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sdppm February 15th 08 06:27 AM

Wiring Question Phanton Power when switch off
 
I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help

Bud-- February 15th 08 07:39 AM

Wiring Question Phanton Power when switch off
 
sdppm wrote:
I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help


A common question. You are probably measuring with a good digital meter.
You are seeing a "phantom voltage". There is capacitive coupling - as
between a hot wire and switched wire to and from the switch. This
produces a very small current, but produces a reading on a good high
resistance meter. A light bulb with pigtail leads will indicate if
voltage is actually present.

--
bud--

hobbes February 15th 08 11:22 AM

Wiring Question Phanton Power when switch off
 
On Feb 15, 1:27*am, sdppm wrote:
I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help


Hi,

It can depend on the dimmer. Some dimmers, like the Lutron Diva's have
a small glow lamp in the switch that glows when the switch is off.
They draw a small amount of power to glow. The current also goes
through the light bulb, but it is so low that the bulb does not light
up.

Warmest regards, Mike.

jJim McLaughlin February 15th 08 03:47 PM

Wiring Question Phanton Power when switch off
 
Blattus Slafaly £ ¥ 0/00 :) wrote:
sdppm wrote:

I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help



It's obvious you are leaking voltage through the switch.

No, it is not obvious.

Read the respomnse of poster "bud" in line above.

Ken February 15th 08 06:07 PM

Wiring Question Phanton Power when switch off
 
On Feb 15, 1:27*am, sdppm wrote:
I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help


I just want to make sure when you say off, you really mean off. On
most dimmers you either slide a switch or rotate a knob to brighten or
dim the lamp. And then there is a separate off, usually either a
distinct click at the dim end of the rotation, or else you have to
push in and click the switch to get "off". So you are really turning
the dimmer off as opposed to just setting it all the way to the dim
end of the range? You probably already know that but I wanted to ask
just to make sure rather than ASSume. The capacitive coupling with a
digital multimeter is probably the true cause.

Ken

Jeff Wisnia February 15th 08 07:36 PM

Wiring Question Phanton Power when switch off
 
sdppm wrote:
I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help



You didn't say whether those "some lights" were fitted with bulbs when
you made your measurements. If they were, and they are incandescent
bulbs, then what you wrote is highly unlikely.

I'm betting that the bulbs aren't in place and all the previous folks
who said your meter is just responding to a very weak microamp sized
capacitively coupled current are correct.

If the bulbs are in place, but they are not glowing dimly or at least
feeling warm to the touch after that 67 volts has been applied to them
for some time, then you need a get a pro in there to figure out what
kinds of electronic poltergeists have invaded your home.

HTH,

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.


EXT February 15th 08 08:32 PM

Wiring Question Phanton Power when switch off
 

"bud--" wrote in message
...
sdppm wrote:
I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help


A common question. You are probably measuring with a good digital meter.
You are seeing a "phantom voltage". There is capacitive coupling - as
between a hot wire and switched wire to and from the switch. This produces
a very small current, but produces a reading on a good high resistance
meter. A light bulb with pigtail leads will indicate if voltage is
actually present.

If it is phantom voltage being measured by a sensitive meter, you can often
prove it by measuring voltage between your left hand and your right hand.
They can be that sensitive.



sdppm February 15th 08 10:22 PM

Wiring Question Phanton Power when switch off
 
On Feb 15, 12:32*pm, "EXT" wrote:
"bud--" wrote in message

... sdppm wrote:
I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help


A common question. You are probably measuring with a good digital meter.
You are seeing a "phantom voltage". There is capacitive coupling - as
between a hot wire and switched wire to and from the switch. This produces
a very small current, but produces a reading on a good high resistance
meter. A light bulb with pigtail leads will indicate if voltage is
actually present.


If it is phantom voltage being measured by a sensitive meter, you can often
prove it by measuring voltage between your left hand and your right hand.
They can be that sensitive.


I had disconected the string of lights and thats when I show the 67
volts. I just hooked up the lights and measured the voltgage and it
was 32 volts when the lights were hooked up. Once again this is in the
off position not just the dimmer being set to low. The dimmer has a
rocker switch and a slider. These voltgages are coming with the rocker
switch in the off position

sdppm February 15th 08 10:24 PM

Wiring Question Phanton Power when switch off
 
On Feb 15, 12:32*pm, "EXT" wrote:
"bud--" wrote in message

... sdppm wrote:
I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help


A common question. You are probably measuring with a good digital meter.
You are seeing a "phantom voltage". There is capacitive coupling - as
between a hot wire and switched wire to and from the switch. This produces
a very small current, but produces a reading on a good high resistance
meter. A light bulb with pigtail leads will indicate if voltage is
actually present.


If it is phantom voltage being measured by a sensitive meter, you can often
prove it by measuring voltage between your left hand and your right hand.
They can be that sensitive.


You keep talking about the digital meters and there sensitivity. Would
I be better off with the old type meter and would the reading be more
true

Jeff Wisnia February 15th 08 11:31 PM

Wiring Question Phanton Power when switch off
 
sdppm wrote:

On Feb 15, 12:32 pm, "EXT" wrote:

"bud--" wrote in message

. .. sdppm wrote:

I wired up some lights with a dimmer switch. When I have the switch in
the off position I am still showing 67 volts. That is accross the
Netural( White) and the Load (Black) Wire. If I measure between the
netural and ground it is Zero and if I measure between the Load and
ground I get 67 volts. Where have I gone wrong. Thanks for the help


A common question. You are probably measuring with a good digital meter.
You are seeing a "phantom voltage". There is capacitive coupling - as
between a hot wire and switched wire to and from the switch. This produces
a very small current, but produces a reading on a good high resistance
meter. A light bulb with pigtail leads will indicate if voltage is
actually present.


If it is phantom voltage being measured by a sensitive meter, you can often
prove it by measuring voltage between your left hand and your right hand.
They can be that sensitive.


I trust that's not intended to mean that he uses his hand to hand
(through the chest) boody resistance to load the circuit he's measuring.
That could be problematic if there really happens to be a low impedance
source behind that voltage. G


You keep talking about the digital meters and there sensitivity. Would
I be better off with the old type meter and would the reading be more
true


A digital meter DOES give you a true reading of the voltage across it's
input leads. AAMOF it gives you a TRUER reading of the value of the
voltage source than a lower impedance meter will when the source
impedance is high.

It just won't put enough of a load across what it's connected to to
prevent miniscule currents flowing through capacitive coupling (or
sometimes leakage resistance) from creating a significant voltage across
the meter's very high input resistance. That's what's taken on the name
"phantom voltage".

As suggested above, connect a light bulb (A 6 watt incandescent night
lite will do fine.) in parallel with the meter's input leads and see
what it reads then in your particular situation.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.


jJim McLaughlin February 15th 08 11:38 PM

Wiring Question Phanton Power when switch off
 
sdppm wrote:

You keep talking about the digital meters and there sensitivity. Would
I be better off with the old type meter and would the reading be more
true


An analog meter would help, but what you really need is a lot cheaper.

Known good light bulb in a porcellin (sp?) or plastic socket and
pigtail leads.

If the bulb glows, you have a problem. If the blb doesn't glow,
no problem.

It won't glow.

HeyBub[_2_] February 16th 08 11:41 AM

Wiring Question Phanton Power when switch off
 
sdppm wrote:
If it is phantom voltage being measured by a sensitive meter, you
can often prove it by measuring voltage between your left hand and
your right hand. They can be that sensitive.


I had disconected the string of lights and thats when I show the 67
volts. I just hooked up the lights and measured the voltgage and it
was 32 volts when the lights were hooked up. Once again this is in the
off position not just the dimmer being set to low. The dimmer has a
rocker switch and a slider. These voltgages are coming with the rocker
switch in the off position


IGNORE THE METER READING!

The meter is lying.

What you see is a phantom.

Working voltage does not exist.

Forget about it.

If the meter doesn't read 120 then the actual voltage is zero.




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