I just bought a GE Z-Wave dimmer and the I went to install it I noticed that the previous switch did not have a ground wire attached to it. The new switch says that it requires a ground switch (and obviously I want to install the switch safely). Is there anything I can do to properly ground it?

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Pigtail the ground to the box

It looks like the original installer did a pretty sloppy job of installing the cables (the damaged "redhead" insulating bushing top left is evidence of that"). That aside, the BX armor should be grounded, so by extension, the box should be grounded via the armor.

This means that you should connect the ground screw on the switch to a 10-32 machine screw threaded into one of the holes in the back of the box using a bare or green #14 wire pigtail. Your average big-box store will carry pre-made-up ground pigtails that you can just screw into the back of the box then attach to the ground screw on the switch, or you can make your own with a 10-32 machine screw and a length of 14AWG wire that's been shucked of its insulation by looping one end of the wire around the screw.

  • +1 brings me back to the bad old days when bx was required in NYC. Hated it! When NM finally was accepted, life vastly improved. – bib Dec 21 '17 at 2:10
  • thank you! what would be the best way to install the 10-32 screw into the box (for someone not so technically inclined)? – Isaac Mizrahi Dec 21 '17 at 3:30
  • @IsaacMizrahi -- there are holes in the back of the box you should just be able to screw it into (with the breaker for the circuit turned off of course!) – ThreePhaseEel Dec 21 '17 at 3:54
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    The leftmost or rightmost hole may be tapped 10-32. You can add a hole and tap it yourself 10-32 if you like, don't put it on the knockout. Do not use a sheetmetal screw. – Harper - Reinstate Monica Dec 21 '17 at 8:31
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    Maybe I missed it in the text/comments, but has anyone suggested that the OP verify continuity to actual ground with a multimeter? – Aloysius Defenestrate Dec 21 '17 at 15:11

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