Switch polarity question (electrical)
 

Up in the attic. Have to bring hot wire to junction box with three legs
going out. Each leg goes to ceiling light of different rooms. YES, I can
power them up and the wall switch in each room turns on its respective
light. BUT, what's an easy way to test that I don't have hot and neutral
reversed. The old romex in the attic (two wire, cloth wrapped) is NOT color
coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the bulb
socket in each room? Is there an easier way? My A.C. voltmeter obviously
does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I have
to solve this today!

Ivan Vegvary

Switch polarity question (electrical)
 

Ivan Vegvary wrote:
....
... The old romex in the attic (two wire, cloth
wrapped) is NOT color coded in any way.

Every old cable I've seen is coded in some way -- how else could they
have kept track originally, either?

Look for a stripe, a ridge, something that distinguishes the orientation
of the cable itself.

--

Switch polarity question (electrical)
 

Ivan Vegvary wrote:
Up in the attic. Have to bring hot wire to junction box with three legs
going out. Each leg goes to ceiling light of different rooms. YES, I
can power them up and the wall switch in each room turns on its
respective light. BUT, what's an easy way to test that I don't have hot
and neutral reversed. The old romex in the attic (two wire, cloth
wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the
bulb socket in each room? Is there an easier way? My A.C. voltmeter
obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I
have to solve this today!

Ivan Vegvary

better, drag a wire from a good ground (water pipe) and check voltage
against that. Heck, if you're in the attic, why not just add
supplemental grounds and/or pull new romex to replace the old cloth NM?
If you can't pull the whole circuit, do what you can and then wire a
supplemental ground from where you started repulling. Best would be to
take it back to the breaker box but if you can't do that any ground
point is acceptable per code (unless they've changed it recently.) Only
thing that *wouldn't* be acceptable would be to repull some of a circuit
so it would appear to be grounded but to not actually connect the ground
wire to a real ground.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

Switch polarity question (electrical)
 

Ivan Vegvary wrote:
Up in the attic. Have to bring hot wire to junction box with three legs
going out. Each leg goes to ceiling light of different rooms. YES, I
can power them up and the wall switch in each room turns on its
respective light. BUT, what's an easy way to test that I don't have hot
and neutral reversed. The old romex in the attic (two wire, cloth
wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the
bulb socket in each room? Is there an easier way? My A.C. voltmeter
obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I
have to solve this today!

Ivan Vegvary


I'll assume that the presence of two wire romex means that none of the
outlet boxes themselves are grounded, so you can't use them to test against.

No warranty on this advice, but if you're using an "electronic"
(digital) voltmeter, and are standing on something which insulates you
from ground, then you can jsut touch one of the voltmeter leads with
your hand and probe the shell and center contacts of the sockets with
the other lead.

Your body capacitance will provide enough of a load to cause the
voltmeter to indicate some voltage when it's lead is connected to the
"hot" side iof the line. It probably won't read the full 120 volts, but
enough so you can easily tell the difference.

There are commercial testers which will do what you want to do, if you
want to spring a few bucks for one:

http://www.tecratools.com/product492.html

But, if you've already got a sensitive AC voltmeter, try my suggestion.

Jeff


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

Switch polarity question (electrical)
 

"Jeff Wisnia" wrote in message
mmunications...
Ivan Vegvary wrote:
Up in the attic. Have to bring hot wire to junction box with three legs
going out. Each leg goes to ceiling light of different rooms. YES, I
can power them up and the wall switch in each room turns on its
respective light. BUT, what's an easy way to test that I don't have hot
and neutral reversed. The old romex in the attic (two wire, cloth
wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the
bulb socket in each room? Is there an easier way? My A.C. voltmeter
obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I
have to solve this today!

Ivan Vegvary


I'll assume that the presence of two wire romex means that none of the
outlet boxes themselves are grounded, so you can't use them to test
against.

No warranty on this advice, but if you're using an "electronic" (digital)
voltmeter, and are standing on something which insulates you from ground,
then you can jsut touch one of the voltmeter leads with your hand and
probe the shell and center contacts of the sockets with the other lead.

Your body capacitance will provide enough of a load to cause the voltmeter
to indicate some voltage when it's lead is connected to the "hot" side iof
the line. It probably won't read the full 120 volts, but enough so you can
easily tell the difference.

There are commercial testers which will do what you want to do, if you
want to spring a few bucks for one:

http://www.tecratools.com/product492.html

But, if you've already got a sensitive AC voltmeter, try my suggestion.

Jeff


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

THANKS JEFF!!!!!!!

Switch polarity question (electrical)
 

"Jeff Wisnia" wrote in message
mmunications...
Ivan Vegvary wrote:
Up in the attic. Have to bring hot wire to junction box with three legs
going out. Each leg goes to ceiling light of different rooms. YES, I
can power them up and the wall switch in each room turns on its
respective light. BUT, what's an easy way to test that I don't have hot
and neutral reversed. The old romex in the attic (two wire, cloth
wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the
bulb socket in each room? Is there an easier way? My A.C. voltmeter
obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I
have to solve this today!

Ivan Vegvary


I'll assume that the presence of two wire romex means that none of the
outlet boxes themselves are grounded, so you can't use them to test
against.

No warranty on this advice, but if you're using an "electronic" (digital)
voltmeter, and are standing on something which insulates you from ground,
then you can jsut touch one of the voltmeter leads with your hand and
probe the shell and center contacts of the sockets with the other lead.

Your body capacitance will provide enough of a load to cause the voltmeter
to indicate some voltage when it's lead is connected to the "hot" side iof
the line. It probably won't read the full 120 volts, but enough so you can
easily tell the difference.

Even if you are using a real cheap neon tester, this method works to find a
hot wire, Just hold the end of one lead and touch the other to the wires,
the neon bulb will light up dimly when you hit a hot wire. You won't feel a
thing.

Switch polarity question (electrical)
 

On Fri, 28 Nov 2008 07:12:37 -0800, "Ivan Vegvary"
wrote:

Up in the attic. Have to bring hot wire to junction box with three legs
going out. Each leg goes to ceiling light of different rooms. YES, I can
power them up and the wall switch in each room turns on its respective
light. BUT, what's an easy way to test that I don't have hot and neutral
reversed. The old romex in the attic (two wire, cloth wrapped) is NOT color
coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the bulb
socket in each room? Is there an easier way? My A.C. voltmeter obviously
does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I have
to solve this today!

Ivan Vegvary


There are plug-in inexpensive testers to tell you from hot and
neutral. Many just plug into an outlet, but I'm sure you can get one
of those screw-in sockets that would allow you to plug the tester in.

Switch polarity question (electrical)
 

On Fri, 28 Nov 2008 07:38:01 -0800, "Ivan Vegvary"
wrote:


"Jeff Wisnia" wrote in message
mmunications...
Ivan Vegvary wrote:
Up in the attic. Have to bring hot wire to junction box with three legs
going out. Each leg goes to ceiling light of different rooms. YES, I
can power them up and the wall switch in each room turns on its
respective light. BUT, what's an easy way to test that I don't have hot
and neutral reversed. The old romex in the attic (two wire, cloth
wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the
bulb socket in each room? Is there an easier way? My A.C. voltmeter
obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I
have to solve this today!

Ivan Vegvary


I'll assume that the presence of two wire romex means that none of the
outlet boxes themselves are grounded, so you can't use them to test
against.

No warranty on this advice, but if you're using an "electronic" (digital)
voltmeter, and are standing on something which insulates you from ground,
then you can jsut touch one of the voltmeter leads with your hand and
probe the shell and center contacts of the sockets with the other lead.

Your body capacitance will provide enough of a load to cause the voltmeter
to indicate some voltage when it's lead is connected to the "hot" side iof
the line. It probably won't read the full 120 volts, but enough so you can
easily tell the difference.

There are commercial testers which will do what you want to do, if you
want to spring a few bucks for one:

http://www.tecratools.com/product492.html

But, if you've already got a sensitive AC voltmeter, try my suggestion.

They also make what is called a touch voltage tester.
I don't know if you can get them at builder supplies but you can get
them at an electrical supply.

http://www.ehow.com/how_2237961_test-for-voltage.html

Switch polarity question (electrical)
 

Phisherman wrote:
On Fri, 28 Nov 2008 07:12:37 -0800, "Ivan Vegvary"
wrote:


Up in the attic. Have to bring hot wire to junction box with three legs
going out. Each leg goes to ceiling light of different rooms. YES, I can
power them up and the wall switch in each room turns on its respective
light. BUT, what's an easy way to test that I don't have hot and neutral
reversed. The old romex in the attic (two wire, cloth wrapped) is NOT color
coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the bulb
socket in each room? Is there an easier way? My A.C. voltmeter obviously
does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I have
to solve this today!

Ivan Vegvary



There are plug-in inexpensive testers to tell you from hot and
neutral. Many just plug into an outlet, but I'm sure you can get one
of those screw-in sockets that would allow you to plug the tester in.


I believ those only work if they are used on a circuit with a ground
available. I don't see how they could work with one of those screw-in
socket adapters.

Someone please correct me if I'm wrong, please.

Jeff

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

Switch polarity question (electrical)
 

"Ivan Vegvary" wrote in message
...
Up in the attic. Have to bring hot wire to junction box with three legs
going out. Each leg goes to ceiling light of different rooms. YES, I can
power them up and the wall switch in each room turns on its respective
light. BUT, what's an easy way to test that I don't have hot and neutral
reversed. The old romex in the attic (two wire, cloth wrapped) is NOT
color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the
bulb socket in each room? Is there an easier way? My A.C. voltmeter
obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I have
to solve this today!

Ivan Vegvary


I always have my little inductive tester with me to figure out which wire is
hot. You just touch it to the insulation and it only gives an indication on
the hot wire. It can also read through the outer jacket on Romex. I've
used several brands over the years, but have found the Fluke model to give
the least amount of false readings.
http://us.fluke.com/usen/products/Fl...United States

Switch polarity question (electrical)
 

Up in the attic. Have to bring hot wire to junction box with three
legs going out. Each leg goes to ceiling light of different rooms.
YES, I can power them up and the wall switch in each room turns on
its respective light. BUT, what's an easy way to test that I don't
have hot and neutral reversed. The old romex in the attic (two wire,
cloth wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe
the bulb socket in each room? Is there an easier way? My A.C.
voltmeter obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I
have to solve this today!

Ivan Vegvary

It's not an actual polarity you want; remember, this is ac. The
"polarity" applies to which is hot and which is neutra.

Arbitrarily assign one as Hot (H); use the wire to the hot connection on
the fixture as H:
Find an Earth Ground (receptacles are probably earthed).
Then, check
H - N 120V
H - Earth 120V
N - Earth 0V

If H - N = 0 then N - Earth should be 120V, meaning they are reversed.
Switch the wires with each other.

Assumption: Neutral and Earth are ONLY joined back at the breaker box
and nowhere else!
Validate Earth connection by turning off all power (Mains). Use your
ohmmeter to measure the resistance between Neutral and Earth. It should
only be a few ohms, depending on the length of wire involved, or maybe
0.0.
SWITCH YOUR METER OFF OHMS AS SOON AS DONE, so you don't accidentally
try to measure voltage with it.
The reason to turn off all power is that, should the polarity be
wrong, you will fry your ohmmeter. I always check first for voltage and
only after knowing it's not 120 V ac do I switch it to ohms. Then as
soon as I finish ohmming thngs out, I put it back to measure ac voltage.

HTH

Twayne

Switch polarity question (electrical)
 

Ivan Vegvary wrote:
Up in the attic. Have to bring hot wire to junction box with three
legs going out. Each leg goes to ceiling light of different rooms.
YES, I can power them up and the wall switch in each room turns on
its respective light. BUT, what's an easy way to test that I don't
have hot and neutral reversed. The old romex in the attic (two
wire, cloth wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe
the bulb socket in each room? Is there an easier way? My A.C.
voltmeter obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and I
have to solve this today!

Ivan Vegvary

better, drag a wire from a good ground (water pipe) and check voltage
against that. Heck, if you're in the attic, why not just add
supplemental grounds and/or pull new romex to replace the old cloth
NM? If you can't pull the whole circuit, do what you can and then
wire a supplemental ground from where you started repulling. Best
would be to take it back to the breaker box but if you can't do that
any ground point is acceptable per code (unless they've changed it
recently.) Only thing that *wouldn't* be acceptable would be to
repull some of a circuit so it would appear to be grounded but to not
actually connect the ground wire to a real ground.

nate

Well, some local codes have problems with things like that, but ... when
it's that old you aren't likely to get much objection to improving the
safety of the ckt if that's all you can afford or manage. I've even
seen some knob & tube with earth grounds.


That's a good point; if the insulation is that old, beware the
insulation falling apart in your hands and possibly already being
missing from some parts of the wires. Especially if there have been any
varmints running around there.

Switch polarity question (electrical)
 

"Jeff Wisnia" wrote in message
mmunications...
Ivan Vegvary wrote:
Up in the attic. Have to bring hot wire to junction box with three
legs going out. Each leg goes to ceiling light of different rooms.
YES, I can power them up and the wall switch in each room turns on
its respective light. BUT, what's an easy way to test that I don't
have hot and neutral reversed. The old romex in the attic (two
wire, cloth wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe
the bulb socket in each room? Is there an easier way? My A.C.
voltmeter obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and
I have to solve this today!

Ivan Vegvary


I'll assume that the presence of two wire romex means that none of
the outlet boxes themselves are grounded, so you can't use them to
test against.

No warranty on this advice, but if you're using an "electronic"
(digital) voltmeter, and are standing on something which insulates
you from ground, then you can jsut touch one of the voltmeter leads
with your hand and probe the shell and center contacts of the
sockets with the other lead. Your body capacitance will provide
enough of a load to cause the
voltmeter to indicate some voltage when it's lead is connected to
the "hot" side iof the line. It probably won't read the full 120
volts, but enough so you can easily tell the difference.

Even if you are using a real cheap neon tester, this method works to
find a hot wire, Just hold the end of one lead and touch the other to
the wires, the neon bulb will light up dimly when you hit a hot wire.
You won't feel a thing.

Good suggestion; that also helps with the confusion sometimes that
phantom voltages present.

Switch polarity question (electrical)
 

Phisherman wrote:
On Fri, 28 Nov 2008 07:12:37 -0800, "Ivan Vegvary"
wrote:


Up in the attic. Have to bring hot wire to junction box with three
legs going out. Each leg goes to ceiling light of different rooms.
YES, I can power them up and the wall switch in each room turns on
its respective light. BUT, what's an easy way to test that I don't
have hot and neutral reversed. The old romex in the attic (two
wire, cloth wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe
the bulb socket in each room? Is there an easier way? My A.C.
voltmeter obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and
I have to solve this today!

Ivan Vegvary



There are plug-in inexpensive testers to tell you from hot and
neutral. Many just plug into an outlet, but I'm sure you can get one
of those screw-in sockets that would allow you to plug the tester in.


I believ those only work if they are used on a circuit with a ground
available. I don't see how they could work with one of those screw-in
socket adapters.

Someone please correct me if I'm wrong, please.

Jeff

I can't speak for all of them, but mine works on two wire/no earth. In
fact, missing earth is one of the light sequences, right along wiht a
"missing" neutral. It can identify any of the 3 wires are missing. I
suspect they all can, no? This is just a cheapie Radio Shack tester.
GB is the only mfg ID I see on it.

It's also my second one; the first one grew legs apparently.

Switch polarity question (electrical)
 

On Nov 28, 12:12*pm, "Ivan Vegvary" wrote:
Up in the attic. *Have to bring hot wire to junction box with three legs
going out. *Each leg goes to ceiling light of different rooms. *YES, I can
power them up and the wall switch in each room turns on its respective
light. BUT, what's an easy way to test that I don't have hot and neutral
reversed. *The old romex in the attic (two wire, cloth wrapped) is NOT color
coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the bulb
socket in each room? *Is there an easier way? *My A.C. voltmeter obviously
does not indicate polarity.

All replies appreciated. *Sheetrock guy is coming tomorrow a.m. and I have
to solve this today!

Ivan Vegvary

That would be my quick suggestion also. Find a ground somewhere.
connect one side of your meter or one side of light bulb to that. With
lights switched on.

Any wire wire that has potential to that ground is most likely the
live (today black) wire and is either a direct live from the supply
fus/breaker or a switched live.

The wire that has zero or a very low potential to that ground
(although even cheap digital multimeters can be deceiving) is most
likely the neutral (white wire).

Don't mess around with readings of 30 or or some odd voltage on wires
which are disconnected or switched off. In fact a light bulb is often
a better tester than a meter that can pick up odd induced voltage from
other circuits or wires!

Switch polarity question (electrical)
 

On Nov 28, 9:42*am, Phisherman wrote:
On Fri, 28 Nov 2008 07:12:37 -0800, "Ivan Vegvary"
wrote:

Up in the attic. *Have to bring hot wire to junction box with three legs
going out. *Each leg goes to ceiling light of different rooms. *YES, I can
power them up and the wall switch in each room turns on its respective
light. BUT, what's an easy way to test that I don't have hot and neutral
reversed. *The old romex in the attic (two wire, cloth wrapped) is NOT color
coded in any way.

Do I simply drag a neutral wire from a different circuit and probe the bulb
socket in each room? *Is there an easier way? *My A.C. voltmeter obviously
does not indicate polarity.

All replies appreciated. *Sheetrock guy is coming tomorrow a.m. and I have
to solve this today!

Ivan Vegvary

There are plug-in inexpensive testers to tell you from hot and
neutral. *Many just plug into an outlet, but I'm sure you can get one
of those screw-in sockets that would allow you to plug the tester in.

But the plug-in testers assume that you have a 3-wire outlet to work
properly.

Bob H

Switch polarity question (electrical)
 

On Fri, 28 Nov 2008 10:47:03 -0500, metspitzer
wrote:

[snip]


They also make what is called a touch voltage tester.
I don't know if you can get them at builder supplies but you can get
them at an electrical supply.

http://www.ehow.com/how_2237961_test-for-voltage.html

Would that be the same as the $5 testers sold for holiday light
strings?

Switch polarity question (electrical)
 

On Nov 29, 11:04*am, Gary H wrote:
On Fri, 28 Nov 2008 10:47:03 -0500, metspitzer
wrote:

[snip]



They also make what is called a touch voltage tester.
I don't know if you can get them at builder supplies but you can get
them at an electrical supply.

http://www.ehow.com/how_2237961_test-for-voltage.html

Would that be the same as the $5 testers sold for holiday light
strings?

Yessir!

Switch polarity question (electrical)
 

Twayne wrote:
Phisherman wrote:
On Fri, 28 Nov 2008 07:12:37 -0800, "Ivan Vegvary"
wrote:


Up in the attic. Have to bring hot wire to junction box with three
legs going out. Each leg goes to ceiling light of different rooms.
YES, I can power them up and the wall switch in each room turns on
its respective light. BUT, what's an easy way to test that I don't
have hot and neutral reversed. The old romex in the attic (two
wire, cloth wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe
the bulb socket in each room? Is there an easier way? My A.C.
voltmeter obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and
I have to solve this today!

Ivan Vegvary


There are plug-in inexpensive testers to tell you from hot and
neutral. Many just plug into an outlet, but I'm sure you can get one
of those screw-in sockets that would allow you to plug the tester in.

I believ those only work if they are used on a circuit with a ground
available. I don't see how they could work with one of those screw-in
socket adapters.

Someone please correct me if I'm wrong, please.

Jeff

I can't speak for all of them, but mine works on two wire/no earth. In
fact, missing earth is one of the light sequences, right along wiht a
"missing" neutral. It can identify any of the 3 wires are missing. I
suspect they all can, no? This is just a cheapie Radio Shack tester.
GB is the only mfg ID I see on it.

If there is no ground it will tell you that.

But unless you have one I haven't seen, if there is no ground the tester
won't tell you if there is a H-N reverse. That is basically what Jeff asked.

It won't tell you if there is a high resistance (useless) ground.

In an unusual case of N tied to G (which some idiots do when there is no
ground available) and a H-N supply reverse it will indicate "normal".

--
bud--

Switch polarity question (electrical)
 

Twayne wrote:
Phisherman wrote:
On Fri, 28 Nov 2008 07:12:37 -0800, "Ivan Vegvary"
wrote:


Up in the attic. Have to bring hot wire to junction box with
three legs going out. Each leg goes to ceiling light of
different rooms. YES, I can power them up and the wall switch in
each room turns on its respective light. BUT, what's an easy way
to test that I don't have hot and neutral reversed. The old
romex in the attic (two wire, cloth wrapped) is NOT color coded
in any way. Do I simply drag a neutral wire from a different
circuit and probe
the bulb socket in each room? Is there an easier way? My A.C.
voltmeter obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m.
and I have to solve this today!

Ivan Vegvary


There are plug-in inexpensive testers to tell you from hot and
neutral. Many just plug into an outlet, but I'm sure you can get
one of those screw-in sockets that would allow you to plug the
tester in.

I believ those only work if they are used on a circuit with a ground
available. I don't see how they could work with one of those
screw-in socket adapters.

Someone please correct me if I'm wrong, please.

Jeff

I can't speak for all of them, but mine works on two wire/no earth.
In fact, missing earth is one of the light sequences, right along
wiht a "missing" neutral. It can identify any of the 3 wires are
missing. I suspect they all can, no? This is just a cheapie Radio
Shack tester. GB is the only mfg ID I see on it.

If there is no ground it will tell you that.

But unless you have one I haven't seen, if there is no ground the
tester won't tell you if there is a H-N reverse. That is basically
what Jeff asked.
It won't tell you if there is a high resistance (useless) ground.

In an unusual case of N tied to G (which some idiots do when there is
no ground available) and a H-N supply reverse it will indicate
"normal".

lol, not for long once the power is turned on!

Switch polarity question (electrical)
 

On Mon, 01 Dec 2008 11:14:58 -0600, bud--
wrote:

Twayne wrote:
Phisherman wrote:
On Fri, 28 Nov 2008 07:12:37 -0800, "Ivan Vegvary"
wrote:


Up in the attic. Have to bring hot wire to junction box with three
legs going out. Each leg goes to ceiling light of different rooms.
YES, I can power them up and the wall switch in each room turns on
its respective light. BUT, what's an easy way to test that I don't
have hot and neutral reversed. The old romex in the attic (two
wire, cloth wrapped) is NOT color coded in any way.

Do I simply drag a neutral wire from a different circuit and probe
the bulb socket in each room? Is there an easier way? My A.C.
voltmeter obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m. and
I have to solve this today!

Ivan Vegvary


There are plug-in inexpensive testers to tell you from hot and
neutral. Many just plug into an outlet, but I'm sure you can get one
of those screw-in sockets that would allow you to plug the tester in.

I believ those only work if they are used on a circuit with a ground
available. I don't see how they could work with one of those screw-in
socket adapters.

Someone please correct me if I'm wrong, please.

Jeff

I can't speak for all of them, but mine works on two wire/no earth. In
fact, missing earth is one of the light sequences, right along wiht a
"missing" neutral. It can identify any of the 3 wires are missing. I
suspect they all can, no? This is just a cheapie Radio Shack tester.
GB is the only mfg ID I see on it.

If there is no ground it will tell you that.

But unless you have one I haven't seen, if there is no ground the tester
won't tell you if there is a H-N reverse. That is basically what Jeff asked.

It won't tell you if there is a high resistance (useless) ground.

In an unusual case of N tied to G (which some idiots do when there is no
ground available) and a H-N supply reverse it will indicate "normal".


Actually a cheap NEON tester can tell you a LOT. It will tell you
which side is "hot", if one is. (capacitive connection with your
finger.

It will tell you if the ground is totally open (no "bright" light
across the socket) and it will tell you if you have a significant
ground problem (the ground side lights capacitively with a load
plugged into the socket)

Switch polarity question (electrical)
 

On Mon, 1 Dec 2008 15:54:45 -0500, "Twayne"
wrote:

Twayne wrote:
Phisherman wrote:
On Fri, 28 Nov 2008 07:12:37 -0800, "Ivan Vegvary"
wrote:


Up in the attic. Have to bring hot wire to junction box with
three legs going out. Each leg goes to ceiling light of
different rooms. YES, I can power them up and the wall switch in
each room turns on its respective light. BUT, what's an easy way
to test that I don't have hot and neutral reversed. The old
romex in the attic (two wire, cloth wrapped) is NOT color coded
in any way. Do I simply drag a neutral wire from a different
circuit and probe
the bulb socket in each room? Is there an easier way? My A.C.
voltmeter obviously does not indicate polarity.

All replies appreciated. Sheetrock guy is coming tomorrow a.m.
and I have to solve this today!

Ivan Vegvary


There are plug-in inexpensive testers to tell you from hot and
neutral. Many just plug into an outlet, but I'm sure you can get
one of those screw-in sockets that would allow you to plug the
tester in.

I believ those only work if they are used on a circuit with a ground
available. I don't see how they could work with one of those
screw-in socket adapters.

Someone please correct me if I'm wrong, please.

Jeff

I can't speak for all of them, but mine works on two wire/no earth.
In fact, missing earth is one of the light sequences, right along
wiht a "missing" neutral. It can identify any of the 3 wires are
missing. I suspect they all can, no? This is just a cheapie Radio
Shack tester. GB is the only mfg ID I see on it.

If there is no ground it will tell you that.

But unless you have one I haven't seen, if there is no ground the
tester won't tell you if there is a H-N reverse. That is basically
what Jeff asked.
It won't tell you if there is a high resistance (useless) ground.

In an unusual case of N tied to G (which some idiots do when there is
no ground available) and a H-N supply reverse it will indicate
"normal".

lol, not for long once the power is turned on!

Semantics. If the "u" ground on the receptacle ic connected to the
neutral, either at the plug or the panel, everythiing will work fine
except the case of every grounded device connected will be HOT.

If, however, the neutral is connected to a functional ground, and the
H-N wires are crossed, breakers and/or fuses will complain immediately
upon power-up.