What would be the correct way to wire a new light fixture if the electrical box had no ground wire and the fixture did not have a bracket mounting to the box with a ground wire attachment. The fixture has three wires white, black, and green. Securing the fixture to the ceiling is done by putting in two screws in the box and mounting the fixture on the screws through the slots in the base of the fixture.

I searched a couple of websites and came up with this info. Before 1967 no one had ground wires on there fixtures cut the ground wire off and it will work just fine. Older homes do not have a third wire for ground prior to the change in mounting requirements. The screws which attach to the box will ground the fixture when you use them to secure it to the ceiling. Second, If there is no ground wire in the box for mounting consult an electrician for installation. Your electrician would know right off the best way. A ground can very easily be secured. Third, Mount the ground wire on the mounting bracket marked ground with a screw for the light fixture. Lastly, look in the box itself and see if there is a screw you use for ground.

My thought for a code installation for this fixture in my home. Turn off power to the circuit at the box by flipping circuit breaker. Connect neutral to neutral and connect power to power. Since the fixture did not have a ground previous and there is no ground wire in the box . There is no bracket for fixture with a ground on it, also no screw to place a ground wire in the box. If a hole was drilled in the plate mounted to the box where the screws are attached for mounting the fixture and then tapped the ground wire could be attached to the plate with a screw. This would meet the requirements for the code.

As an aside, the ground wire was added to insure the fixture was grounded to prevent it from becoming live if there was a fault since there were factors not figured in before 1967? With the additional ground wire this will insure the fixture is grounded if the wire is attached to an adequate ground source? I'm 99% sure the this would be meet code? If you put a bracket up between the fixture and the box plate and connect the fixture ground wire to it what would be the difference when you put the fixture and the ground wire directly to the box plate? The current would flow the same no?

I want to be 100% sure before I install the fixture.

Is your ceiling box steel or what? Steel boxes do have holes for a grounding screw but may not have a screw already waiting for you to use. If the box is metal you can put a test meter between the box and the black hot wire, if you show a circuit then it is grounded. You can attach your green ground wire to a screw into the metal box. Sounds lke your home is old enough that this is a non-issue and would be grandfathered.

Without a ground wire in the box, it is meaningless to worry about how and why to ground the fixture. Yes, the ground wire was added to run a short back to ground with less resistance than a body. If you can't run a ground wire to the box, the simplest thing is to do it put the crossbar on the box and put the green wire under the connection screw or use a crossbar with a ground screw and connect it to the screw. How old is the house and are you sure it is only a 2 wire supply? Sometimes they would wind the ground around the old fabric sheath and slip it under the clamp. Are the wall boxes also ungrounded? Has anyone put in 3 prong receptacles?

Thanks, The box is metal and it is grounded. I had a self tapping screw so I put in the appropriate hole for the screw and located the ground wire. This was the easiest way. Your might be right about the grandfather clause. Crossed my mind before that it did'nt matter but I figured if they changed code they must have had a reason of some kind. I didn't know the reason was a direct ground rather than the body. Thanks for the info and help. Appreciate it!

Electrical components have been made safer over the years, the reason years ago there was no ground pigtail off each fixture.

To eliminate problems a wire was added over the years.

Technically, a ground screw should be a machine thread screw. Not like yours is the first self tapper used , I have seen worse.

At least you know enough to ground it.


Good question.

I thought since the head of the screw had a large area where the wire was placed and was fastened securely that would have grounded it adequately. I can see why you would want a machine screw for better construction! Thanks.