I recently removed a crossbar from one of my ceiling pan junction boxes and replaced it with a hickey. As I understand it, having the crossbar was a bit odd since a mounting stud was already available. But, I wonder if the crossbar was there specifically for the sake of grounding.
I replaced the crossbar with a hickey attached to the mounting stud/bolt/screw in the ceiling as illustrated in these depictions.
This worked great. However...
The crossbar had a green 10-32 ground screw in it. There is no such ground screw in the junction box now that the crossbar is gone and the hickey is in place. The ground wire from the chandelier was connected/fastened to the ground screw on the crossbar. There are no ground wires at all in the junction box. There is no place for a ground screw in the junction box.
It seems common in Chicago (where I live) to find that the junction boxes in a home don't have ground wires. It seems most likely that the box is grounded through the metal conduit.
What would be an ideal way to handle this chandelier ground wire now that I have no obvious place to connect it?
Coil it up and tuck it away in the junction box, or otherwise leave the wire disconnected (though keeping in mind that this could be a safety risk or illegal)? Drill/tap a hole for a ground screw in the junction box?
This and this lead me to believe that although the mounting hardware may have seemed redundant, the mounting strap was indeed performing a necessary function before, and that a saftey risk is now present without that ground wire being connected.
Yes, metal-metal contact between parts is acceptable grounding if all these are true:
- the mounting bracket is bottomed out "hard" against the metal junction box (not dangling by the screws or floating on drywall ears, as is usually the case with receptacles and switches)
- and both are clean bare metal (not contaminated with paint, rust etc.)
- and there are no insulators in the way (those little squares that outlets use to capture screws).
These conditions ^ were present with the previous crossbar assembly.