When I was replacing the switch for my disposal, my paranoia led me
test all the wires before grabbing the switch and I'm glad I did,
because the hot still had exactly 40V on it.

After playing the circuit breaker game for 15 minutes, I came to find
that the voltage only disappeared after I turned off the dishwasher
circuit. I thought the disposal was supposed to be wired on it own
circuit.

Can anyone explain this? I can't remember exactly how it was wired,
but one of the cables was 3-wire.

"bakerguy" wrote in message
oups.com...
When I was replacing the switch for my disposal, my paranoia led me
test all the wires before grabbing the switch and I'm glad I did,
because the hot still had exactly 40V on it.

After playing the circuit breaker game for 15 minutes, I came to find
that the voltage only disappeared after I turned off the dishwasher
circuit. I thought the disposal was supposed to be wired on it own
circuit.

Can anyone explain this? I can't remember exactly how it was wired,
but one of the cables was 3-wire.

It is common, perhaps even normal, to put the dishwasher and disposal on the
same circuit.

However, if you turn the breaker off, the hot should have no voltage under
any circumstances. I suspect it was a ghost reading of no consequence.

"toller" wrote in message
...

"bakerguy" wrote in message
oups.com...
When I was replacing the switch for my disposal, my paranoia led me
test all the wires before grabbing the switch and I'm glad I did,
because the hot still had exactly 40V on it.

After playing the circuit breaker game for 15 minutes, I came to find
that the voltage only disappeared after I turned off the dishwasher
circuit. I thought the disposal was supposed to be wired on it own
circuit.

Can anyone explain this? I can't remember exactly how it was wired,
but one of the cables was 3-wire.

It is common, perhaps even normal, to put the dishwasher and disposal on
the same circuit.

However, if you turn the breaker off, the hot should have no voltage under
any circumstances. I suspect it was a ghost reading of no consequence.

induced voltage. it has no current available so isn't usually a risk.

bakerguy wrote:
When I was replacing the switch for my disposal, my paranoia led me
test all the wires before grabbing the switch and I'm glad I did,
because the hot still had exactly 40V on it.

After playing the circuit breaker game for 15 minutes, I came to find
that the voltage only disappeared after I turned off the dishwasher
circuit. I thought the disposal was supposed to be wired on it own
circuit.

Can anyone explain this? I can't remember exactly how it was wired,
but one of the cables was 3-wire.

You were measuring that with a nice digital meter. They have such high
internal resistance that they will read induced current from a hot wire
running near the one you are measuring. You need to put a little load on it
and it will drop to zero. You could also just get an old analog meter and
it will not budge.

If that line was live, it would not show 40V it would be more like 120V.

--
Joseph Meehan

26 + 6 = 1 It's Irish Math

This is a multiwire circuit with a shared neutral. You might have a loose
neutral in there or you may have just been seeing the phantom voltage that you
get with digital meters. If you can get these breakers next to each other it is
a good idea to tie the handles together so you won't have a surprise next time.

What's the best way to apply a load to a circuit with only a switch
accessible?

bakerguy wrote:
What's the best way to apply a load to a circuit with only a switch
accessible?

That question makes me worry a little. You need to be careful fooling
with this stuff. While almost all the time this comes up it is as I
suggested, it is also possible you have a floating neutral and messing with
that could be dangerous to your health if you don't know what you are going
or are not careful.

You can load the circuit by turning on any device on that circuit, like
a light or you can use say a test light across the lines. The test light
should drop the reading to zero or very close to it and normally will not
light the test light.

--
Joseph Meehan

26 + 6 = 1 It's Irish Math

Dishwaser & disposal together isn't unusual.
The 40V is called a "phantom" voltage. It's due to adjacent
wiring inducing magnetic energy into the ones you are measuring.
Your meter has an extremely high input impedance (Resistance), so
it's able to measure that very weak megnrtic field's coltage
creation. Put ANYTHING conductive across the two wires, and the
voltage will drop to the expected 0Vac. As long as the voltage
us under 100Vac, A light bulb, clock, anything that draws even a
tiny amount of current will drop that voltage to zero because it
isn't there in the sense of being able to supply anything more
than a couple of micro-amps of current.
On the ckts that power my flour. lights, I'll see 90Vac when
the lights are on: there must be a line runs along the fixture
and past the ballasts in the ceiling.
DON'T DO THIS because a mistake will ruin your meter, but ...
if you shorted the two wires through your current (Amps) scale,
you would measure zero amps; the needle wouldn't even move.
Still ALWAYS treat wiring as though it were live, even when you
KNOW it can't be. Good techniques saves lives.

So, it's perfectly normal and even expected with most
multimeters.

Pop


bakerguy wrote:
When I was replacing the switch for my disposal, my paranoia
led me
test all the wires before grabbing the switch and I'm glad I
did,
because the hot still had exactly 40V on it.

After playing the circuit breaker game for 15 minutes, I came
to find
that the voltage only disappeared after I turned off the
dishwasher
circuit. I thought the disposal was supposed to be wired on
it own
circuit.

Can anyone explain this? I can't remember exactly how it was
wired,
but one of the cables was 3-wire.

--
--
One should not be so p-h-i-l-o-p-o-L-e-m-i-c
lest they be seen as disputatious.