I ran across this situation the other day and am confused.

There are two rooms in a commercial building. The larger room has 4
fluorescent fixtures in the ceiling. The second, smaller room has two. The
smaller room has a switch to turn on it's lights. However this is fed from
the larger room switch (first switch) and the small room switch (2nd
switch) only works if the first one is on.

So, I'm testing the power on the first switch to see which is power and
which is the switch leg, and accidently short out the switch and trip the
breaker. "Great" I think, at least I know which breaker controls the
lights. Sure enough, it's labeled "Lights" in the breaker box.

However, yesterday when I wanted to change out the switch. I noticed the
following.

1. If I turn off the switch all 6 lights go out (as is to be expected)

2. If the switch is on, and I turn off the breaker, the fluroescent bulbs
show a "glow" as if the power is on but reduced.

3. If the breaker is off and the switch is on, I measure about 85V at the
power side and switch leg of the switch. The lights have a "glow" as
above. (I think this diminishes with time and the lights finally go out)

4. If the breaker is on and the switch is off, I measure 135V at the power
side of the switch.

What I discovered is that there is a second breaker, labeled (Lights and
Heater (baseboard electric heater in the large room). If I turn this off
as well as the first one, there is no longer any power to the switch.

The wiring is a rat's nest of boxes and red wires to and from the switch
and fixtures (along with additional wires from other lights and outlets)
so it would be time consuming to trace where the wires come from and go.
It's commercial so I'm assuming that it was done to code, it's just
confusing.

I didn't check, but assumed that the fixtures were 120V rather than 240V.
Actually, I did notice that some only had one power wire going into them
so it's safe to assume that they're 120V.

Any suggestions as to what might be happening? I took out the switch
already, but will be back on Monday and can get additional info (assuming
this doesn't mean tracing wiring) then if you need it.

--
charles

You don't have enough information to do more than guess, but it may be
possible that there is an emergency backup system connected to these lights,
which itself is not working properly



"Charles Bishop" wrote in message
...
I ran across this situation the other day and am confused.

There are two rooms in a commercial building. The larger room has 4
fluorescent fixtures in the ceiling. The second, smaller room has two. The
smaller room has a switch to turn on it's lights. However this is fed from
the larger room switch (first switch) and the small room switch (2nd
switch) only works if the first one is on.

So, I'm testing the power on the first switch to see which is power and
which is the switch leg, and accidently short out the switch and trip the
breaker. "Great" I think, at least I know which breaker controls the
lights. Sure enough, it's labeled "Lights" in the breaker box.

However, yesterday when I wanted to change out the switch. I noticed the
following.

1. If I turn off the switch all 6 lights go out (as is to be expected)

2. If the switch is on, and I turn off the breaker, the fluroescent bulbs
show a "glow" as if the power is on but reduced.

3. If the breaker is off and the switch is on, I measure about 85V at the
power side and switch leg of the switch. The lights have a "glow" as
above. (I think this diminishes with time and the lights finally go out)

4. If the breaker is on and the switch is off, I measure 135V at the power
side of the switch.

What I discovered is that there is a second breaker, labeled (Lights and
Heater (baseboard electric heater in the large room). If I turn this off
as well as the first one, there is no longer any power to the switch.

The wiring is a rat's nest of boxes and red wires to and from the switch
and fixtures (along with additional wires from other lights and outlets)
so it would be time consuming to trace where the wires come from and go.
It's commercial so I'm assuming that it was done to code, it's just
confusing.

I didn't check, but assumed that the fixtures were 120V rather than 240V.
Actually, I did notice that some only had one power wire going into them
so it's safe to assume that they're 120V.

Any suggestions as to what might be happening? I took out the switch
already, but will be back on Monday and can get additional info (assuming
this doesn't mean tracing wiring) then if you need it.

--
charles

Charles Bishop wrote:
I ran across this situation the other day and am confused.


You have done a good job of describing what is almost certainly a
floating neutral. Some where along the line the white wire is not properly
connected or it is missing. If so you have a dangerous situation. I
suggest you turn off both breakers involved until you can check it or have
it checked. It can cause a fire and damage equipment.

Again ___ Turn off both of those breakers ____ !!!

--
Joseph Meehan

Dia 's Muire duit

is the voltage for the fixtures 120? 277? 240?

are the switches 3 ways? single pole?

need more info...

Commercial buildings usually have the 277 and they usually share the
neutrals.

as one poster mentioned there is emeergency lighting that could be
involved..



On Sun, 14 Jan 2007 10:03:20 -0800, tt (Charles
Bishop) wrote:

I ran across this situation the other day and am confused.

There are two rooms in a commercial building. The larger room has 4
fluorescent fixtures in the ceiling. The second, smaller room has two. The
smaller room has a switch to turn on it's lights. However this is fed from
the larger room switch (first switch) and the small room switch (2nd
switch) only works if the first one is on.

So, I'm testing the power on the first switch to see which is power and
which is the switch leg, and accidently short out the switch and trip the
breaker. "Great" I think, at least I know which breaker controls the
lights. Sure enough, it's labeled "Lights" in the breaker box.

However, yesterday when I wanted to change out the switch. I noticed the
following.

1. If I turn off the switch all 6 lights go out (as is to be expected)

2. If the switch is on, and I turn off the breaker, the fluroescent bulbs
show a "glow" as if the power is on but reduced.

3. If the breaker is off and the switch is on, I measure about 85V at the
power side and switch leg of the switch. The lights have a "glow" as
above. (I think this diminishes with time and the lights finally go out)

4. If the breaker is on and the switch is off, I measure 135V at the power
side of the switch.

What I discovered is that there is a second breaker, labeled (Lights and
Heater (baseboard electric heater in the large room). If I turn this off
as well as the first one, there is no longer any power to the switch.

The wiring is a rat's nest of boxes and red wires to and from the switch
and fixtures (along with additional wires from other lights and outlets)
so it would be time consuming to trace where the wires come from and go.
It's commercial so I'm assuming that it was done to code, it's just
confusing.

I didn't check, but assumed that the fixtures were 120V rather than 240V.
Actually, I did notice that some only had one power wire going into them
so it's safe to assume that they're 120V.

Any suggestions as to what might be happening? I took out the switch
already, but will be back on Monday and can get additional info (assuming
this doesn't mean tracing wiring) then if you need it.

You might have a shared neutral situation. I have a couple of circuits
in my house that share a neutral and the circuits are a pain to work
on. I get "bleeding" across circuits when only breaker is on and
certain switches are are certain positions.

I discovered this while trying to split up some circuits after I first
moved in. I killed the breaker for the circuit I wanted to work on,
removed a wire nut in a junction box and went upstairs to make sure the
correct outlet was dead. Luckily it was night time because when I went
upstairs I saw an overhead light from another circuit glowing slightly.
Had it been daytime, I probably would never had noticed it.

Made splitting up the circuits a bit more interesting!

Charles Bishop wrote:
I ran across this situation the other day and am confused.

There are two rooms in a commercial building. The larger room has 4
fluorescent fixtures in the ceiling. The second, smaller room has two. The
smaller room has a switch to turn on it's lights. However this is fed from
the larger room switch (first switch) and the small room switch (2nd
switch) only works if the first one is on.

So, I'm testing the power on the first switch to see which is power and
which is the switch leg, and accidently short out the switch and trip the
breaker. "Great" I think, at least I know which breaker controls the
lights. Sure enough, it's labeled "Lights" in the breaker box.

However, yesterday when I wanted to change out the switch. I noticed the
following.

1. If I turn off the switch all 6 lights go out (as is to be expected)

2. If the switch is on, and I turn off the breaker, the fluroescent bulbs
show a "glow" as if the power is on but reduced.

3. If the breaker is off and the switch is on, I measure about 85V at the
power side and switch leg of the switch. The lights have a "glow" as
above. (I think this diminishes with time and the lights finally go out)

4. If the breaker is on and the switch is off, I measure 135V at the power
side of the switch.

What I discovered is that there is a second breaker, labeled (Lights and
Heater (baseboard electric heater in the large room). If I turn this off
as well as the first one, there is no longer any power to the switch.

The wiring is a rat's nest of boxes and red wires to and from the switch
and fixtures (along with additional wires from other lights and outlets)
so it would be time consuming to trace where the wires come from and go.
It's commercial so I'm assuming that it was done to code, it's just
confusing.

I didn't check, but assumed that the fixtures were 120V rather than 240V.
Actually, I did notice that some only had one power wire going into them
so it's safe to assume that they're 120V.

Any suggestions as to what might be happening? I took out the switch
already, but will be back on Monday and can get additional info (assuming
this doesn't mean tracing wiring) then if you need it.

--
charles

Keep in mind, when you turn off fluorescent lights and have a totally dark
room, there is often an after-glow that is visible from the bulbs. This is a
natural occurrence to fluorescent bulbs. I used to have a photo darkroom
with fluorescent lights, you would have to wait until the glow was fully
extinguished before you could open any film boxes or you would fog the film.
The fluorescent bulbs were primarily used for cleaning and maintaining
equipment and chemical balances, incandescent bulbs were used for
"safe-lights".


"Charles Bishop" wrote in message
...
I ran across this situation the other day and am confused.

There are two rooms in a commercial building. The larger room has 4
fluorescent fixtures in the ceiling. The second, smaller room has two. The
smaller room has a switch to turn on it's lights. However this is fed from
the larger room switch (first switch) and the small room switch (2nd
switch) only works if the first one is on.

So, I'm testing the power on the first switch to see which is power and
which is the switch leg, and accidently short out the switch and trip the
breaker. "Great" I think, at least I know which breaker controls the
lights. Sure enough, it's labeled "Lights" in the breaker box.

However, yesterday when I wanted to change out the switch. I noticed the
following.

1. If I turn off the switch all 6 lights go out (as is to be expected)

2. If the switch is on, and I turn off the breaker, the fluroescent bulbs
show a "glow" as if the power is on but reduced.

3. If the breaker is off and the switch is on, I measure about 85V at the
power side and switch leg of the switch. The lights have a "glow" as
above. (I think this diminishes with time and the lights finally go out)

4. If the breaker is on and the switch is off, I measure 135V at the power
side of the switch.

What I discovered is that there is a second breaker, labeled (Lights and
Heater (baseboard electric heater in the large room). If I turn this off
as well as the first one, there is no longer any power to the switch.

The wiring is a rat's nest of boxes and red wires to and from the switch
and fixtures (along with additional wires from other lights and outlets)
so it would be time consuming to trace where the wires come from and go.
It's commercial so I'm assuming that it was done to code, it's just
confusing.

I didn't check, but assumed that the fixtures were 120V rather than 240V.
Actually, I did notice that some only had one power wire going into them
so it's safe to assume that they're 120V.

Any suggestions as to what might be happening? I took out the switch
already, but will be back on Monday and can get additional info (assuming
this doesn't mean tracing wiring) then if you need it.

--
charles