We are in the process of replacing the ballast in our fluorescent light fixture (after replacing the bulbs, the lighting was still dim, so we figured it was a fault of the ballast). After we disconnected the hot and neutral (black and white) wires from the ballast, we noticed a third, unused wire coming out of the wall. Here is a picture:

unused wire from wall unused wire from wall

Our ballast does not appear to need this wire. What we want to know is:

  1. What is it?
  2. Is it dangerous to leave it exposed like this? It is basically just 'hanging out' behind the fixture; we didn't realize this until just now.
  3. If it IS dangerous, what can we do to make it safe?

1 Answer 1


This is a ground wire. No wires should be left exposed hanging out of the wall. It's not going to spontaneously burn down your house like that, but it could possibly become energized in which case it would pose a risk if someone were to make contact with it.

The fixture should have a grounding nut and that wire should be secured to it. Look for a green colored screw (not guaranteed to be green, but makes finding it simple).

In the event the wire really isn't needed, the wire should be neatly folded up within the electrical box (or the wiring box on the fixture itself).

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