Hello, I am trying to install a new light fixture and have a question about the ground wire. The old mounting bracket (picture 1) is the same as the new one (picture 2), so no need to replace that. However, reading the instructions for the new light fixture (picture 3), there seems to be a difference with how the old light fixture (which did not have a ground wire) was installed.

Old installation: the ground wire from the house is connected to the green screw on the old mounting bracket.

Instructions for new fixture: Connect ground wire from new mounting bracket (picture 2) to house ground screw. Then connect house ground wire and new fixture ground wire together.

Question: I do not see a house ground screw. Is it OK to: (a) Connect the both house ground wire and the new fixture ground wire to the green screw of the old mounting bracket? and (b) Do not use the ground wire from the new mounting bracket (seen in picture 2).

A separate question: Why are there caps in the middle of the black and white wires in the new light fixture (picture 3)? I believe I should connect the end of the black wire with the house black wire (and same for the white wires), but is there any reason to have these additional caps in the middle of these wires?

 

You want all the grounds connected together (house wire ground, mounting bracket, and ground from fixture. Since it's sometimes difficult to connect more than one wire reliably to the screw on the mounting bracket, what is often done is to connect the fixture ground, the house wire ground, and a short piece of wire together with a wire nut, and connect the other end of the short wire to the mounting bracket. In your case, if you swapped the mounting brackets you could just tie all three ground wires together with a wire nut.

The wire nuts in the fixture are used to tie two separate sockets together and provide a single wire for connection to the house wiring. They could have just given you two white and two black wires to tie to the house wiring; either way would work. It just makes installation a little easier to have single wires.

 

Thank you! This is very helpful, and I was able to install the fixture.

Two additional questions:

- The ground wire is exposed (picture 3 in the original post), so it will be in contact with the fixture panel, as well as the drywall. Is this OK? The white and black wires are all hidden by the respective wire nuts, but the ground wires are exposed. Will it be OK to touch the fixture panel (the metal rectangle) like that?

- It appears the walls are not level, so when the fixture is installed, there is a gap between the wall and the fixture panel in one corner. Since the fixture is installed over a vanity in a bathroom, should I be worried about moisture reaching the wiring through the gap - and if so, how can I fix that?

 

Yes. The ground wire carries no current except in fault conditions.Depends on the size of the gap. You could caulk it.

 

The gap is ~1/4 inches at its widest (top left corner, picture attached). All of the other three corners are flush. Is it necessary to caulk around the fixture (or any other solution) to avoid moisture getting to the wiring?

 

That is not an uncommon problem especially in older homes.
You don't need to do anything with that gap as far as electrical.
The moisture in the air will not bother the wiring.