OK, here's today's electric circuit puzzle:

Client wants a new ceiling fan installed. The old one works, they just
want a different one up there. No problemo, right?

The new fan has a light, just like the old one (actually several hanging
sockets). Unlike the old one, though, the new one has only 3 wires: hots
for the fan and light, and a common neutral. Ugh. Not the way I would
have designed it.

I hook it up, figuring that I can simply use one of the neutrals in the
ceiling box and not the other one. Try it: light doesn't work at all,
while the fan does. That's weird.

So I go up there and measure voltages between wires. Here's what I get
(apologies to those who don't use monospaced fonts):

(1) blk X---- ----X blk (2)
fan light
(3) wht X---- ----X wht (4)


Measured voltages:

1 2 3 4
-------------------------------
1 90* 120 240
-------------------------------
2 90* 0 90
-------------------------------
3 120 0 120
-------------------------------
4 240 90 120
-------------------------------

* The 90 volt readings are from the dimmer switch all the way up.


Hmmm; something ain't right.

I ended up putting the old fan back up, as I couldn't get to any of the
wiring above the ceiling and we decided to leave well enough alone.

I figured out what was wrong after I got back home. It's actually pretty
simple.

For the solution, look he
http://www.geocities.com/bonezphoto/...redCircuit.gif


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

On Feb 8, 6:58*pm, David Nebenzahl wrote:
OK, here's today's electric circuit puzzle:

Client wants a new ceiling fan installed. The old one works, they just
want a different one up there. No problemo, right?

The new fan has a light, just like the old one (actually several hanging
sockets). Unlike the old one, though, the new one has only 3 wires: hots
for the fan and light, and a common neutral. Ugh. Not the way I would
have designed it.

I hook it up, figuring that I can simply use one of the neutrals in the
ceiling box and not the other one. Try it: light doesn't work at all,
while the fan does. That's weird.

So I go up there and measure voltages between wires. Here's what I get
(apologies to those who don't use monospaced fonts):

* * * * *(1) blk * X---- * ----X * blk (2)
* *fan * * * * * * * * * * * * * * * * * * * light
* * * * *(3) wht * X---- * ----X * wht (4)

Measured voltages:

* * * * * *1 * * *2 * * *3 * * *4
* * * -------------------------------
* * *1 * * * * * *90* * 120 * *240
* * * -------------------------------
* * *2 * * 90* * * * * * 0 * * *90
* * * -------------------------------
* * *3 * *120 * * 0 * * * * * *120
* * * -------------------------------
* * *4 * *240 * * 90 * *120
* * * -------------------------------

* The 90 volt readings are from the dimmer switch all the way up.

Hmmm; something ain't right.

I ended up putting the old fan back up, as I couldn't get to any of the
wiring above the ceiling and we decided to leave well enough alone.

I figured out what was wrong after I got back home. It's actually pretty
simple.

For the solution, look hehttp://www.geocities.com/bonezphoto/...redCircuit.gif

--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

that is crazy to have 240 volts going to one box like that... I would
rewire that circuit at the box so that it is all on one phase
(polarity is actually the correct term) ...

I'm sure the code experts will chime in shortly..

Mark

On 2/8/2009 7:06 PM spake thus:

On Feb 8, 6:58 pm, David Nebenzahl wrote:
OK, here's today's electric circuit puzzle:

Client wants a new ceiling fan installed. The old one works, they just
want a different one up there. No problemo, right?

The new fan has a light, just like the old one (actually several hanging
sockets). Unlike the old one, though, the new one has only 3 wires: hots
for the fan and light, and a common neutral. Ugh. Not the way I would
have designed it.

I hook it up, figuring that I can simply use one of the neutrals in the
ceiling box and not the other one. Try it: light doesn't work at all,
while the fan does. That's weird.

So I go up there and measure voltages between wires. Here's what I get
(apologies to those who don't use monospaced fonts):

(1) blk X---- ----X blk (2)
fan light
(3) wht X---- ----X wht (4)

Measured voltages:

1 2 3 4
-------------------------------
1 90* 120 240
-------------------------------
2 90* 0 90
-------------------------------
3 120 0 120
-------------------------------
4 240 90 120
-------------------------------

* The 90 volt readings are from the dimmer switch all the way up.

Hmmm; something ain't right.

I ended up putting the old fan back up, as I couldn't get to any of the
wiring above the ceiling and we decided to leave well enough alone.

I figured out what was wrong after I got back home. It's actually pretty
simple.

For the solution, look hehttp://www.geocities.com/bonezphoto/...redCircuit.gif

that is crazy to have 240 volts going to one box like that... I would
rewire that circuit at the box so that it is all on one phase
(polarity is actually the correct term) ...

I'm sure the code experts will chime in shortly..

Well, duh. It's ****ed up; that's why I posted this.

I would have fixed it if I could, but as I said, there's no access to
that part of the attic crawlspace. It works fine as is; that old saw
applies: "if it ain't broke, don't fix it."


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

On 2/8/2009 7:06 PM spake thus:

that is crazy to have 240 volts going to one box like that... I would
rewire that circuit at the box so that it is all on one phase
(polarity is actually the correct term) ...

That does raise an interesting question, though: if you had 2 circuits
connected to opposite sides of the incoming service in the same box,
then you'd have 240 volts between the hot wires. It would work fine, but
is there any code restriction against this? I don't know of any, but I
ain't no expert ...


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

On Sun, 8 Feb 2009 19:06:42 -0800 (PST), wrote:

On Feb 8, 6:58*pm, David Nebenzahl wrote:
OK, here's today's electric circuit puzzle:

Client wants a new ceiling fan installed. The old one works, they just
want a different one up there. No problemo, right?

The new fan has a light, just like the old one (actually several hanging
sockets). Unlike the old one, though, the new one has only 3 wires: hots
for the fan and light, and a common neutral. Ugh. Not the way I would
have designed it.

I hook it up, figuring that I can simply use one of the neutrals in the
ceiling box and not the other one. Try it: light doesn't work at all,
while the fan does. That's weird.

So I go up there and measure voltages between wires. Here's what I get
(apologies to those who don't use monospaced fonts):

* * * * *(1) blk * X---- * ----X * blk (2)
* *fan * * * * * * * * * * * * * * * * * * * light
* * * * *(3) wht * X---- * ----X * wht (4)

Measured voltages:

* * * * * *1 * * *2 * * *3 * * *4
* * * -------------------------------
* * *1 * * * * * *90* * 120 * *240
* * * -------------------------------
* * *2 * * 90* * * * * * 0 * * *90
* * * -------------------------------
* * *3 * *120 * * 0 * * * * * *120
* * * -------------------------------
* * *4 * *240 * * 90 * *120
* * * -------------------------------

* The 90 volt readings are from the dimmer switch all the way up.

Hmmm; something ain't right.

I ended up putting the old fan back up, as I couldn't get to any of the
wiring above the ceiling and we decided to leave well enough alone.

I figured out what was wrong after I got back home. It's actually pretty
simple.

For the solution, look hehttp://www.geocities.com/bonezphoto/...redCircuit.gif

--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

that is crazy to have 240 volts going to one box like that... I would
rewire that circuit at the box so that it is all on one phase
(polarity is actually the correct term) ...

I'm sure the code experts will chime in shortly..

Mark
The drawing doesn't make much sense to me.

The biggest code violation is the dimmer is in the neutral. You can't
switch the neutral.

Also the fan will run all the time.

Also I don't know how you get 90V from black to black. You should get
240V on one and 0V on the other.

He is also marking a hot leg black on one end and white on the other.

It is a puzzle alright. It is not an electrical circuit.

On 2/8/2009 7:43 PM metspitzer spake thus:

The drawing doesn't make much sense to me.

The biggest code violation is the dimmer is in the neutral. You can't
switch the neutral.

Also the fan will run all the time.

Also I don't know how you get 90V from black to black. You should get
240V on one and 0V on the other.

He is also marking a hot leg black on one end and white on the other.

It is a puzzle alright. It is not an electrical circuit.

Maybe it's not the best drawing in the world, but it shows what's there
accurately.

The 90 volts is on account of the dimmer, which apparently doesn't allow
the full 120 to get through.

The black and white wire markings are what exist. I know they're wrong;
that's the whole point. (I didn't do this wiring; I only came to install
a device in the box. Not my fault.)


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

"David Nebenzahl" wrote in message
.com...
OK, here's today's electric circuit puzzle:

Client wants a new ceiling fan installed. The old one works, they just
want a different one up there. No problemo, right?

The new fan has a light, just like the old one (actually several hanging
sockets). Unlike the old one, though, the new one has only 3 wires: hots
for the fan and light, and a common neutral. Ugh. Not the way I would have
designed it.

I hook it up, figuring that I can simply use one of the neutrals in the
ceiling box and not the other one. Try it: light doesn't work at all,
while the fan does. That's weird.

So I go up there and measure voltages between wires. Here's what I get
(apologies to those who don't use monospaced fonts):

(1) blk X---- ----X blk (2)
fan light
(3) wht X---- ----X wht (4)


Measured voltages:

1 2 3 4
-------------------------------
1 90* 120 240
-------------------------------
2 90* 0 90
-------------------------------
3 120 0 120
-------------------------------
4 240 90 120
-------------------------------

* The 90 volt readings are from the dimmer switch all the way up.


Hmmm; something ain't right.

I ended up putting the old fan back up, as I couldn't get to any of the
wiring above the ceiling and we decided to leave well enough alone.

I figured out what was wrong after I got back home. It's actually pretty
simple.

For the solution, look he
http://www.geocities.com/bonezphoto/...redCircuit.gif


*From your diagram it seems that you have 240 volts split between the fan
and the light and the neutral is switched using a dimmer. If that is the
case when the dimmer is off you will have 240 flowing through the light and
fan motor. This is not good. Personally I think that you have an
obligation as an electrician to inform the customer of the problem and its
hazards and tell them what it will cost to correct it. I would do this in
writing and let the customer decide how he/she wants to proceed.

On Sun, 08 Feb 2009 19:52:47 -0800, David Nebenzahl
wrote:

On 2/8/2009 7:43 PM metspitzer spake thus:

The drawing doesn't make much sense to me.

The biggest code violation is the dimmer is in the neutral. You can't
switch the neutral.

Also the fan will run all the time.

Also I don't know how you get 90V from black to black. You should get
240V on one and 0V on the other.

He is also marking a hot leg black on one end and white on the other.

It is a puzzle alright. It is not an electrical circuit.

Maybe it's not the best drawing in the world, but it shows what's there
accurately.

The 90 volts is on account of the dimmer, which apparently doesn't allow
the full 120 to get through.

The black and white wire markings are what exist. I know they're wrong;
that's the whole point. (I didn't do this wiring; I only came to install
a device in the box. Not my fault.)

You can hook it up right. The only thing that is wrong is that the
dimmer needs to go in the hot leg.

You have one circuit for the fan, which stays on all the time and one
circuit for the light, which is controlled by the dimmer.

The drawing looked so good, I thought it was designed to be a puzzle.
Sorry

I can't tell how it is physically wired, but putting the dimmer in the
neutral seemed like it was done just to cause 90V in some of the
readings.

On Feb 8, 5:58 pm, David Nebenzahl wrote:
[...]
I hook it up, figuring that I can simply use one of the neutrals in the
ceiling box and not the other one. Try it: light doesn't work at all,
while the fan does. That's weird.

Well, at least you avoided a cloud of smoke.

On 2/9/2009 8:54 AM John Grabowski spake thus:

"David Nebenzahl" wrote in message
.com...

For the solution, look he
http://www.geocities.com/bonezphoto/...redCircuit.gif

*From your diagram it seems that you have 240 volts split between the fan
and the light and the neutral is switched using a dimmer. If that is the
case when the dimmer is off you will have 240 flowing through the light and
fan motor.

No. When the dimmer is off (and that means totally off, infinite
resistance when the switch is flipped off), no current flows through the
light at all. The only place where there is 240 volts is between the hot
leg of the fan wires and the "neutral" (really the hot) of the light
wires. The fan is powered from the other leg of 120 and is completely
independent, electrically speaking, of the light; it just happens to be
wired in the same box.

This is not good.

No, it's not.

Personally I think that you have an obligation as an electrician to
inform the customer of the problem and its hazards and tell them what
it will cost to correct it. I would do this in writing and let the
customer decide how he/she wants to proceed.

I have told them. There really is no hazard with the wiring as it is,
electrically speaking. There may be problems later with anyone trying to
work on this circuit: I'm going to provide the client with a diagram in
case they need work done later.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

On Feb 8, 10:52*pm, David Nebenzahl wrote:
On 2/8/2009 7:43 PM metspitzer spake thus:

The drawing doesn't make much sense to me.

The biggest code violation is the dimmer is in the neutral. *You can't
switch the neutral.

Also the fan will run all the time.

Also I don't know how you get 90V from black to black. *You should get
240V on one and 0V on the other.

He is also marking a hot leg black on one end and white on the other.

It is a puzzle alright. *It is not an electrical circuit.

Maybe it's not the best drawing in the world, but it shows what's there
accurately.

The 90 volts is on account of the dimmer, which apparently doesn't allow
the full 120 to get through.

The black and white wire markings are what exist. I know they're wrong;
that's the whole point. (I didn't do this wiring; I only came to install
a device in the box. Not my fault.)

--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

My guess is that the switch is not in the neutral but it is in the
white wire of a switch loop (legal).
This could also acount for the 90 volt reading.

I think it is wired right. The OP just doesnt understand what he is
seeing. Hes been confused by phantom readings from a high impedance
volt meter.

Jimmie

On 2/9/2009 12:08 PM JIMMIE spake thus:

On Feb 8, 10:52 pm, David Nebenzahl wrote:
On 2/8/2009 7:43 PM metspitzer spake thus:

The drawing doesn't make much sense to me.

The biggest code violation is the dimmer is in the neutral. You can't
switch the neutral.

Also the fan will run all the time.

Also I don't know how you get 90V from black to black. You should get
240V on one and 0V on the other.

He is also marking a hot leg black on one end and white on the other.

It is a puzzle alright. It is not an electrical circuit.

Maybe it's not the best drawing in the world, but it shows what's there
accurately.

The 90 volts is on account of the dimmer, which apparently doesn't allow
the full 120 to get through.

The black and white wire markings are what exist. I know they're wrong;
that's the whole point. (I didn't do this wiring; I only came to install
a device in the box. Not my fault.)

My guess is that the switch is not in the neutral but it is in the
white wire of a switch loop (legal).
This could also acount for the 90 volt reading.

I think it is wired right. The OP just doesnt understand what he is
seeing. Hes been confused by phantom readings from a high impedance
volt meter.

Nope.

If it's wired correctly, then how do you account for the reading of 240
volts (definitely not a "phantom" reading, but a very real electrical
potential) between a hot wire and a neutral wire? That should never
happen in domestic wiring. Think about it.

This whole business of "phantom" readings due to high-impedance DMMs is
highly overstated, in my opinion. Yes, it can happen, but not very
often. Otherwise, one couldn't trust any readings taken with the damn
things, really.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair