it stays on. Are there only one set of wires going to it or does it branch to another circuit?
    WmWms

  4. #4
    Veteran Member SpringHollow's Avatar
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    Power Trac 1850, NH 2120

    Default Re: GFI Outlet wiring

    Is the GFI tripping right away? - maybe there is a short downstream of the outlet you are installing.

    You could try leaving those wires disconnected and install another outlet leaving it and the GFI dangling out of the box. Make sure not to touch any hot wires/connections when testing - you could play it safe and wrap the edges of the outlets in electrical tape. If it works properly, then there is a problem with the wiring downstream.

    If it does not, then you are wiring it incorrectly.

    Before even trying that, you could turn off the breaker and measure conductivity between the hot and ground and the neutral and ground of the downstream wires to see if you can measure a short.

    At work about 15 years ago, I insisted on GFIs being installed in a large renovation we were having done. Everyone said no - problems with nuisance tripping. But I insisted and they were installed. When they turned on one of the circuits, the GFCI breaker tripped immediately. Kept tripping so they said they were right and were going to swap it out. I stopped them and started checking for shorts. Sure enough, a whole run of metal casework was live because an integral drying oven had a hot wire touching the casework. We did a test and installed a regular breaker. The short did not pull enough current to throw the breaker. If they had installed a regular breaker to begin with, it is possible the first person to touch the metal casework could have been injured or worse. My whole house is now GFCIed. If the combination arc/GFCI are reliable, I will switch over to them.

    Ken

  5. #5
    Elite Member ToadHill's Avatar
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    Default Re: GFI Outlet wiring

    I'm not sure if this is normal but with my farm house if one GFI outlet trips, it shuts off all the GFI's in the house.
    I can't control my day but I can control my attitude.

  6. #6
    Veteran Member SpringHollow's Avatar
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    Default Re: GFI Outlet wiring

    That would imply that everything is run off of that one GFI - not a very good setup. Lights should not be on the same circuit as appliances, etc.

    Do you ever trip due to overloading?

    Ken

  7. #7
    Super Member Robert_in_NY's Avatar
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    Default Re: GFI Outlet wiring

    Quote Originally Posted by ToadHill
    I'm not sure if this is normal but with my farm house if one GFI outlet trips, it shuts off all the GFI's in the house.
    Paul, this is normal as GFI's are designed to run in series so you also can get by with a normal outlet ran off the load side of a GFI and the normal outlet would be protected by the one GFI.

    Just how many outlets did they run off the one GFI though?


    God must love stupid people; He made so many

  8. #8
    Veteran Member gordon21's Avatar
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    Default Re: GFI Outlet wiring

    If I read your description right, the input side has 2 black wires. One is feeding the GFI and the other is now bypassing the GFI and heading elsewhere. The other outlets and lights are wired in parallel, not in series. A GFI only works and protects if everything is downstream from it. Both white and black wires must go through the GFI, and nothing going around. There should only be one white and one black on the input or line side. You MAY have multiple wires on the load side, since it is downstream from protection.
    Lewis Gordon

    JD 790, 300 FEL, 5' KK rotary mower, 5' boxscraper, Huskee 3PT logsplitter, JD#39N sickle mower and a Jinma 6" chipper in JD colors.

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  9. #9
    Elite Member ToadHill's Avatar
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    Default Re: GFI Outlet wiring

    Robert: 6, one outside, 3 bathrooms, 2 in the kitchen.
    I can't control my day but I can control my attitude.

  10. #10
    Super Member JB4310's Avatar
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    Central CT
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    J.D. 4310 E-hydro

    Default Re: GFI Outlet wiring

    Quote Originally Posted by Alan L.

    2. There is at least one outlet nearby that runs off the hot terminal (so no protected by the GFI). This means there are two white wires and two black wires NOW on the line terminals (were originally on the load terminals) But one of the wires is a smaller guage than the other making it near impossible to get the screw clamped down on both wires. Once it tightens on the fat wire, the skinnier wire kept slipping out until I got a BIG screwdriver and put alot of force on it to compress the copper of the fatter wire.

    Now, I know I have disconnected the wires that go downstream that are supposed to be protected. I'm sure these wires have never had any power, and this outlet has never been tried before today. But even with these wires disconnefted we can't find anything that doesn't work!

    Is there any explanation for the way this thing was wired. I read somewhere that electricians sometimes wire these things backwards for a reason, but it wasn't working and now it is.
    I don't think electricians wire things backwards on purpose, but it does happen, I've seen electricians wire direct shorts, turn on the breaker and boom!, I've made mistakes, heck doctors amputate the wrong limbs.

    Sounds like it was just a mistake, if that other outlet that's nearby which is not protected is actually in the bath room then connect it to the load side of the GFI, then it will be protected by gfci also, you say it's one of the wires off the hot terminal now, this is just a guess but probably the smaller wire, most likely a 14 GA.

    That still leaves the mystery wire, could have been an extra not used for anything, was roughed in but plans changed, when electrician did the finish work he thought it was the line from circuit box and the other two were loads, just like you found it. It could be a feed for something else you have not discovered yet not working and belong on the load side
    JD 4310; E hydro, 300CX, 48 BH, 60" box, 72" rake, 72" rear blade, cast pallet forks, 48", 61"HD & 73" high volume bucket.
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