The light dimmer of my chandelier broke recently so I went buy a new one (incandescent 120 V 600W). The one that broke was fairly old (sticker on the dimmer mentions 1987).

Since I'm pretty novice about electrical stuff I took a few picture before installing the new one.

As you can see it is sharing the wallbox with a light switch and there was two black wires connected in the wall. The dimmer I bought has a third green wire for grounding. What should I do with this third wire ? For now I capped it and it's working fine but I'm concerned about safety. Shouldn't this be connected somehow ? If so where ? I'm not sure that the wall box itself is grounded.

Thanks in advance for your help.

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  • 1
    There were wire nuts on the two black wire joins of the old dimmer - right?
    – Michael Karas
    May 19, 2015 at 11:28
  • It's difficult to tell, but it doesn't look like there are any grounding conductors in the box. Can you confirm that there are no green or bare wires in the box? It also appears to be a plastic box, is that correct?
    – Tester101
    May 19, 2015 at 13:56
  • @MichaelKarasyes there were, I removed them before taking the picture May 19, 2015 at 14:03

1 Answer 1


Since there doesn't appear to be any grounding conductors in the box, and the box appears to be plastic. You've done all you can do, aside from installing a nonmetallic cover plate.

This answer might also be helpful.

If you're concerned about it, consider that it's been operating without a ground since the switch was originally installed. If you're really concerned, you could install a GFCI breaker to protect the circuit. If you're really really concerned about it, you could install an equipment grounding conductor from the panel to the switch.

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