If you’re changing out a light fixture and find there’s no ground wire in the box, you’re not out of luck. Here’s how to connect a 2-wire light fixture without ground.
If you’re having trouble locating the ground wire, the ground wire is either a bare wire or green.
Always turn off the power at the breaker or fuse box before you work on electricity. This keeps you safe from potential electric shock.
The purpose of the ground wire
The ground wire is designed to protect you. In the event that the live wire comes loose and touches the light fixture, the ground wire diverts the power and blows the breaker, instead of you feeling an electrical shock when you touch the fixture.
That’s the only purpose the ground wire serves. It’s a safety feature. The light works just fine without it, just like in the case of a light switch. But before you just discard it entirely, there may be an alternative way to hook it up.
Examine the metal box
Assuming the electrical box is metal, take a look at the box. Frequently the metal box itself is grounded. If the Romex wire coming into the box appears to have a metalized surface, that surface probably serves as a ground. I’ve also seen boxes where the ground wire is looped back so it’s touching the box but not actually present in the box.
While you can’t necessarily assume every metal box is grounded, many are. If there’s a screw inside the metal box, connect the ground wire from the fixture to it. If not, look for a screw hole in the box. You can put a short 8-32 machine screw in the hole, then connect the ground wire to that screw.
Putting a screw in an electrical box can be a pain. I find a magnetized screwdriver helps. If you don’t have a magnetized screwdriver, try using a small piece of tape to secure the screw to your screwdriver until you thread the screw into its destination.
Last and least, if there’s no screw present in the box to connect a ground wire and no place to put a screw, here’s a workaround. Remove one of the long screws that holds the fixture in place. Thread an 8-32 nut onto the screw. Replace the screw. Wrap the wire around the screw, then cinch the nut down to hold it.
A plastic box with no ground
What if you find a plastic box with no ground? I’ve seen people ground to plastic before, but it doesn’t do any good. You’re just as well off leaving the wire unconnected as you are trying to ground to plastic. You can wrap the wire around one of the screws that holds the fixture on, but the only purpose it serves is to help hold the fixture up while you wire the black hot and white common wires.
Never do this
Never, ever, EVER connect the ground wire to the white wire. I’ve seen people do this as a workaround when there’s no ground available. But this connection isn’t the same as ground, so don’t do it, as it greatly increases the chances of the fixture becoming electrified.
I’ve had a few too many adventures with ceiling light fixtures. Here’s what to do if your ceiling light fixture doesn’t work, how to add an outlet to a light switch line, and what to do if you find both a red and black wire.