"Terry" wrote in message
...
On 28 Feb 2007 18:07:40 -0800, "
wrote:

I have what seems to be something wrong with a 3 way switch on the
light at the top of my stairs. This light can be turned off/on from
the bottom of the stair as well as from the top.

I was replacing the fixture at the top of the stair and turned the
power off at the switch thinking that I would be safe to replace the
fixture. After removing the screws holding the fixture to the ceiling
I checked the light with my greenlee gt-11 voltage detector and was
surprised to hear the unit ringing. I broke out the DVM and sure
enough 92 volts between the white and black wires to the fixture.

Turning on the light the voltage goes to 120vac, off back to 92vac.

So something seems very wrong, I went to the panel and turned off the
breaker and changed out the fixture. I am now glad I was lazy and did
it the wrong way first.

I don't understand why the incandecent bulb did not light at 92
volts. I have replaced the bulb with a CF as that is what we are
doing throughtout the house.

About the house:
1957 cape 2 wire hot/neutral with no ground for all parts of the
house. Any new work has been done with romex in proper gauges for
circuits.
5 years ago we had the 100Amp fuse panel replaced with a 200 amp
breaker panel.

Any common problems that might cause this?
Am I using electricity even though the light is off?

Thanks!
e

This could happen if you have the neutral switched instead of the hot.
The 120 - 90 drop could be because you are measuring with the lamps in
the circuit. If you take the lamps out and you do have a switched
neutral then tester would then read 0.


The cold resistance of a lamp is so low compaired to the meter it should
still read within a couple of tenths of a volt of the line voltage. This
may be differant with the new compact flouresent lamps as I have not checked
any of them.

All that is being measured is some induced voltage or possiably some very
low leakage current from the switches. If it is leakage current, it would
still be so low as not to be any danger. It only takes one or two miliamps
to be felt by most on the skin. Going by the voltage drop in the on/off
states it would be in the microamp range of current in the off state of the
switches.