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GFCI Outlet Installation

Discussion in 'Electrical Engineering' started by David, Apr 3, 2005.

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  1. David

    David Guest

    I just installed a GFCI outlet in my bathroom. There are five wires that
    connect to the outlet, 2 line, 2 load, and a ground. When I connect the
    line wires to the line terminals and the ground wire to the ground terminal,
    everything works fine. I get power. But when I then connect the load wires
    to the load terminals, the reset switch keeps tripping and the power keeps
    shutting off. I'm not sure why this is happening. Any ideas? I don't think
    that there are any loads down the line from the GFCI outlet, so I'm
    thinking that maybe I should just cap the load wires and call it a day. Is
    this o.k.?

    Thanks for the help.

  2. w_tom

    w_tom Guest

    It is tripping because you have a wiring problem. Fastest
    way to determine the problem is to disconnect all appliances
    from the down stream (load) outlets, then use your multimeter
    to measure for conductivity between neutral and safety ground
    wires. You should not even see megohms of resistance between
    any two (of three) 'load' wires. Meter makes locating this
    problem quick and (more important) decisive. For human
    safety, you want decisive answers; not speculation.
  3. John Ray

    John Ray Guest

    Make sure you've got your line / load right on BOTH hot and neutral. Its
    possible the old one was wired backwards, as older GFCIs would operate as a
    regular receptacle if wired wrong. The newer models will not. Easiest way to
    check is look for continuity between neutral and ground on the line side.

  4. Paul A

    Paul A Guest

    Actually, it appears that the new ones will act as a regular receptacle when
    wired backwards. I just did that with a brand new Leviton "Smart Lock" GFCI
    (don't ask), and it was a live outlet. Neither the Test not Reset buttons
    did anything. When I got line and load where they belonged, Test and Reset
    worked as they should.

    The instructions claim that they are shipped from the factory so they have
    to be reset before use and will not reset when wired incorrectly, but that
    was not my experience.

  5. David

    David Guest

    It looks like everything is wired right. According to my instructions, if
    you connect the line wires to the load terminals, the receptacle will still
    operate, but it will not trip (shut off) when you push the "test" button
    like it is supposed to do I just tested the continuity between the neutral
    (white) and ground wires. It measured 0.


  6. w_tom

    w_tom Guest

    You tested 0 ohms between neutral (white) and ground.
    Therefore GFCI complains about defective wiring. A wiring
    problem that may have existed since the house was first
    built. Find that short in one of the 'downstream' (load side)
    wall receptacles. Open each cover plate and inspect for a
    short between ground and neutral wires. And then confirm,
    with meter, that the short has been eliminated. If necessary,
    electrical tape those wires as well as separate them.

    BTW, if any of those receptacles are powering computer
    equipment, then every wire should be firmly attached via
    receptacle screws on side; not connected by pushing into the
    back. Each wire must be firmly wrapped around screw so that
    it remains there even if screw is loose. Insulation on the
    white wire should have never made contact to bare copper
    safety ground. IOW the GFCI trip may be a symptom of a bad
    electrical job inside one of those 'downstream' (load side)
    wall receptacles.

    Only white and neutral wire that should measure 0 ohms is
    the wire that goes to breaker box. Wires that connect to the
    GFCI's 'Line' screws. Those wires that connect to 'Load'
    screws must measure infinite ohms (no conductivity). GFCI
    will detect these wiring defects.

    GFCI will not trip off when test is pressed? Did you
    properly identify 'load' and 'line' wires? This can be a
    symptom of reversed wires. But then this is also why you have
    the meter. Use meter to determine with wire pair has 120 VAC
    when circuit breaker is on. This would be the 'line' wires.
  7. David

    David Guest

    No.. I appreciate the suggestion. I like to install things, troubleshoot
    problems on my own, whenever I can. I learn that way. Sometimes, though.
    I've found it's better to let a professional do the install/repair or at
    least watch a professional do it the first time around to see how it's done.
    I definitely don't need a house fire, damaged electrical components, or a
    possible electrical injury.

  8. David

    David Guest

    Just a couple things.. The 0 ohm reading was between the line neutral (hot
    wire) and the ground wire . The reading between the load neutral and ground
    reads infinite. Is this o.k.? I'm sorry if I didn't make this clear. You
    write about the wire holes and the wire screws on the receptacle. When I
    the installed the GFCI, I pushed all of the wires (2 line and 2 load)
    through their respective holes. Was this a mistake? There are holes
    besides each line and load screw.


  9. John Gilmer

    John Gilmer Guest

    Are you saying that the GFCIs that "clamp" the wire as you tighten the screw
    aren't "good enough?"
  10. John Ray

    John Ray Guest

    I think that statement was in reference to inspecting the standard duplexes
    that may exist load-side of the GFCI, In which case I agree with him

  11. Guest

    It is ok. Cap it, and see what doesn't work. There has to be *something*
    downstream (ie electricaly farther away from the voltage source) because
    you have wires going out as well as coming in. You might find that a seldom
    used receptacle - perhaps in the garage or outdoors is dead. When you find
    something that doesn't work in the future, remember the capped wires. When
    you call the electrician in to fix it, tell him about the bathroom GFCI
    & capped
    wires. That will reduce the repair time.

  12. Guest

    If this was the newer type of GFCI (probable) then the right way is
    to install the wires in the holes - NOT to wrap them around the
    screws - and then tighten the screws. Tightening the screws on
    this style GFCI receptacle clamps the wires. Simple to check - if
    the screws are loose, the wires pull out of the holes easily.

    Unlike it being ok to cap the load side wires, it is NOT ok to
    leave those screws loose!

  13. w_tom

    w_tom Guest

    John Ray has corrected a misconception. All those other
    wall receptacles, if powering things that require high startup
    currents (ie electric motors) or computers should have wires
    wrapped completely around the screws; not use the push in
    holes on the back of conventional wall receptacles. That was
    not a reference to GFCIs that can only connect using screws.

    Dave has apparently modified an earlier post. There is no
    conductivity between any two 'load' side wires. He was
    measuring neutral to ground on 'line' side. BTW the
    conductivity meter must be set to read in the megohm region -
    not just measure for short circuit. The 'beeper on a meter'
    is not a valid reading. The meter must read more than a
    megohm resistance which is more than testing for a short
    circuit. Dave may have done this correctly. But if he has
    not measured a leakage, then other problems may exist such as
    a leaky capacitor installed in some receptacle as a noise
    reducer or some other problem causing a non-linear leakage.
    For example, a 1000 ohm resistance between two wires would not
    'beep' the conductivity tester but would be resistance so low
    as to always trip the GFCI. 100K ohm resistance might cause
    marginal GFCI tripping. But the resistance between two wires
    much be more than 1000K ohms. Anything at or less is
    considered a short circuit - to the GFCI..

    Non-linear in this case would mean a leakage between two
    wires does not exist when at low voltage (ie using a meter)
    but exists when a higher voltage or a higher frequency current
    is applied. Inspector for something unusual in that electric
    box (ie electronic bugging device).

    Other possibilities could include a short inside walls from
    the white neutral wire to, for example, some adjacent pipe.
    One way to check for this fault is to measure for high megohm
    resistance from each 'load' side wire to the safety ground
    wire on the 'line' side cable.

    This we know. Something is leaking excessive current. If I
    read the post correctly, this leakage only exists when the
    'load' wire is connected to 'load' screws on GFCI. But I am
    rather confused about another post where the test button does
    not work. That is a different inconsistency.

    I am rather concerned about a GFCI not tripping when the
    test button is pressed. One reason why this can happen is
    that the 'load' and 'line' wires are reverse connected to
    GFCI. Another reason observed is that the 'load' side neutral
    wire was wrapped together (wire nutted) with a neutral wire
    from some other circuit. I have seen amateur electricians do
    this. Two switches were to be powered by different circuits.
    But the electrician wired all neutrals from both circuits
    together. When asked why he did this, well, he always did
    this for years. It was only when AGFIs were required by code
    that his circuits had strange problems.

    IOW be suspicious of any receptacle or switch boxes that
    control power from two different circuit breaker circuits.
    Just another reason why the GFCI would see a failure and

    Again, we do know one thing. The GFCI sees and is
    complaining about a wiring problem. It could be a problem
    existing for decades - before the GFCI was installed.

    How do electricians learn of the wiring schematic? They use
    testers that put radio waves on those wires, then follow the
    wires inside wall with a 'receiver'. They cost as low as $20
    even in Radio Shack. However, with experience, the meter, and
    process of elimination, one can also figure out (discover) how
    each circuit is wired.
  14. Guest

    Tom - look at a new GFCI. The new ones should NOT be wired
    by wrapping the wire around the screws. The wires SHOULD be put
    in the holes in the back, and the screws must be tightened. These are
    not the "push-in" holes you are thinking of. Those make contact with the
    wires via spring tension. The newer GFCI's have a clamp in the holes,
    which is tightened onto the wires when you tighten the screws.
  15. Guest

    Yes! Home wiring diagrams don't exist until you make one - and
    you can't make one that includes the wires that are capped off.
    The closest you'll get - until you make your own - is looking at the
    labeling that is supposed to be at your service panel.

    But all is not lost - in making your own diagram, you are likely to
    find out where those capped wires go. To make a diagram:
    draw each room on its own piece of paper. Mark *EVERY*
    outlet. An "outlet" is any place where a device can use
    electricity from you house wiringt, not just receptacles. Mark
    the diagram with every light, switch, receptacle and hard-wired
    appliance. Don't forget to mark the thermostat and doorbell
    transformers - you'll need to search for them. You'll also need
    to make a diagram that shows *ALL* outdoor outlets. With a
    helper at the panel, go from room to room with your diagrams,
    and mark the breaker number that kills the power to each and
    every outlet. Use a 3 lite tester to test for power at the receptacles.
    It is much easier and better than a multimeter for this task.

    In the process, you should find something that does not work.
    If you do, it is highly probable that it is connected to the wires
    that are capped. When you are done with the diagrams,
    put them on the PC and print them. Then make one more -
    a diagram of your service panel showing *EVERYTHING*
    that is connected to each breaker. Tape a clear sheet of acetate
    on the panel and put the diagram inside. You don't need
    a CAD program for this - anything that allows drawing rectangles
    and adding text will work - even a word processor.

    The next time you have a problem, there will be no guesswork
    needed. It takes a few hours, but it is well worth the effort.

  16. Roy Q.T.

    Roy Q.T. Guest

    GFCI Outlet Installation

    Group: Date: Sun, Apr 3, 2005, 3:09pm From:

    I just installed a GFCI outlet in my bathroom. There are five wires that
    connect to the outlet, 2 line, 2 load, and a ground. When I connect the
    line wires to the line terminals and the ground wire to the ground
    terminal, everything works fine. I get power. But when I then connect
    the load wires to the load terminals, the reset switch keeps tripping
    and the power keeps shutting off. I'm not sure why this is happening.
    Any ideas? I don't think that there are any loads down the line from the
    GFCI outlet, so I'm thinking that maybe I should just cap the load wires
    and call it a day. Is this o.k.?
    Thanks for the help.
    You know,the same darned thing happened to me Frist time, but with a gfi
    20A circuit breaker., I opened a plateded old fuse box, now a splice
    through, I found I had 2 different circuits on the same ground (neutral
    white wire) the wires are covered with threads but the rubber inside is
    still fine....... So I made a run of 12awg white stranded for the new
    circuit & left the piggyback on t's won circuit and isolated it from my
    gfi Kithchen/Bathroom Circuit and the GFI Breaker finally ReSet.

    on gfci receptacles i find it hard to connect the line to the load side
    (the loadside has a deeper groove), but with the mix of travelers and
    adjacent circuit cables, it could happen to anyone I think it's best to
    spice pigtails to the gfci taps/screws and attach from there , this coud
    be a time saver if you have 1 or 2 fed-through wires and are attaching
    more than 1 load.

    caped load/end circuits shouldn't affect gfci performance at all,
    reversed condunctors? yes, somethings they're better off on the line
    side, like the lighting circuit in the units....

    oh well back to the books.... i don't worry any more :>) i just do it

    OOP; shheee't still thinking about that stranded no.6 bare neutral to
    ground panel screw-in-lug., no barred earth bonding };-o

    ®oy cet
  17. John Gilmer

    John Gilmer Guest

    Those make contact with the
    Some months ago "someone" on this NG was touting a replacement for the
    wirenut that to all appearances is equivalent to the "push in" you see on
    cheap outlets.

    I purchased a recessed ceiling fixture (new work type) that has these
    already "in the box" but I haven't used it yet. I haven't seen them at
    the local BIG BOX store but I haven't looked lately.

    Problem is, of course, is when "they" start selling GOOD "push ins" many
    folks will remember the NOT so good "push ins." Maybe that's why I don't
    see them at HD.
  18. Most of the GFCI receptacles you are talking about are listed to be
    wired either way. The Leviton rear clamping type is listed for either
    termination method for example. If the device is not listed for side
    wire by using the screws the screws would be tightly shrouded by the
    plastic housing to make mis wiring difficult.
  19. David

    David Guest

    Interesting.. I live in a small 2 level townhouse. There are 3 breakers
    (switches) labeled "lighting" in the breaker panel. One of those breakers
    controls the downstairs lighting, and the other 2 control the upstairs
    lighting. There are other breakers in the breaker panel labeled range, A/C,
    water, dryer, etc., and one labeled "main" that shuts everything off. I
    tested all of the upstairs receptacle and switches that are controlled by
    the same breaker as the GFCI receptacle. They all tested normal. Could a
    problem with a receptacle/switch controlled by one breaker cause a problem
    with a receptacle/switch controlled by another breaker? If yes, how might
    that happen? If possible, please explain it to me at the high school level.
    I know the basics of series/parallel circuit design, but not much more.

    Thanks for all of your help (everybody),

  20. w_tom

    w_tom Guest

    One answer was posted previously. This is simple point to
    point wiring. Nothing that requires an advanced education.
    But translating simple diagrams from and to text requires
    careful reading. Now that answer which but one example:
    Wire wires from different circuits connected together will
    not trip conventional circuit breakers but will be detected by
    GFCI units.

    BTW, if you have determined the circuit breaker number for
    each outlet, then simply write that circuit breaker number on
    the inside surface of each cover plate. If one need ever turn
    off power to fix a receptacle, then he knows immediately which
    breaker to cut off.
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