GFCI grounding issue/question

balee123balee123 Solar Expert Posts: 86 ✭✭
Hi,

Not really a "Solar Beginners" question, but your input and knowledge would be much appreciated.

I wanted to install an extra outlet close to our kitchen island. There is no sink or water source on the island. But I wanted to install a GFCI outlet anyway.

The only accessible source of electricity is a light switch. It appears that when this switch was installed, they did not use any ground wire. There are only hot and neutral lines. I installed a GFCI outlet below this light switch, without using a ground wire, since there isn't one.
Not surprisingly, when an outlet tester was plugged in, it shows "Open Ground" (see pics).

My questions are:

1) can this outlet be used? Can it be used "safely"?

2) Is there anything that shouldn't be plugged into such an outlet?

3) Is there a way to remedy this situation?

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Comments

  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: GFCI grounding issue/question

    It still should work OK. It detects leakage to ground by monitoring the hot and neutral lines for any difference in their current flow. A difference between the two, indicates a leakage to ground and that leakage COULD be through a person, so it kicks off, shutting itself down, along with any outlets or circuits "down stream".
    The downside of not having the box grounded, is that if the incoming hot (feeding the GFI) were to make contact with the box the GFI is in, you COULD receive a jolt, and anything requiring a ground, and is plugged into this GFI, that appliance or tool will not be grounded. That aside, the GFI will provide protection as long as it is not defective.
  • BB.BB. Super Moderators, Administrators Posts: 29,747 admin
    Re: GFCI grounding issue/question

    In older homes wired with two prong outlets, you may find a thin copper wire in the box that needs to be connected to the outlet. That was how homes were grounded in our area decades past.

    You should ground any three prong outlet.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: GFCI grounding issue/question
    balee123 wrote: »
    .

    My questions are:

    1) can this outlet be used? Can it be used "safely"?

    2) Is there anything that shouldn't be plugged into such an outlet?

    3) Is there a way to remedy this situation?

    1. Yes. The National Electrical Code allows for GFCI outlets to be installed on a two wire circuit where they will at least detect a difference between the current going out to the load and the return current coming back and so detect a ground fault. But since the outlet has a ground prong which is not connected to anything, you are supposed to put a label on the outlet something like "No Ground, GFCI protected". You are not allowed to connect the ground prong to the neutral ("false ground") or to a nearby water pipe ("bootleg ground") though.

    2. If you have a hypothetical appliance which requires a ground to work, or it is a single-insulated appliance which expects an internal short to the metal housing to blow a breaker, they will not work safely.

    3. The only way to remedy this situation officially (other than just by labeling as in 1), is to pull new wire which includes a ground from a properly grounded part of the system to the outlet. This may require going all the way back to the electrical panel if no other legal ground is available at an intermediate junction box.

    While we are on the subject, the GFCI will do its job, as proven by the operation of the Test button in the outlet, even though the Test button on a plugin tester does not work.
    SMA SB 3000, old BP panels.
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: GFCI grounding issue/question

    I am guessing you tested the wire to the switch and it was in fact a hot and neutral. It may have just been a drop breaking one leg, the color of the wire doesn't mean much. I don't understand a hot and neutral going to a switch. Could be though.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: GFCI grounding issue/question
    I am guessing you tested the wire to the switch and it was in fact a hot and neutral. It may have just been a drop breaking one leg, the color of the wire doesn't mean much. I don't understand a hot and neutral going to a switch. Could be though.
    Quite right.
    There would never be a situation in which only a hot and a neutral ran to a switch. Unless the only purpose for the switch was to trip a breaker. The one which was at zero volts would be the switch leg going to the hot side of a load.
    But it is quite possible that for other reasons a neutral as well as hot and switch-leg would be in the same box, just passing through as it were.

    And under the latest NEC, to allow for the operation of presence sensors/motion detectors to control lights, the electrician must provide a real neutral to the box of any switch which controls a built-in light. But if that were the reason, there would also be a ground!
    (Now if the wiring is in conduit, with a metal box, the box and conduit may in fact be a legal ground and all you would have to do is add a proper ground connection to the box, attaching to the ground wire of the GFCI.)
    SMA SB 3000, old BP panels.
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: GFCI grounding issue/question

    Sorry, I did not describe the hot and neutral wire situation correctly. I have corrected it in the original post. What I meant to say was that there is no ground wire, only hot and neutral wires in the junction box. And yes, the switch does not have a neutral wire connected to it, only hot.

    Also, this is a plastic junction box.

    Thanks to all for the information.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: GFCI grounding issue/question
    balee123 wrote: »
    Sorry, I did not describe the hot and neutral wire situation correctly. I have corrected it in the original post. What I meant to say was that there is no ground wire, only hot and neutral wires in the junction box. And yes, the switch does not have a neutral wire connected to it, only hot.

    Also, this is a plastic junction box.

    Thanks to all for the information.

    I am curious about just what is connected to the original switch box. There are only two common options in residential wiring:
    1. Individual wires, run in EMT (Electrical Metallic Tubing) which is usually just called conduit, even though true conduit is thicker walled.
    2. Lengths of non-metallic-sheathed-cable (NM), also called by the trade name Romex (TM).

    Older installations may use NM containing only insulated conductors and no ground (NM-2), but in newer construction all that is used is NM with a bare ground wire included inside the sheath (NM-2 w/g). Sometimes a DIYer will just cut off the ground wire, especially if going into a plastic box with a device that does not have a screw to terminate it on, but it is there to be used as a ground only.
    SMA SB 3000, old BP panels.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: GFCI grounding issue/question

    One wiring possibility: Hot & Neutral go to box with switch in it where Hot is interrupted by switch, wiring then continues to light fixture.

    Why someone would have used 14-2 NG I don't know, unless it's old wiring from the days when 'Ground' was something you stood on not something you affixed wires to.
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: GFCI grounding issue/question

    When were the "days when 'Ground' was something you stood on not something you affixed wires to" ?

    House was originally constructed in 1960. There was a remodel done in the mid-80's before we purchased the house. All of the remodel wiring is grounded properly.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: GFCI grounding issue/question
    balee123 wrote: »
    When were the "days when 'Ground' was something you stood on not something you affixed wires to" ?

    House was originally constructed in 1960. There was a remodel done in the mid-80's before we purchased the house. All of the remodel wiring is grounded properly.

    That's just about the switch-over date! Around about that time the "new third wire" and all its mysteries were being disclosed to us. Local/state electrical code may not have been up to snuff then.

    It used to be allowed to snake a third wire through and connect ground that way (for retrofitting old houses). Not sure it would pass inspection these days.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: GFCI grounding issue/question
    balee123 wrote: »
    When were the "days when 'Ground' was something you stood on not something you affixed wires to" ?

    House was originally constructed in 1960. There was a remodel done in the mid-80's before we purchased the house. All of the remodel wiring is grounded properly.

    Was around 1960, perhaps a bit earlier that 2 wire + ground started to be used in my area of Nova Scotia, so could have been some of the older 2 wire only cable still on the go and for sale around that time.
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: GFCI grounding issue/question
    inetdog wrote: »
    I am curious about just what is connected to the original switch box. There are only two common options in residential wiring:
    1. Individual wires, run in EMT (Electrical Metallic Tubing) which is usually just called conduit, even though true conduit is thicker walled.
    2. Lengths of non-metallic-sheathed-cable (NM), also called by the trade name Romex (TM).

    Older installations may use NM containing only insulated conductors and no ground (NM-2), but in newer construction all that is used is NM with a bare ground wire included inside the sheath (NM-2 w/g). Sometimes a DIYer will just cut off the ground wire, especially if going into a plastic box with a device that does not have a screw to terminate it on, but it is there to be used as a ground only.

    The wiring is NM/Romex, no conduit into plastic switch box. It must be the older installation NM with no ground. The home is 1960 construction.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: GFCI grounding issue/question

    The plastic box would be a replacement, as they weren't using those in 1960.
    Look at the box closely; does it have bolts that pull against (unseen) tabs and "ears" on the surface? (Bad description.) There were retro-fit boxes like that: cut hole in wall just big enough, insert box, tighten bolts to wedge against plaster board or lath. Not allowed now, of course. But they were still available as late as the 1980's.

    None of which gets you your ground wire. :blush: You'll have to determine if its worthwhile replacing the old Romex with 14-2/G.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: GFCI grounding issue/question
    The plastic box would be a replacement, as they weren't using those in 1960.
    Look at the box closely; does it have bolts that pull against (unseen) tabs and "ears" on the surface? (Bad description.) There were retro-fit boxes like that: cut hole in wall just big enough, insert box, tighten bolts to wedge against plaster board or lath. Not allowed now, of course. But they were still available as late as the 1980's.

    The local home depot still sells these boxes. They are called "old work" boxes. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: GFCI grounding issue/question
    vtmaps wrote: »
    The local home depot still sells these boxes. They are called "old work" boxes. --vtMaps

    Which means, of course, that they would not be allowed for any work in which the wall is already open so that you could attach the box to a stud, but they can be used for upgrade situations in which the wall will not be opened, but you still have access to find or pull the needed wires.
    It is possible that some local codes do not allow their use even in remodels, but they are quite common and have UL listing.
    SMA SB 3000, old BP panels.
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