Light Fixture Will Not Wo

[barry martin]

Ernie:

E&> I have a strange problem here. Light fixture suddenly does not work. All E&> bulbs OK, of course. I assumed it was a bad switch, which I replaced with E&> no change. E&> E&> I checked line voltage at the switch........it is fine, 122V. However, at E&> the fixture, there are only 75V! Not enough voltage to operate the fixture E&> bulbs. Why am I losing so many volts, and how to correct?

There's an open somewhere. I'm assuming the fixture in question uses an incandescent bulb rather than fluorescent and the replaced switch was in the fixture. This means the open is probably somewhere between the plug and the switch, more than likely at th plug itself. Possibly failed because the plug was bent at a right angle by furniture.

Note: it may be cheaper to buy an extension cord and cut the socket end off than to buy a length of wire with plug.

- ¯ barry.martinþATþthesafebbs.zeppole.com ®

• Definition: Hydrophobia - fear of fire hydrants.

[Tim or Marty Shephard]

What kind of meter are you using?

75v between which 2 color wires? I'll bet 75v will light most any incandescent bulb (like a dimmer does). I'll also bet you have a fairly good meter that is showing a stray (low load) voltage.

You just gotta chase the full voltage through each box or connection. Get a test light that you can put a 75 watt bulb in, and clip it down the wiring until it fails.

Tim S.

[Jeff Wisnia]

I'm interested in your reasoning there Barry.

If the OP said he had 122V "at the switch", and you assumed that what he called a "light fixture" was just a lamp, with the replaced switch in it, then why would you blame the cord, which is *ahead* of the switch?

I'll bet the "light fixture" is on a ceiling or wall, and the switch is a wall switch. He's probably getting that 75 volt reading because he's using a sensitive digital meter, the return (white) wire from the fixture has a break in it somewhere, and he's seeing that 75 volts fed through the capacitive reactance of the wiring.

Jeff

[Ernie D]

Yes, I am talking about a wall mounted dimmer switch which controls a ceiling mounted light multi-light fixture.

When I check voltage coming into switch, it is 122V. When I turn the dimmer switch off and check voltage at wiring into fixture, I get 0 volts. When I turn the switch on, it reads initially at 70V, then quickly lowers to a reading of 50V.

Of course, I am checking fixture input V with the dimmer switch at multiple positions, but makes no difference.

Does all this just sound like an open circuit in the white? That would be a real problem, since allthis wiring is behind finished walls.

Thanks,

[Jeff Wisnia]

Sorry to have to tell you it still does. If you want to make one more test, bypass that dimmer switch completely by removing the two black wires from it and temporarily connecting them together.

If you still get the same "funny" readings at the fixture, try measuring from the black wire there to a ground (the bare or green wire). If you see full line voltageto ground, then it's almost certainly an "open" in the white wire.

If you measure full line voltage between the black and white wires at the fixture with the dimmer switch bypassed (and the bulbs should light too) then something was/is wrong with both the old and new dimmer switches or how you connected the new one.

Wires in walls don't often break by themselves. Unless severed by physical damage, a break is most likely due to a poorly made splice in some junction box which has gotten corroded or disconnected.

Good luck,

Jeff