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cniggeler · Nov 17, 2009, 06:22 PM

Hi,

We have a two-bulb, 24" fluorescent light in our laundry room. There are switches at either end of the room controlling the light. This light worked fine for the first year, then intermittently worked, and lately did not work at all. I have installed a new unit with new bulbs and everything is fine right now. However, when testing the voltage before reinstalling, I found that, with the wall switch off, there is a 36 volt reading between the black and white (hot and neutral) lines! If you shut off power at the breaker panel, it reads 0 volts (not surprisingly, I suppose).

I have read elsewhere that some bleed-through is normal for 3-way connections, but
a) Is 36 volts within the realm of "normal", and
b) could 36 volts be negatively impacting the ballast and/or the fluorescent bulbs, causing a shortened lifespan?

Finally, if there is a problem, would simply disconnecting a switch at one end be one way to fix it? Other suggestions appreciated, besides "Hire a qualified licensed electrician to fix your problem", which I already understand is a possible solution :)
Thanks!

ballengerb1 · Nov 17, 2009, 06:30 PM

Try testing between the black and a known ground other than the white, bet there is no voltage. Now test between the white and a known ground, got your voltage back didn't you. The white is a neutral for other fixtures or receptacles to.

cniggeler · Nov 17, 2009, 06:39 PM

Originally Posted by ballengerb1

Try testing between the black and a known ground other than the white, bet there is no voltage. Now test between the white and a known ground, got your voltage back didn't you. The white is a neutral for other fixtures or receptacles to.

Thanks, I will check it. There are other switches on this circuit (the overhead garage lights for one), so what you say is probably right even before testing.

But even assuming that's true, if my voltmeter reads 36 volts across the hot and neutral lines - the same hot and neutral lines being wired to the light fixture - isn't 36 volts going to the ballast and/or the fluorescent bulbs, and would this be a problem for either of those components? Thanks!

hkstroud · Nov 18, 2009, 05:04 AM

By any chance are the switches in the laundry room the lighted kind?

cniggeler · Nov 18, 2009, 06:55 AM

Originally Posted by hkstroud

By any chance are the switches in the laundry room the lighted kind?

No, they are just the "fat" rocker switches...

hkstroud · Nov 18, 2009, 04:32 PM

Suggest temporarily replacing rocker switches with regular toggle switches. Then check for voltage.

Lighted rocker switches (with out a neutral) work by allowing a small voltage to pass when in the off position. This voltage passes through the light bulb but is too small to make the bulb burn. If you remove the light bulb, the light in the switch does not glow. I'm not sure what effect the ballast in a fluorescent fixture would have on the light in a switch. It may cause the light in the switch not to burn.

Also I have just replace 10 or 12 switches with lighted rocker switches for some one. I found 3 that were faulty. The light in the switch did not burn. I guess what I am saying is that you could have lighted rocker switches that are not glowing. Either because they are defective or because of the effect of the ballast.

Lighted switched would account for the voltage as you described. Temporarily replacing with regular switches give you a hint.

Originally Posted by cniggeler

I have read elsewhere that some bleed-through is normal for 3-way connections,

No, that is not normal.