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So I'm trying to fit a new light fixture that's got the usual black, white, and copper/green wires coming out from the light itself. However, when I took off the old light and looked at the wires in the electrical box in the ceiling, the black and white are self-evident (see photo), but I cannot figure out where the copper/green wire is for the ground:

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Maybe the previous light didn't make use of a ground?

Or maybe the ground is that there's a mess of wires that are the third set in the photo, besides the aforementioned black and white ones. This mess of wires is a mix of black and white, all coming together into a twist-on wire connector.

BTW I read this one and some related questions, but didn't figure it out... Can I safely ground a light fixture if the ceiling box has two hot and one neutral wire (no ground wire)

Edit: To the request for better/closer photo, I've added a zoomed-in version of the photo above, hope it helps.

  • @keshlam, all the wires appear to be white or black, no green or other colors, unfortunately. It amazes me how there's such an apparent lack of standards in something as important as electrical wiring... – gto Jun 15 '16 at 13:34
  • @kris, that's right, exposed tiny copper wire in the top left. Would this pretty surely be a ground? I didn't want to make assumptions since it's so far back in the box... – gto Jun 15 '16 at 13:39
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Here's my best guess at the wiring based on the photo. Looks like you've got one hot/neutral coming into the box from the panel (or another switch/outlet), and you've got 2 hot/neutrals going out of the box to other switches/outlets. Since these are all joined together, it doesn't really matter which one is coming in and which two are going out.

Then it looks you you have a white wire connected to the bundle of hot wires, and that white is going out of the box to the switch, and then a black wire returning from the switch, which goes to your lamp. This is pretty common, but that white wire should probably be marked at both ends to indicate that it's actually a hot.

Based on what I can see in the picture, you do not have a ground wire. It's possible that the box itself is grounded, either with a ground wire screwed to it that's not visible in the photo or by metal conduit, but based on the yellowed insulation of the white wires, my guess is that your house is old enough that no ground was required at the time, so there is not ground wire.

enter image description here

Update based on your close-up picture, there are ground wires, they are sort of terminated to the box on the strain relief clamps. If you have enough slack, it would be good to wirenut them all together securely with one pigtail that goes to the box and one to your lamp. Otherwise, make sure they are all securely fastened to the box, only one of them (the one that leads back to the panel) is a "real" ground, the others are providing ground for downstream lights/outlets, so make sure that all all them are securely fastened.

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    Ground appears to be bare copper wires running alongside the insulated bundle, sorta half-heartedly wrapped around the strain-relief clamps. – keshlam Jun 15 '16 at 14:31
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Agree with Kris in the earlier post. Look at one of the main wires coming through the conduit in the upper left. It looks like there's a very clearly-cut ground wire that was cut close to the entrance into the box.

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You appear to have older 14-2 without ground coming in from 4 directions, and each of those (or at least three of them) has a separate uninsulated ground alongside. If you combine them and pigtail to the box and your fixture, in theory everything will be protected.

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From the looks of your updated photo, your house was wired with a 50s/60s type of NM that carried an undersized (16AWG) "ground"-but-not-really-a-ground with it. The common practice with these wires was to fold them back into or screw them to the cableclamps instead of bringing them into the box and pigtailing them to a ground screw on the box.

In this case, you likely won't have enough slack in the ground wires to pull them out and pigtail them together -- I'd simply connect the fixture ground to the box with an appropriate grounding screw.

  • Awesome, thank you - that's what I ended up doing. Great community here at stackexchange, thanks so much for the help everyone! – gto Jun 16 '16 at 0:36

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