Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

Had a surprise this morning when I went to turn on my bathroom light and it didn't work. All the incandescent bulbs (4 of them) appear to be fine, and the fan which is on the switch beside the light switch is working.

I've checked and reset all breakers. Before calling an electrician, is there anything else I can do? Is it possible that the fixture has failed since none of the bulbs will light up.

share|improve this question
    
Thanks everyone for the feedback and suggestions. Checked the switch with a multimeter and it looks like it may be a power issue feeding the switch. Oddly the GFCI outlet in the bathroom no longer works, and the test button is dead on it as well. This could be a sign of bigger issues so I'm probably going to have an electrician in to take a look. –  3rdparty Nov 11 '10 at 15:09
    
Had an electrician by to take a look. Apparently the fixture was poorly installed (in a condo, surprise!) and was shorting. –  3rdparty Nov 22 '10 at 20:56

4 Answers 4

up vote 7 down vote accepted

If you have a multi-meter and feel comfortable poking around, you can find out some preliminary info. Take off the face-plate for the switches and check the voltage between the two screws on the light switch. You should see nothing when it's on, and full voltage (120/230/etc) when it's off:

  • If you see no voltage all the time, then there's likely a power problem feeding the switch.
  • If you see full voltage all the time, then the switch is probably broken and can be easily replaced.
  • If you see no voltage (switch on) and full voltage (switch off), then it's probably the light fixture.
share|improve this answer

You already accepted an answer, so I'm assuming this is solved, but I'll throw this out there for others who might have this problem.

It could be that the light is on the same circuit as a GFCI outlet. If the GFCI tripped, it would cause all other fixtures further down the same circuit to turn off as well.

I've had this problem before at my house - we have a bathroom downstairs with a GFCI outlet and another bathroom upstairs (directly above it) that is on the same circuit. If the GFCI trips downstairs, the power to the outlets in the upstairs bathroom goes out as well. Was a bit of a head-scratcher for me the first time it happened.

share|improve this answer
    
+1 great tip. I spent 30 mins playing with a "loose" breaker before realizing that a faulty electric mixer was tripping a GFCI on the branch. –  Steve Jackson Nov 10 '10 at 19:01
    
Thanks - great suggestion, and one that I checked initially. –  3rdparty Nov 10 '10 at 20:14
1  
I've seen people get confused with chained GFCI before. I would avoid chaining, or confine it to one room. –  Jay Bazuzi Nov 11 '10 at 3:28
    
@Jay and I found out the hard (zapped) way that my GFCI was NOT on the same circuit as the lights. Now I have an outlet tester that lights up. –  Jared Harley Nov 11 '10 at 8:13

This can be just a bad switch. I would take off the switch plate, and verify that the switch itself is working.

Easiest is to use a voltage sensing probe. These are tremendously useful tools when you are working with electricity. With the power still on, CAREFULLY remove the outlet cover. Turn the switch off to the light. Now, one of the black lines running from the switch will be "hot", and the other black line will show no power. If you now turn on the switch, then both black lines from the switch will be hot.

If you cannot reach into the box with a voltage probe, then you will need to turn off the power into the switch box. Make sure that all circuits into the box are dead. Now, remove the switch. With a continuity checker (a multimeter is another great tool to have around the home, and not at all expensive) verify that when the switch is off, there should be essentially infinite resistance between the brass screws on the switch (where the black wires connected to.) Now turn on the switch, and that resistance should go down to zero.

If the problem is in the switch, just buy a new one to replace the old.

If the switch tests ok, then the problem is with the line to the fixture, or at the fixture itself. With the voltage sensing probe, I would now check that the line at the light fixture shows power. If not, then it is a problem in the line, and an electrician will be helpful.

REMEMBER: ALWAYS TAKE EXTREME CARE AROUND ELECTRICITY.

share|improve this answer
    
Wear some insulating shoes, and avoid touching anything else (especially the plumbing and faucet) while doing this. If you aren't well grounded, a 120V shock is not a big deal. If you're standing barefoot in a puddle on the basement slab - OW! –  Jay Bazuzi Nov 11 '10 at 3:26

I had a similar experience and went as far as replacing a breaker. In the end it was a simple short that the old breaker wouldn't always trip over. I pulled the switch from the metal gang box and noticed a discoloration on one of the terminals. Some electrical tape over the terminal solved the problem.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.