Hi,

I'm currently helping my girlfriend figure out what a switch in a spare
bedroom actually goes to, however I ran into a problem with voltages on
the switch.

Here's the setup:

1 - 12-2+G
1 - 12-3+G going into the box.

Black from 12-2 goes to top screw poll of switch
Black from 12-3 goes to top push fit poll of switch
Red from 12-3 goes to bottom poll of switch
Whites are bonded
Grounds are bonded, pigtail not connected to anything

From what little electrical I know, this seems like a 3 way switch
setup, however I have no idea where it could possibly go to. Also, if
it is a 3 way setup, I know the switch isn't a 3 way switch, so there's
no real way this should work anyway. I know it doesn't go to any of
the outlets in the room as they get a full 120V on top and bottom at
all times.

My concern is the voltages I'm reading on the switch.

With the switch in the off position I get:

H to N: 84.8V
H to G: 121.9V
N to G: 27.9V

With the switch in the on position:

H to N: 0V
H to G: 121.9V
N to G: 121.9V

I'm confused. Anyone out there know what could possibly be going on
with this switch?

Thanks.

Max wrote:

Hi,

I'm currently helping my girlfriend figure out what a switch in a spare
bedroom actually goes to, however I ran into a problem with voltages on
the switch.

Here's the setup:

1 - 12-2+G
1 - 12-3+G going into the box.

Black from 12-2 goes to top screw poll of switch
Black from 12-3 goes to top push fit poll of switch
Red from 12-3 goes to bottom poll of switch
Whites are bonded
Grounds are bonded, pigtail not connected to anything

From what little electrical I know, this seems like a 3 way switch
setup, however I have no idea where it could possibly go to. Also, if
it is a 3 way setup, I know the switch isn't a 3 way switch, so there's
no real way this should work anyway. I know it doesn't go to any of
the outlets in the room as they get a full 120V on top and bottom at
all times.

My concern is the voltages I'm reading on the switch.

With the switch in the off position I get:

H to N: 84.8V
H to G: 121.9V
N to G: 27.9V

With the switch in the on position:

H to N: 0V
H to G: 121.9V
N to G: 121.9V

I'm confused. Anyone out there know what could possibly be going on
with this switch?

Thanks.

It doesn't sound like you have a three way switch, it sounds like a
regular single pole switch. The top screw terminal and the top back wire
port are electrically the same, someone was just too lazy to pigtail and
connect both wires to the screw terminal.

Seems most likely that it is feeding a split duplex outlet with one half
switched and the other constant. The 12/2 would be the incoming power
feed and the 12/3 would be the feed out the the outlet with the red the
switched leg and the black the constant leg.

The voltage readings are indeed odd and likely represent a serious
ground fault or wiring error at a location other than the switch box.
The wiring in the switch box sounds reasonable although the ground
pigtail you mention should go to a ground screw on the switch or in the
box if it's metal. Not likely the source of the strange voltage readings
though.

I'd start by disconnecting power, disconnecting the wiring in the switch
box and then powering up and checking the lines separately. You should
find the 12/2 to be the incoming power with voltages as you would
expect, 120V nominal H-N and H-G and 0V N-G. I would expect everything
on the 12/3 side to read 0V with it disconnected from anything in the
switch box. Any readings that don't match this will give you a direction
to search in.

As always be careful and don't get fried.

Pete C.

"Max" wrote in message
oups.com...
Hi,

I'm currently helping my girlfriend figure out what a switch in a spare
bedroom actually goes to, however I ran into a problem with voltages on
the switch.

Here's the setup:

1 - 12-2+G
1 - 12-3+G going into the box.

Black from 12-2 goes to top screw poll of switch
Black from 12-3 goes to top push fit poll of switch
Red from 12-3 goes to bottom poll of switch
Whites are bonded
Grounds are bonded, pigtail not connected to anything

From what little electrical I know, this seems like a 3 way switch
setup, however I have no idea where it could possibly go to. Also, if
it is a 3 way setup, I know the switch isn't a 3 way switch, so there's
no real way this should work anyway. I know it doesn't go to any of
the outlets in the room as they get a full 120V on top and bottom at
all times.

My concern is the voltages I'm reading on the switch.

With the switch in the off position I get:

H to N: 84.8V
H to G: 121.9V
N to G: 27.9V

With the switch in the on position:

H to N: 0V
H to G: 121.9V
N to G: 121.9V

I'm confused. Anyone out there know what could possibly be going on
with this switch?

Thanks.


It is not a 3 way switch set. The two blacks are joined together at the
switch instead of being spliced together with a wire connector. Usually the
black is feeding through on the 3 wire and the red is the switch leg. If
you disconnected all of the wires you may find that the 2 wire is the feed
and you should have approximately 120 volts between the white and black. See
what doesn't work after you disconnect the black wires. There could be a
ceiling fixture box that has been covered over. It is possible that there
was a switched receptacle at one time and the previous owner changed it to
be on all of the time. Open each outlet and look for the red wire.

How old is the house?

Stop using a voltmeter and get a pigtail socket and a light bulb and check
every outlet top and bottom again.

Max wrote:
Hi,

I'm currently helping my girlfriend figure out what a switch in a
spare bedroom actually goes to, however I ran into a problem with
voltages on the switch.

Here's the setup:

1 - 12-2+G
1 - 12-3+G going into the box.

Black from 12-2 goes to top screw poll of switch
Black from 12-3 goes to top push fit poll of switch
Red from 12-3 goes to bottom poll of switch
Whites are bonded
Grounds are bonded, pigtail not connected to anything

From what little electrical I know, this seems like a 3 way switch
setup, however I have no idea where it could possibly go to. Also, if
it is a 3 way setup, I know the switch isn't a 3 way switch, so
there's no real way this should work anyway. I know it doesn't go to
any of the outlets in the room as they get a full 120V on top and
bottom at all times.

My concern is the voltages I'm reading on the switch.

With the switch in the off position I get:

H to N: 84.8V
H to G: 121.9V
N to G: 27.9V

With the switch in the on position:

H to N: 0V
H to G: 121.9V
N to G: 121.9V

I'm confused. Anyone out there know what could possibly be going on
with this switch?

Thanks.

I suspect you may be getting a false voltage reading. Modern meters are
too sensitive. Put a high resistance load across those circuits and likely
your odd voltages 27.9 & 84.8 will drop to zero.

--
Joseph Meehan

Dia duit

"Pete C." wrote in message :

SNIPS


It doesn't sound like you have a three way switch, it sounds like a
regular single pole switch. The top screw terminal and the top back wire
port are electrically the same, someone was just too lazy to pigtail and
connect both wires to the screw terminal.

Seems most likely that it is feeding a split duplex outlet with one half
switched and the other constant. The 12/2 would be the incoming power
feed and the 12/3 would be the feed out the the outlet with the red the
switched leg and the black the constant leg.

The voltage readings are indeed odd and likely represent a serious
ground fault or wiring error at a location other than the switch box.
The wiring in the switch box sounds reasonable although the ground
pigtail you mention should go to a ground screw on the switch or in the
box if it's metal. Not likely the source of the strange voltage readings
though.

I'd start by disconnecting power, disconnecting the wiring in the switch
box and then powering up and checking the lines separately. You should
find the 12/2 to be the incoming power with voltages as you would
expect, 120V nominal H-N and H-G and 0V N-G. I would expect everything
on the 12/3 side to read 0V with it disconnected from anything in the
switch box. Any readings that don't match this will give you a direction
to search in.

As always be careful and don't get fried.

Pete C.

Good cogent analysis.

--
Jim McLaughlin

Reply address is deliberately munged.
If you really need to reply directly, try:
jimdotmclaughlinatcomcastdotcom

And you know it is a dotnet not a dotcom
address.

Could have been a 3 way set up. Or the 12-3 goes to a plug. The hot side
of the plug is clipped so one plug is switched (hot fed with the red lead)
and other plug is always on (fed with the black). So you could plug and
lamp in one and a clock radio in the other.

Check both top and bottom of each plug to see if this is the case.


"Max" wrote in message
oups.com...
Hi,

I'm currently helping my girlfriend figure out what a switch in a spare
bedroom actually goes to, however I ran into a problem with voltages on
the switch.

Here's the setup:

1 - 12-2+G
1 - 12-3+G going into the box.

Black from 12-2 goes to top screw poll of switch
Black from 12-3 goes to top push fit poll of switch
Red from 12-3 goes to bottom poll of switch
Whites are bonded
Grounds are bonded, pigtail not connected to anything

From what little electrical I know, this seems like a 3 way switch
setup, however I have no idea where it could possibly go to. Also, if
it is a 3 way setup, I know the switch isn't a 3 way switch, so there's
no real way this should work anyway. I know it doesn't go to any of
the outlets in the room as they get a full 120V on top and bottom at
all times.

My concern is the voltages I'm reading on the switch.

With the switch in the off position I get:

H to N: 84.8V
H to G: 121.9V
N to G: 27.9V

With the switch in the on position:

H to N: 0V
H to G: 121.9V
N to G: 121.9V

I'm confused. Anyone out there know what could possibly be going on
with this switch?

Thanks.

See ==== below

"Max" wrote in message
oups.com...
Hi,

I'm currently helping my girlfriend figure out what a switch in
a spare
bedroom actually goes to, however I ran into a problem with
voltages on
the switch.

Here's the setup:

1 - 12-2+G
1 - 12-3+G going into the box.

Black from 12-2 goes to top screw poll of switch
Black from 12-3 goes to top push fit poll of switch
==== Typically these are connected together inside the switch.
It was probably used as a splice.
Red from 12-3 goes to bottom poll of switch
==== Makes sense; this would likely be the "hot" lead to
whatever it is/was meant to control.
Whites are bonded
==== Normal.
Grounds are bonded, pigtail not connected to anything
==== Not sure what you mean; probably they aren't using the
earthing connection? Probably of no import.

From what little electrical I know, this seems like a 3 way
switch
setup, however I have no idea where it could possibly go to.
Also, if
it is a 3 way setup, I know the switch isn't a 3 way switch, so
there's
no real way this should work anyway. I know it doesn't go to
any of
the outlets in the room as they get a full 120V on top and
bottom at
all times.
==== Try disconnecting either the black and/or red and see if
anything changes. Be sure you open the breaker before going in
there, though.

My concern is the voltages I'm reading on the switch.
==== What you're seeing is typical of what they call phantom
voltages. Most meters have a high enough input impedance that
they read voltages induced into the wiring from nearby wires, out
of the air, whatever. It's not unusual and almost always not a
problem.
If you open the breaker to those wires you'll probably still
see phantom voltages even though the breaker is open. Same for
any other outlets/switches.

With the switch in the off position I get:

H to N: 84.8V
H to G: 121.9V
N to G: 27.9V

With the switch in the on position:

H to N: 0V
H to G: 121.9V
N to G: 121.9V
==== Any chance you've mixed up your terminology here? H to N
should be 120V and H to G 0V.
N (Neutral) is the white wire. The 120V should be appearing
across the H to N wiring (black/white and/or red/white).
G is Earth Ground, and is usually a bare wire though sometimes
they might have green insulation. IFF the G is connected, you
should also read the 120V between H and G. N and G get tied
together back at the breaker box. Do NOT tie them together
inside the receptacle/switch!!!!!!!!
I'ts likely OK if the G isn't connected to anything, as long
as no equipment is connected that requires a system ground (third
wire).

I'm confused. Anyone out there know what could possibly be
going on
with this switch?
==== I think nothing. You could stop by RS and pick up a cheap
tester for this purpose if you want to prove they're phantom
voltages you're reading. Or, you coujld rig one up yourself by
using a light bulb. With a light bulb across a phantom voltage,
the voltage will drop to a 0.0V reading immediately as the light
is attached.

Thanks.


Luck figuring out what it controls!

Pop

Digital voltmeters are often misleading. The only thing you generally need
to know to troubleshoot a power system is whether or not full voltage is
present between two wires. Sometimes you need to know whether or not there
is continuity between two wires. A test light and a continuity tester will
work much better.

The connection of the black wires is merely to feed power constantly thru
that box to somewhere else and the red wire is the switched hot wire. It may
go to a receptacle and the receptacle may be split so that one side is
always on from the black wire while the other side is controlled by the
switch.
Don Young
"John Grabowski" wrote in message
...

"Max" wrote in message
oups.com...
Hi,

I'm currently helping my girlfriend figure out what a switch in a spare
bedroom actually goes to, however I ran into a problem with voltages on
the switch.

Here's the setup:

1 - 12-2+G
1 - 12-3+G going into the box.

Black from 12-2 goes to top screw poll of switch
Black from 12-3 goes to top push fit poll of switch
Red from 12-3 goes to bottom poll of switch
Whites are bonded
Grounds are bonded, pigtail not connected to anything

From what little electrical I know, this seems like a 3 way switch
setup, however I have no idea where it could possibly go to. Also, if
it is a 3 way setup, I know the switch isn't a 3 way switch, so there's
no real way this should work anyway. I know it doesn't go to any of
the outlets in the room as they get a full 120V on top and bottom at
all times.

My concern is the voltages I'm reading on the switch.

With the switch in the off position I get:

H to N: 84.8V
H to G: 121.9V
N to G: 27.9V

With the switch in the on position:

H to N: 0V
H to G: 121.9V
N to G: 121.9V

I'm confused. Anyone out there know what could possibly be going on
with this switch?

Thanks.


It is not a 3 way switch set. The two blacks are joined together at the
switch instead of being spliced together with a wire connector. Usually
the
black is feeding through on the 3 wire and the red is the switch leg. If
you disconnected all of the wires you may find that the 2 wire is the feed
and you should have approximately 120 volts between the white and black.
See
what doesn't work after you disconnect the black wires. There could be a
ceiling fixture box that has been covered over. It is possible that there
was a switched receptacle at one time and the previous owner changed it to
be on all of the time. Open each outlet and look for the red wire.

How old is the house?

Stop using a voltmeter and get a pigtail socket and a light bulb and check
every outlet top and bottom again.