Question for electrical gurus

[Louis Brandt]

Hello,

I have a 2 bulb 40 watt fluorescent light fixture at the ceiling in my garage. This morning, both lights stopped working. Since the bulbs had been in for quite a while, I replaced them both, but the new ones don’t work either.

I then checked the wall switch, which is a standard two-way switch. When I put my voltage tester on it, I get NO reading when the switch is in the ON position, but with the switch in the OFF position, I get a normal 110 volt reading!

The switch is not installed upside down, since it has always worked when the switch is turned to the on position.

Question: Do I have a short circuit due to a problem with the fluorescent fixture, or do I have a defective switch or both or what? And why do I get a meter reading when the switch is OFF?

Thanks,
Louis

[Ken Fitzgerald]

Louis...What you are reading is normal. When the switch is off, the full voltage is measured across the open contacts of the switch. When the switch is on, there is a short between the contacts of the switch and thus no potential difference and you don't measure any voltage. That is normal.

It sounds like you have lost a ballast in the fixture.

[Mike Mathieu]

Hi Louis
Even with the switch in the off position you will have 110 volts on one screw of the switch. You need to check the other side of the switch from the other screw to ground to see if the switch is bad. If the switch is on and you do not have 110 volts on both screws to ground than the switch is bad.If you have 110 volts on both screws than you have a bad wire from the switch to the fixture or the ballast in the fixture is bad.

[Anthony Whitesell]

Like Ken said, that's normal. The measurement you're taking across the switch is from from Hot to Open-Hot, and not from Hot-to-Neutral. The black wire on the meter should be placed on a neutral wire, not on the other side of a switched hot connection. When the switch closes, you're essentially touching the probes together. On the bright side, you've verified the switch is good.

Chances are the fixture (ballast) is toast. How old is the fixture? Where did you get it from? the borg? My borg fixtures only last 3-4 years and I'm in the process of replacing them one-by-one again for the second time. I'm opting for the Wal-mart specials this time to see if they last longer.

[Louis Brandt]

Thanks guys! I think that I'll get a whole new fixture, since I've been wanting a four bulb fixture to replace the two bulb one.
Thanks again,
Louis

[Gary Radice]

Thanks guys! I think that I'll get a whole new fixture, since I've been wanting a four bulb fixture to replace the two bulb one.
Thanks again,
Louis

And while you are at it, consider getting a fixture that uses T8 bulbs rather than T12 (if it isn't a T8 already). Better light for less electricity.

[Chris Padilla]

And while you are at it, consider getting a fixture that uses T8 bulbs rather than T12 (if it isn't a T8 already). Better light for less electricity.

Also quieter and will fire up right away even in very cold temperatures.