Hello.

I'm doing some ceiling repair work, will also want to replace a light fixture as well.

Photo of the wire box with the old light. I haven't removed the old light yet.
http://i.imgur.com/I7ikYFY.jpg

It appears that my ceiling wire box only have a black hot wire and a neutral white wire. There is no copper ground wire. The new flush ceiling light I bought do have a copper ground wire, which I'm suppose to screw into the mounting bracket together with the wire box's ground copper wire.

I understand that some older houses (like mine), may not have a copper ground wire, or the metal box it's self is already grounded. I'm not looking to check if the box is grounded or run a new ground wire, I just want to replace the ceiling light fixture.

My question is, what should I do with the copper ground wire from new light?

1. Should I just screw the copper ground wire into the mounting bracket anyways as per instruction? even though there is no copper wire from the wire box.

2. Only connect and cap the white and black wire? Maybe cut the copper ground wire so it doesn't get in the way?

Thanks.

 

How old is the house? Since this is not conduit, and it appears to be NM cable, you may not have a ground due to age. Do you have access above this fixture box? If so, can you tell us if there is a metallic cable covering on the wires, rather than plastic? If so, the metallic covering is your ground and you would just attach your fixture ground to the inside of the box with a green grounding screw, available at most box stores.

 

The house is ~50 years old. I have cable covering that appear to be made out of dark colored weaving. No idea if it is metallic covering or rubber.



Here's a very rough picture of it. Please ignore the hole in the ceiling, that's whole separate can of worms.

Thanks.

 

Nope, you have non grounded cables (two wire), so you don't have a ground. There is no need to cut the grounding wire in the fixture, just wrap it in a ball and place it in the box out of the way of any energized connections. You may want to tape the bundle.

 

Ah, okay.

Just curious, if I did screw the light's ground wire to the mounting bracket, and not have it connect with any other wires, would it do anything? Since mounting bracket is metal, the screws are metal, and the base of the light is metal, they are already touching anyways no?

Thanks.

 

It wouldn't provide the safety of the grounding wire. The path of the ground must go all the way back to the panel and to the grounding electrodes. Just attaching it to the metal box doesn't take the ground anywhere. But for a warm and fuzzy, it won't hurt anything.

 

Looking at your picture it appears there is a ground wire tucked in the back of the box. It is bare. I circled it in green.