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My ceiling metal junction box has 2 white wires(twisted together) and 1 black wire. No copper or ground wire inside that I can see? The new fixture has a black, white and green/yellow ground wire. The provided new metal mounting strap bracket does not have a green ground screw. What can I attach the green/yellow ground wire from the fixture to??

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  • Can you post photos of the inside of the ceiling box please?
    – ThreePhaseEel
    Apr 9, 2021 at 11:36
  • Given the confusion below, can you elaborate where this installation is located?
    – erebus
    Apr 10, 2021 at 19:49

3 Answers 3

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Although 2 whites and a black would be unusual. In the US code allows for a grounding conductor to be pulled from the service, or any point fed from that service panel.

2 wire fixtures did not have grounds for the first 75 years of electrical code so many fixtures were not grounded.

If fed by conduit and individual wires the box may be grounded through the conduit.

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  • Not every conduit and in some states any conduit approved as ground.
    – user263983
    Apr 9, 2021 at 18:11
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    @user263983 this is true, and some flexible metallic that was used in the past is no longer code, non metallic is not a ground method but that’s fairly obvious.
    – Ed Beal
    Apr 9, 2021 at 18:34
  • In the case of a 2 wire ungrounded system, if updating wiring is not an option, the circuit can be GFCI protected.
    – K H
    Apr 11, 2021 at 9:28
  • Yes if you add GFCI protection you can install 3 wire receptacles, the receptacles require a sticker stating GFCI protected no equipment ground. Note, in this case the test button will work on the GFCI device but a plug in tester will not trip the device because lack of a equipment ground. This advice is based on the NEC. I should mention not all lighting outlets require a ground since the op is asking about lighting and lighting circuits do not require GFCI, lighting fixtures that don’t have exterior conductive parts do not require a ground.
    – Ed Beal
    Apr 11, 2021 at 15:32
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All metal parts has to be grounded. Check carefully your junction box, bare copper wire should be connected to screw inside the box. You can connect the ground wire from your fixture to same screw or another screw in the box. If you have wiring in your house with ground wire, the metal box body is ground. If the wire from fixture too short, make a jumper. If it is no ground wire, leave the fixture ground wire not connected or may connect it to box screw. Two white wires connected together because the neutral is jumped from that box to another. Connect white wire from fixture to them. An black to black.

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  • @jack edited. Some countries only qualified electrician can make a wires changing. Lack of knowledge can be dangerous.
    – user263983
    Apr 9, 2021 at 18:00
  • Yes, lack of knowledge is dangerous which is why we stress safety and following codes where applicable.
    – JACK
    Apr 9, 2021 at 18:23
  • Correction: depending on jurisdiction and date installed metal parts may be required to be grounded in the US. pre1960 grounding was not required (I did not look up the exact year).
    – Ed Beal
    Apr 9, 2021 at 18:38
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I assume that the two white wires are two lives are for two separate circuits (i. e. two lights, switchable seperately or light+ceiling fan) and the black wire is neutral. In this case, you would connect the ground to the neutral. That's the normal way to do this if you have no ground. However, I would first check what the incoming wires actually connect to. Also you can't have an RCD with this kind of wiring because it would blow the RCD immediately if you touch the grounded parts of your new fixture.

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    Completely off-base for North American wiring...
    – ThreePhaseEel
    Apr 9, 2021 at 11:38
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    Neutral connected to ground only at power source, mainly transformer or main switch. Color of neutral either white or grey, Europe- blue. Black is live wire, phase.
    – user263983
    Apr 9, 2021 at 12:19
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    General message: I'm getting troubled by the electrical advice given when we don't know nearly enough to give good advice/answers. IE: What country are you in? If in USA, what state? How old is the structure you are working on? Let's get the complete picture before posting answers. OK?
    – George Anderson
    Apr 9, 2021 at 14:33
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    @erebus I don't mean to be rude, really, and I'm sorry to have to say this, but if you don't know if "North America has an ungrounded power grid" or not, you are completely unqualified to answer electrical questions. Yes, America has a grounded power grid where the neutral is grounded. It's been that way for about 120 years.
    – George Anderson
    Apr 9, 2021 at 14:53
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    Yeah, given the metal box and odd number of wires, OP is certainly in a conduit system. A metal box all but implies metal conduit, and in North America, metal conduit carries ground for you (the Soviets were into that too). In these installations you don't see apparent ground wires. But even in your country, neutral is not ground and you do not use them for each other. Yes, I am well aware that you have seen neutral and ground connected to each other somewhere in your system. The crux is the "somewhere".
    – Harper - Reinstate Monica
    Apr 9, 2021 at 16:57

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