Ghost Voltage

--------------------------------------------------------------------------------

HELP! I just can't figure this out. I installed low voltage lighting under my kitchen cabinets with 3-way switches. They always performed rather oddly. I would turn them on and they would light after a brief delay. I don't know why, maybe something with the transformer.
Well, the transformer finally failed and I bought a replacement. I checked my wiring to try and find out why I was getting a delay and found something quite bizarre. I isolated the 3-wire and ran voltage on the black leg only. Well, my digital meter shows 57 volts on the red leg. Yes, the red leg is attached to nothing. I suspected the hot legs were touching each other and bleeding voltage through the insulation. I rang them out and there is no bleed from red to black or vice-versa. There is no short to ground. The ghost voltage also appears when I energize the opposite leg. Is this some kind of EMF? Is it safe to assume that the transformer remains energized at a low voltage even when turned off? It can't be anything with using 3-way switching with a transformer because I get the ghost voltage without the transformer being connected. The 3 wire runs behind the stove. Maybe the heat from the stove is melting the insulation enough to cause bleed, but the red and black legs ring out ok. Does this make sense to anyone? Please enlighten me, I am defeated.

Water-Lou wrote:
Ghost Voltage

--------------------------------------------------------------------------------

HELP! I just can't figure this out. I installed low voltage lighting
under my kitchen cabinets with 3-way switches. They always performed
rather oddly. I would turn them on and they would light after a brief
delay. I don't know why, maybe something with the transformer.
Well, the transformer finally failed and I bought a replacement. I
checked my wiring to try and find out why I was getting a delay and
found something quite bizarre. I isolated the 3-wire and ran voltage on
the black leg only. Well, my digital meter shows 57 volts on the red
leg. Yes, the red leg is attached to nothing. I suspected the hot legs
were touching each other and bleeding voltage through the insulation. I
rang them out and there is no bleed from red to black or vice-versa.
There is no short to ground. The ghost voltage also appears when I
energize the opposite leg. Is this some kind of EMF? Is it safe to
assume that the transformer remains energized at a low voltage even
when turned off? It can't be anything with using 3-way switching with a
transformer because I get the ghost voltage without the transformer
being connected. The 3 wire runs behind the stove. Maybe the heat from
the stove is melting the insulation enough to cause bleed, but the red
and black legs ring out ok. Does this make sense to anyone? Please
enlighten me, I am defeated.




Hi,
DVM is too sensitive due to high input impedance. Use plain old analog
meter not to get confused.

Water-Lou wrote:
Ghost Voltage


--------------------------------------------------------------------------
------

HELP! I just can't figure this out. I installed low voltage lighting
under my kitchen cabinets with 3-way switches. They always performed
rather oddly. I would turn them on and they would light after a brief
delay. I don't know why, maybe something with the transformer.
Well, the transformer finally failed and I bought a replacement. I
checked my wiring to try and find out why I was getting a delay and
found something quite bizarre. I isolated the 3-wire and ran voltage on
the black leg only. Well, my digital meter shows 57 volts on the red
leg. Yes, the red leg is attached to nothing.

Buy one of these:

http://cgi.ebay.com/KLEIN-Wiggy-mode...QQcmdZViewItem
Read this:
http://en.wikipedia.org/wiki/Solenoid_voltmeter

Al

Water-Lou wrote:
Ghost Voltage

...
Well, my digital meter shows 57 volts
....
Is this some kind of EMF?

Yes.

Get a old analog volt meter and you will not have the problem.


--
Joseph Meehan

Dia duit

or load with say a 40 watt lamp while measuring voltage.

digital meters are wonderful but respond to nothing..

Water-Lou wrote:
Ghost Voltage

--------------------------------------------------------------------------------

HELP! I just can't figure this out. I
Well, my digital meter shows 57 volts on the red
leg. Yes, the red leg is attached to nothing. I suspected the hot legs
were touching each other and bleeding voltage through the insulation.............etc.

This question has come up often; usually posed by those with only
basic (or no) electrical training?
..
Suggested (basic) explanantion.
Home electrical supply is AC (Alternating Current).
All conducting objects, such as metal wires, have capacitance to other
objects.
The two wires in a cable have capacitance to each other (and possibly
to other wiring even if some distance away) so at AC (even at the low
frequency of 60 hertz, or 50 if you are in Europe etc.). there can be
capacitive 'coupling' between an unconnected wire and another.
Even though that coupling is very slight the input to a digital meter
is so sensitive and of high impedance that the meter will 'see' voltage
via the coupling effect. The coupled voltage is normally meaningless.
It is better as has been suggested to use a test lamp or a 'Non digital
meter'.
Digital meters have their uses e.g. to test very sensitive circuits
within electronic equipment where a test lamp or anaolg meter would
interfere or mask equipment operation. This is not the case when you
are dealing with domestic and commercial low impedance heating and
lighting circuits.
Any help?

If I understand correctly, you tried to hook the cabinet lighting
transformer into same circuit as kitchen main lighting, right? And
you have multiple switches there? And the box you tapped into houses a
3-pole switch fed with a 3-conductor cable?? It is not a 220V circuit
- so did you wonder why there would be a 3-conductor there? It is more
expensive, so an electrician will not use it unless needed.

A bit of trivia: hook a meter in series with a 40-60 watt lightbulb and
check voltage on the meter. Chances are, you'll get around 50-60
volts. Most meters are ranged to 400mA and a 60W bulb draws about
500mA. In series, they will split voltage about in half.

I had a similar problem long ago when wanting to install a new outlet
and I found a very convenient cable running in the wall right where I
wanted the outlet. Tapping into cable revealed 3 wires. Not giving
it much thought, I wired outlet between black and white, only to get an
outlet that would not work at all or have VERY low power at - guess what
- about 50 volts. Was dumbfounded until I traced all wires and found
out I tapped into a traveler running between top and bottom staircase
switches.

Really, I also had theories about capacitance, EMF, ESP, stray
currents, and other exotic stuff, while in truth I simply had it wired
in a series with a lightbulb. Trace your wires. Looks like the box
you hooked into is final on a power-through-fixture chain.




--
scorrpio

"scorrpio" wrote in message
m...

A bit of trivia: hook a meter in series with a 40-60 watt lightbulb and
check voltage on the meter. Chances are, you'll get around 50-60
volts. Most meters are ranged to 400mA and a 60W bulb draws about
500mA. In series, they will split voltage about in half.

No general purpose meters I know draws 400mA when testing voltages. Except
maybe solenoid tester. They draw more current but I have no idea how much.
But solenoid tester can't give you accurate voltage reading at 50V.

On Mon, 14 Aug 2006 16:39:48 GMT, "peter" wrote:

"scorrpio" wrote in message
om...

A bit of trivia: hook a meter in series with a 40-60 watt lightbulb and
check voltage on the meter. Chances are, you'll get around 50-60
volts. Most meters are ranged to 400mA and a 60W bulb draws about
500mA. In series, they will split voltage about in half.

No general purpose meters I know draws 400mA when testing voltages. Except
maybe solenoid tester. They draw more current but I have no idea how much.
But solenoid tester can't give you accurate voltage reading at 50V.


I tried that (measuring voltage in series with 60W bulb). The DMM
showed 120V (same as supply).

The 400mA may be the limit for a current range on a 3 3/4-digit DMM.
That would have nothing to do with the load when measuring voltage. I
guess someone knows very little about electricity.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Democracy is two wolves and a lamb voting on what
to have for lunch. Liberty is a well armed lamb
contesting the vote." - Benjamin Franklin

Mark Lloyd wrote:
On Mon, 14 Aug 2006 16:39:48 GMT, "peter" wrote:

"scorrpio" wrote in
message m...

A bit of trivia: hook a meter in series with a 40-60 watt lightbulb
and check voltage on the meter. Chances are, you'll get around
50-60 volts. Most meters are ranged to 400mA and a 60W bulb draws
about 500mA. In series, they will split voltage about in half.

No general purpose meters I know draws 400mA when testing voltages.
Except maybe solenoid tester. They draw more current but I have no
idea how much. But solenoid tester can't give you accurate voltage
reading at 50V.


I tried that (measuring voltage in series with 60W bulb). The DMM
showed 120V (same as supply).

The 400mA may be the limit for a current range on a 3 3/4-digit DMM.
That would have nothing to do with the load when measuring voltage. I
guess someone knows very little about electricity.

Try running that lamp in parallel. Series will not make much
difference.

--
Joseph Meehan

Dia duit

On Mon, 14 Aug 2006 21:27:17 GMT, "Joseph Meehan"
wrote:

Mark Lloyd wrote:
On Mon, 14 Aug 2006 16:39:48 GMT, "peter" wrote:

"scorrpio" wrote in
message m...

A bit of trivia: hook a meter in series with a 40-60 watt lightbulb
and check voltage on the meter. Chances are, you'll get around
50-60 volts. Most meters are ranged to 400mA and a 60W bulb draws
about 500mA. In series, they will split voltage about in half.

No general purpose meters I know draws 400mA when testing voltages.
Except maybe solenoid tester. They draw more current but I have no
idea how much. But solenoid tester can't give you accurate voltage
reading at 50V.


I tried that (measuring voltage in series with 60W bulb). The DMM
showed 120V (same as supply).

The 400mA may be the limit for a current range on a 3 3/4-digit DMM.
That would have nothing to do with the load when measuring voltage. I
guess someone knows very little about electricity.

Try running that lamp in parallel. Series will not make much
difference.

At least with parallel, the light will work.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Democracy is two wolves and a lamb voting on what
to have for lunch. Liberty is a well armed lamb
contesting the vote." - Benjamin Franklin

1st off and don't take this wrong, do you understand how 3-way
switches work? Most folks don't and you mention below that they
always performed rather oddly. Insofar as the transformer, that
should merely be 110v in across the primary (*switchleg* and 110
system neutral to power it) and then the secondary providing power to
the low voltage lighting which is all effectively switched by your
110v 3 way switch system..

On Sun, 13 Aug 2006 04:13:11 +0100, Water-Lou
wrote:


Ghost Voltage

--------------------------------------------------------------------------------

HELP! I just can't figure this out. I installed low voltage lighting
under my kitchen cabinets with 3-way switches. They always performed
rather oddly. I would turn them on and they would light after a brief
delay. I don't know why, maybe something with the transformer.
Well, the transformer finally failed and I bought a replacement. I
checked my wiring to try and find out why I was getting a delay and
found something quite bizarre. I isolated the 3-wire and ran voltage on
the black leg only. Well, my digital meter shows 57 volts on the red
leg. Yes, the red leg is attached to nothing. I suspected the hot legs
were touching each other and bleeding voltage through the insulation. I
rang them out and there is no bleed from red to black or vice-versa.
There is no short to ground. The ghost voltage also appears when I
energize the opposite leg. Is this some kind of EMF? Is it safe to
assume that the transformer remains energized at a low voltage even
when turned off? It can't be anything with using 3-way switching with a
transformer because I get the ghost voltage without the transformer
being connected. The 3 wire runs behind the stove. Maybe the heat from
the stove is melting the insulation enough to cause bleed, but the red
and black legs ring out ok. Does this make sense to anyone? Please
enlighten me, I am defeated.

Hello Terry,

Thank you very much for responding to my query.
Electrical training? YES.
I just remembered a very important point that I forgot on my original post and I completely apologize. I'm just too frustrated.
I took a seperate piece of three wire to a separate source altogether and performed the same test and found NO voltage on the red leg when energizing the black leg to 110v using the same fluke meter. Go back home; go to the same set up; use the 3 wire in the wall; ghost voltage on the red leg.

Hello Tony,

Thank you for taking the time to try to help me, I appreciate it very much.
I just remembered a very important point that I forgot on my original post and I completely apologize. I'm just too frustrated.
I took a separate piece of three wire to a separate source altogether and performed the same test and found NO voltage on the red leg when energizing the black leg to 110v using the same fluke meter. Go back home; go to the same set up; use the 3 wire in the wall; ghost voltage on the red leg.
I do have a Greenlee analog, will try!

Hello Big Al,

Thank you for taking the time to try to help me, I appreciate it very much.
I just remembered a very important point that I forgot on my original post and I completely apologize. I'm just too frustrated.
I took a separate piece of three wire to a separate source altogether and performed the same test and found NO voltage on the red leg when energizing the black leg to 110v using the same fluke meter. Go back home; go to the same set up; use the 3 wire in the wall; ghost voltage on the red leg.
I do have a Greenlee analog, will try!

Hello Joe,

Thank you for taking the time to try to help me, I appreciate it very much.
I just remembered a very important point that I forgot on my original post and I completely apologize. I'm just too frustrated.
I took a separate piece of three wire to a separate source altogether and performed the same test and found NO voltage on the red leg when energizing the black leg to 110v using the same fluke meter. Go back home; go to the same set up; use the 3 wire in the wall; ghost voltage on the red leg.
I do have a Greenlee analog, will try!

Hello Scorrpio,

Thank you for taking the time to try to help me, I appreciate it very much.
I wired the kitchen myself. There is no exotic wiring here. It's 3 wire because it is 3 way. No 220v here. It is dedicated to the cabinet lighting. All tests were performed isolating the 3 wire from ANYTHING else.
I just remembered a very important point that I forgot on my original post and I completely apologize. I'm just too frustrated.
I took a separate piece of three wire to a separate source altogether and performed the same test and found NO voltage on the red leg when energizing the black leg to 110v using the same fluke meter. Go back home; go to the same set up; use the 3 wire in the wall; ghost voltage on the red leg.

Hello Cover,

Thank you for taking the time to try to help me, I appreciate it very much.