I have a ballast that runs 2 250w metal halide bulbs, would leaving one socket empty harm the ballast? I’m assuming it’d cut the power usage in half, wouldn’t it? One bulb would be enough for the first three months or so of use, plugging in the other bulb later on when the full 500w would be needed.
Give me dope…err…the straight dope.
I don’t know about that kind of bulb, but at work we left a dead flourescent bulb in a fixture because it was hard to get to, and the ballast burnt out soon after.
The hardest stress on a ballast comes from leaving a dying flourescent tube in it – one that is flickering. Each flicker is an attempt by the ballast to light up the tube. (Plus it’s annoying as hell to everybody around it.)
Leaving a dead tube in may be hard on the ballast, because it might not be completly dead and the ballast is still trying to light it, even though it’s dead enough to not actually flicker visibly.
If it really is completely dead, then the circuit is open, and is not putting stress on the ballast. Just like removing the tube, then for sure the circuit is open.
So it’s best to remove a flourescent tube, and leave it empty until you replace it with a new tube.
I’m not sure about the newer high-intensity bulbs.