Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?

Every time someone tells me that wiring should be done by a
"professional" I run into another example of egregiously bad wiring
installed by a "professional".

Well, I know now how I'm going spend some part of my vacation. And I
hate to admit it but I'm getting too _old_ to be rolling around in
fiberglass pulling wires for fun and no profit. I know, I should hire
an electrician but then I'll have to watch him.

On Sun, 21 Mar 2021 16:33:14 -0400, J. Clarke
wrote:

Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?

Every time someone tells me that wiring should be done by a
"professional" I run into another example of egregiously bad wiring
installed by a "professional".

Well, I know now how I'm going spend some part of my vacation. And I
hate to admit it but I'm getting too _old_ to be rolling around in
fiberglass pulling wires for fun and no profit. I know, I should hire
an electrician but then I'll have to watch him.


Been there; done that - we're living in a house that once belonged to
a mechanical engineer who thought he could do everything - no surprise
that the ceramic tile isn't level (the easy swing of the trowel from
side to side and failure to use a level on each tile that leaves a
valley down the middle of the hall) plus some "How did he do that?"
electrical wiring.

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


To add onto to my previous post about multi-wire branch circuit I found
a Q&A related to a section of the code that relates to Device Removal.
In that answer, the code commentary mentions 4 wire circuits, so assuming
that I am extrapolating this correctly, a 3 breaker Edison circuit might be
a thing. On the other hand, I believe that standard 3 wire multi-branch
circuits require that the 2 hots be on opposite phases. I'm not sure how that
can be done with 3 breakers.

I'd sure like to hear from an electrician or electrical inspector on this one.
It looks like Greg Fretwell (electrical inspector down in Florida) still hangs
out in alt.home.repair. It might be worth checking this out with him.

Nice guy...talked me through installing a panel interlock and 30A inlet
so I can safely plug my portable generator directly into my house.

Anyway, here's that code snippet I mentioned. I only post it because
it mentions "3- or 4-wire circuits".

....Begin Included Snippet...

US NEC 300.13(B) Device Removal.
In multiwire branch circuits, the continuity of a grounded conductor shall
not depend on device connections such as lampholders, receptacles, and
so forth, where the removal of such devices would interrupt the continuity.

The code commentary on that notes:

Grounded conductors (neutrals) of multiwire branch circuits supplying
receptacles, lampholders, or other such devices are not permitted to
depend on terminal connections for continuity between devices.

For such installations (3- or 4-wire circuits), a splice is made and a
jumper is connected to the terminal, unless the neutral is looped;
that is, a receptacle or lampholder could be replaced without
interrupting the continuity of energized downstream line-to-neutral
loads (see commentary to 300.14).

Opening the neutral could cause unbalanced voltages, and a
considerably higher voltage would be impressed on one part
of a multiwire branch circuit, especially if the downstream
line-to-neutral loads were appreciably unbalanced.

This requirement does not apply to individual 2-wire circuits
or other circuits that do not contain a grounded (neutral) conductor.

....End Included Snippet...

On Sun, 21 Mar 2021 16:33:14 -0400, J. Clarke
wrote:

Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?

Every time someone tells me that wiring should be done by a
"professional" I run into another example of egregiously bad wiring
installed by a "professional".

Well, I know now how I'm going spend some part of my vacation. And I
hate to admit it but I'm getting too _old_ to be rolling around in
fiberglass pulling wires for fun and no profit. I know, I should hire
an electrician but then I'll have to watch him.

I'm with you there. I've seen stuff in relatively new houses that
looks like it was done by an absolute moron. Our downstairs bathroom
in our VT house (built in '87, we moved in, in '93) had a cheap
contractor's fixture above the vanity. SWMBO decided that a new light
was in order. I took the old one off and discovered that there was no
box behind it. In further inspection, I found that the romex came up
in the wrong wall box. Did they run another line down to the
unfinished basement? No. Did they notch the 2x4 to get the wire into
the right wall cavity? Nope. They notched the sheetrock and ran it
around the stud, then papered over it. Nice.

In our hose before that, there were no boxes behind outdoor fixtures
hanging on brick. Now what to do?

I'm sure it wasn't done by an electrician but a friends basement was
wired in zip cord.

I'm doing a *lot* of wiring in our basement and I'll guarantee that
it's done as well as any residential electrician would do.

On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

I don't see three.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

And his switch is in the neutral. That's enough to make your head
hurt.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.

I don't see how to do it with only one cable. Using two is _really_
scary.

On Sunday, March 21, 2021 at 8:22:14 PM UTC-4, wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.
I don't see three.
In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.
And his switch is in the neutral. That's enough to make your head
hurt.

Maybe. We're not there to check. The white wire can be used as a switch
leg but it's supposed to marked as hot. I'm not doubting that JC knows
what he's looking at cuz he's there, just saying that things are confusing
enough here that something else might be being missed.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.
4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

Southwire makes a 12/4 non-metallic cable and 14/4 MC. Both are standard sizes
for lighting circuits.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.

I don't see how to do it with only one cable. Using two is _really_
scary.

Again, 12/4 or 14/4 could be used. Yes, 2 cables would be scary, run-away scary.

However, I don't see how it doing it with 4 wire cable could be code considering
that 2 of the 3 hots would have to be on the same phase in a normal residential
situation. Bad! See my other post where a 4-wire multi-branch circuit is mentioned
in the NEC 300.13(B) commentary. 4-wire cable is apparently used in multi-branch
circuits, but it's certainly not something I've ever run across. I'm guessing it's only
used (properly) in a 480V 3 phase system.

And of course I'm not saying that this is what 100% what JC is dealing with, but
how else could a single fixture be interacting with 3 breakers? An actual voltage
reading with only one (or two?) breakers off might tell us something. I know that
the voltage will vary by what other loads are sharing the neutral when only one
breaker in a normal 3-wire multi-branch circuit is off. All JC's voltage sensor is
telling him is that some amount of voltage is present.

on Sun, 21 Mar 2021 20:22:06 -0400 typed in
rec.woodworking the following:

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

OTOH, "I have this wire, so I don't have to go buy 'new'."

--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

pyotr filipivich writes:
on Sun, 21 Mar 2021 20:22:06 -0400 typed in
rec.woodworking the following:

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

Technically, 12-3 w/g is a 'four-wire cable' and along with 14-3 w/g
is used heavily in lighting circuits; to wit, in three and four-way
switched circuits.

On Mon, 22 Mar 2021 08:28:17 -0700, pyotr filipivich
wrote:

on Sun, 21 Mar 2021 20:22:06 -0400 typed in
rec.woodworking the following:

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

OTOH, "I have this wire, so I don't have to go buy 'new'."

I'm pretty sure this wiring is all original to the house, which was
commercially built.

On Monday, March 22, 2021 at 1:22:37 PM UTC-4, J. Clarke wrote:
On Mon, 22 Mar 2021 08:28:17 -0700, pyotr filipivich
wrote:

on Sun, 21 Mar 2021 20:22:06 -0400 typed in
rec.woodworking the following:

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

OTOH, "I have this wire, so I don't have to go buy 'new'."

I'm pretty sure this wiring is all original to the house, which was
commercially built.

That doesn't negate OTOH, "I have this wire, so I don't have to go buy 'new'."

The original electrician may have had the 4-wire cable in his truck and used
it to save, or make up for lack of, 12/2 or 14/2 wire.

Multi-wire circuits can also be cheaper (less cable cost) and less labor (run one
14/3 cable instead of running two 14/2 cables).

As noted earlier: This is all speculation on my part.

On Sun, 21 Mar 2021 19:32:55 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 8:22:14 PM UTC-4, wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.
I don't see three.
In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.
And his switch is in the neutral. That's enough to make your head
hurt.

Maybe. We're not there to check. The white wire can be used as a switch
leg but it's supposed to marked as hot. I'm not doubting that JC knows
what he's looking at cuz he's there, just saying that things are confusing
enough here that something else might be being missed.

Sure, I do that all the time with 240 circuits - paint the white wire
with a red sharpie. I have sharpies in my electrical tool caddy for
that reason.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.
4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

Southwire makes a 12/4 non-metallic cable and 14/4 MC. Both are standard sizes
for lighting circuits.

It can't be something the average electrician would have on his truck.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.

I don't see how to do it with only one cable. Using two is _really_
scary.

Again, 12/4 or 14/4 could be used. Yes, 2 cables would be scary, run-away scary.

However, I don't see how it doing it with 4 wire cable could be code considering
that 2 of the 3 hots would have to be on the same phase in a normal residential
situation. Bad! See my other post where a 4-wire multi-branch circuit is mentioned
in the NEC 300.13(B) commentary. 4-wire cable is apparently used in multi-branch
circuits, but it's certainly not something I've ever run across. I'm guessing it's only
used (properly) in a 480V 3 phase system.

And of course I'm not saying that this is what 100% what JC is dealing with, but
how else could a single fixture be interacting with 3 breakers? An actual voltage
reading with only one (or two?) breakers off might tell us something. I know that
the voltage will vary by what other loads are sharing the neutral when only one
breaker in a normal 3-wire multi-branch circuit is off. All JC's voltage sensor is
telling him is that some amount of voltage is present.

On Mon, 22 Mar 2021 16:12:17 GMT, (Scott Lurndal)
wrote:

pyotr filipivich writes:
on Sun, 21 Mar 2021 20:22:06 -0400 typed in
rec.woodworking the following:

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

Technically, 12-3 w/g is a 'four-wire cable' and along with 14-3 w/g
is used heavily in lighting circuits; to wit, in three and four-way
switched circuits.

Doesn't all w/g cable have a bare copper wire as the ground, now? I
know it used to be green but I haven't seen that in forever. Sure, /3
is all over the place but /4 is a different animal, at least in
residential. Obviously it makes sense with 3-phase circuits.

On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.


Could only occur on a 3 phase circuit - and BY LAW all edison circuits
MUST use a "tied breaker" - and in a fused panel a "ganged pull-out"
which makes it IMPOSSIBLE to shut off power on one side only.

Using a "tracer" is fraught with possibilities - including "induced
cross-talk"
The REAL test is if the light functions with any ONE of the 3
circuits enabled singly - or only with one of the three. Are all of
the 3 on one side of the panel? If so check if all 3 neutrals are tied
together - in which case they may all be connected to each other, but
not properly connected to the incoming neutral

On Monday, March 22, 2021 at 4:47:22 PM UTC-4, wrote:
On Sun, 21 Mar 2021 19:32:55 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 8:22:14 PM UTC-4, wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.
I don't see three.
In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.
And his switch is in the neutral. That's enough to make your head
hurt.

Maybe. We're not there to check. The white wire can be used as a switch
leg but it's supposed to marked as hot. I'm not doubting that JC knows
what he's looking at cuz he's there, just saying that things are confusing
enough here that something else might be being missed.
Sure, I do that all the time with 240 circuits - paint the white wire
with a red sharpie. I have sharpies in my electrical tool caddy for
that reason.
If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.
4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

Southwire makes a 12/4 non-metallic cable and 14/4 MC. Both are standard sizes
for lighting circuits.
It can't be something the average electrician would have on his truck.

Obviously we're having a discussion about a bunch of unknowns here, but I think you'd
have to agree that that statement isn't particularly relevant.

Even if there was such a class of electricians known as "average" which would somehow
preclude them from having 12/4 on their truck, we have no idea what type of electrician
wired JC's house.

An electrician that worked for a company that wires everything from single family residential
homes to condos to multi-use commercial buildings could certainly have this type of wire on
their truck.

In another post, JC said that the house was "commercially built". Not quite sure what that
means or if it relates to the type of electrician that was involved.


I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.

I don't see how to do it with only one cable. Using two is _really_
scary.

Again, 12/4 or 14/4 could be used. Yes, 2 cables would be scary, run-away scary.

However, I don't see how it doing it with 4 wire cable could be code considering
that 2 of the 3 hots would have to be on the same phase in a normal residential
situation. Bad! See my other post where a 4-wire multi-branch circuit is mentioned
in the NEC 300.13(B) commentary. 4-wire cable is apparently used in multi-branch
circuits, but it's certainly not something I've ever run across. I'm guessing it's only
used (properly) in a 480V 3 phase system.

And of course I'm not saying that this is what 100% what JC is dealing with, but
how else could a single fixture be interacting with 3 breakers? An actual voltage
reading with only one (or two?) breakers off might tell us something. I know that
the voltage will vary by what other loads are sharing the neutral when only one
breaker in a normal 3-wire multi-branch circuit is off. All JC's voltage sensor is
telling him is that some amount of voltage is present.

On Sun, 21 Mar 2021 16:51:41 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit

Very common if wired with a "switch drop" -
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Again -not unusual
Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Notuncommon with a "fox and hound" transmitter - crosstalk between 2
adjacent cables shows up at 2 breakers - or 3 (or possibly even 4)
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

You finally found the REAL power source.

Replaced fixture, turned breakers back on, everything works, I didn't
die.
Did you turn them on one at a time and check to see when the light
camne on?? My bet is when you turned the first 2 on the light still
didn't light - and the third (REAL power source) breaker caused the
light to come on. Go back and try, then get back to us with your
results.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


To add onto to my previous post about multi-wire branch circuit I found
a Q&A related to a section of the code that relates to Device Removal.
In that answer, the code commentary mentions 4 wire circuits, so assuming
that I am extrapolating this correctly, a 3 breaker Edison circuit might be
a thing. On the other hand, I believe that standard 3 wire multi-branch
circuits require that the 2 hots be on opposite phases. I'm not sure how that
can be done with 3 breakers.

Only on 3 phase - where you get 110 and 208 instead of 110 and 220

I'd sure like to hear from an electrician or electrical inspector on this one.
It looks like Greg Fretwell (electrical inspector down in Florida) still hangs
out in alt.home.repair. It might be worth checking this out with him.

Nice guy...talked me through installing a panel interlock and 30A inlet
so I can safely plug my portable generator directly into my house.

Anyway, here's that code snippet I mentioned. I only post it because
it mentions "3- or 4-wire circuits".

...Begin Included Snippet...

US NEC 300.13(B) Device Removal.
In multiwire branch circuits, the continuity of a grounded conductor shall
not depend on device connections such as lampholders, receptacles, and
so forth, where the removal of such devices would interrupt the continuity.

The code commentary on that notes:

Grounded conductors (neutrals) of multiwire branch circuits supplying
receptacles, lampholders, or other such devices are not permitted to
depend on terminal connections for continuity between devices.

For such installations (3- or 4-wire circuits), a splice is made and a
jumper is connected to the terminal, unless the neutral is looped;
that is, a receptacle or lampholder could be replaced without
interrupting the continuity of energized downstream line-to-neutral
loads (see commentary to 300.14).

Opening the neutral could cause unbalanced voltages, and a
considerably higher voltage would be impressed on one part
of a multiwire branch circuit, especially if the downstream
line-to-neutral loads were appreciably unbalanced.

This requirement does not apply to individual 2-wire circuits
or other circuits that do not contain a grounded (neutral) conductor.

...End Included Snippet...

On Monday, March 22, 2021 at 5:53:13 PM UTC-4, Clare Snyder wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:
On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.


Could only occur on a 3 phase circuit - and BY LAW all edison circuits
MUST use a "tied breaker" - and in a fused panel a "ganged pull-out"
which makes it IMPOSSIBLE to shut off power on one side only.

By *law* or by *code*?

I did mention both code & 3 phase circuits earlier. Of course, we don't know
if code was followed.


Using a "tracer" is fraught with possibilities - including "induced
cross-talk"

As noted earlier, a meter reading would certainly tell us more.

The REAL test is if the light functions with any ONE of the 3
circuits enabled singly - or only with one of the three. Are all of
the 3 on one side of the panel? If so check if all 3 neutrals are tied
together - in which case they may all be connected to each other, but
not properly connected to the incoming neutral

He also should confirm that the neutral is actually switched or if it's just a
unmarked white conductor used as part of a switch leg. Unmarked would
be a code violation, at least in the US.

On Mon, 22 Mar 2021 18:04:29 -0400, Clare Snyder
wrote:

On Sun, 21 Mar 2021 16:51:41 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit

Very common if wired with a "switch drop" -
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Again -not unusual
Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Notuncommon with a "fox and hound" transmitter - crosstalk between 2
adjacent cables shows up at 2 breakers - or 3 (or possibly even 4)
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

You finally found the REAL power source.

Replaced fixture, turned breakers back on, everything works, I didn't
die.
Did you turn them on one at a time and check to see when the light
camne on?? My bet is when you turned the first 2 on the light still
didn't light - and the third (REAL power source) breaker caused the
light to come on. Go back and try, then get back to us with your
results.

It's a 3 way. Have to turn two breakers off with the switch in one
position before the light goes out. If I flip the switch, then I have
to turn the third breaker off to make it go out. I didn't try
multiple combinations of breakers and switch positions--the light is
up two flights of stairs from the breaker panel.

Putting the basement lights on their own circuit is another project
that I guess I should handle while cleaning up this mess.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


To add onto to my previous post about multi-wire branch circuit I found
a Q&A related to a section of the code that relates to Device Removal.
In that answer, the code commentary mentions 4 wire circuits, so assuming
that I am extrapolating this correctly, a 3 breaker Edison circuit might be
a thing. On the other hand, I believe that standard 3 wire multi-branch
circuits require that the 2 hots be on opposite phases. I'm not sure how that
can be done with 3 breakers.

Only on 3 phase - where you get 110 and 208 instead of 110 and 220

I'd sure like to hear from an electrician or electrical inspector on this one.
It looks like Greg Fretwell (electrical inspector down in Florida) still hangs
out in alt.home.repair. It might be worth checking this out with him.

Nice guy...talked me through installing a panel interlock and 30A inlet
so I can safely plug my portable generator directly into my house.

Anyway, here's that code snippet I mentioned. I only post it because
it mentions "3- or 4-wire circuits".

...Begin Included Snippet...

US NEC 300.13(B) Device Removal.
In multiwire branch circuits, the continuity of a grounded conductor shall
not depend on device connections such as lampholders, receptacles, and
so forth, where the removal of such devices would interrupt the continuity.

The code commentary on that notes:

Grounded conductors (neutrals) of multiwire branch circuits supplying
receptacles, lampholders, or other such devices are not permitted to
depend on terminal connections for continuity between devices.

For such installations (3- or 4-wire circuits), a splice is made and a
jumper is connected to the terminal, unless the neutral is looped;
that is, a receptacle or lampholder could be replaced without
interrupting the continuity of energized downstream line-to-neutral
loads (see commentary to 300.14).

Opening the neutral could cause unbalanced voltages, and a
considerably higher voltage would be impressed on one part
of a multiwire branch circuit, especially if the downstream
line-to-neutral loads were appreciably unbalanced.

This requirement does not apply to individual 2-wire circuits
or other circuits that do not contain a grounded (neutral) conductor.

...End Included Snippet...

On Mon, 22 Mar 2021 14:58:45 -0700 (PDT), DerbyDad03
wrote:

On Monday, March 22, 2021 at 4:47:22 PM UTC-4, wrote:
On Sun, 21 Mar 2021 19:32:55 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 8:22:14 PM UTC-4, wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.
I don't see three.
In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.
And his switch is in the neutral. That's enough to make your head
hurt.

Maybe. We're not there to check. The white wire can be used as a switch
leg but it's supposed to marked as hot. I'm not doubting that JC knows
what he's looking at cuz he's there, just saying that things are confusing
enough here that something else might be being missed.
Sure, I do that all the time with 240 circuits - paint the white wire
with a red sharpie. I have sharpies in my electrical tool caddy for
that reason.
If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.
4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

Southwire makes a 12/4 non-metallic cable and 14/4 MC. Both are standard sizes
for lighting circuits.
It can't be something the average electrician would have on his truck.

Obviously we're having a discussion about a bunch of unknowns here, but I think you'd
have to agree that that statement isn't particularly relevant.

I think it is. I'd have to guess that the moron who did this didn't
plan it in advance.

Even if there was such a class of electricians known as "average" which would somehow
preclude them from having 12/4 on their truck, we have no idea what type of electrician
wired JC's house.

Residential, I would assume. At least the industrial/commercial
electricians I know don't work residential and certainly wouldn't put
together an abortion like that.

An electrician that worked for a company that wires everything from single family residential
homes to condos to multi-use commercial buildings could certainly have this type of wire on
their truck.

I don't know any of those. It's a different class of electrician,
IME. Maybe someone moonlighting but that doesn't fit with a
"commercially built house".

In another post, JC said that the house was "commercially built". Not quite sure what that
means or if it relates to the type of electrician that was involved.

I assumed he meant that it wasn't made by a homeowner but he can speak
for himself.

On Mon, 22 Mar 2021 15:17:09 -0700 (PDT), DerbyDad03
wrote:

On Monday, March 22, 2021 at 5:53:13 PM UTC-4, Clare Snyder wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:
On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.


Could only occur on a 3 phase circuit - and BY LAW all edison circuits
MUST use a "tied breaker" - and in a fused panel a "ganged pull-out"
which makes it IMPOSSIBLE to shut off power on one side only.

By *law* or by *code*?

They're the same in many/most jurisdictions. The NEC is written into
the law.

I did mention both code & 3 phase circuits earlier. Of course, we don't know
if code was followed.


Using a "tracer" is fraught with possibilities - including "induced
cross-talk"

As noted earlier, a meter reading would certainly tell us more.

Only if done right. I know many who've made that mistake.

The REAL test is if the light functions with any ONE of the 3
circuits enabled singly - or only with one of the three. Are all of
the 3 on one side of the panel? If so check if all 3 neutrals are tied
together - in which case they may all be connected to each other, but
not properly connected to the incoming neutral

He also should confirm that the neutral is actually switched or if it's just a
unmarked white conductor used as part of a switch leg. Unmarked would
be a code violation, at least in the US.

On Monday, March 22, 2021 at 9:41:02 PM UTC-4, wrote:
On Mon, 22 Mar 2021 14:58:45 -0700 (PDT), DerbyDad03
wrote:

On Monday, March 22, 2021 at 4:47:22 PM UTC-4, wrote:
On Sun, 21 Mar 2021 19:32:55 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 8:22:14 PM UTC-4, wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos..

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.
I don't see three.
In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.
And his switch is in the neutral. That's enough to make your head
hurt.

Maybe. We're not there to check. The white wire can be used as a switch
leg but it's supposed to marked as hot. I'm not doubting that JC knows
what he's looking at cuz he's there, just saying that things are confusing
enough here that something else might be being missed.
Sure, I do that all the time with 240 circuits - paint the white wire
with a red sharpie. I have sharpies in my electrical tool caddy for
that reason.
If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.
4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

Southwire makes a 12/4 non-metallic cable and 14/4 MC. Both are standard sizes
for lighting circuits.
It can't be something the average electrician would have on his truck.

Obviously we're having a discussion about a bunch of unknowns here, but I think you'd
have to agree that that statement isn't particularly relevant.
I think it is. I'd have to guess that the moron who did this didn't
plan it in advance.
Even if there was such a class of electricians known as "average" which would somehow
preclude them from having 12/4 on their truck, we have no idea what type of electrician
wired JC's house.
Residential, I would assume. At least the industrial/commercial
electricians I know don't work residential and certainly wouldn't put
together an abortion like that.

I *know* that you aren't so naïve to think that there aren't hacks at every level.

An electrician that worked for a company that wires everything from single family residential
homes to condos to multi-use commercial buildings could certainly have this type of wire on
their truck.
I don't know any of those. It's a different class of electrician,
IME. Maybe someone moonlighting but that doesn't fit with a
"commercially built house".

Again, we don't know who did the wiring at JC place, but it only took
one simple search in a city that I picked at random to almost instantly
find a company that does both residential and commercial work.

I'll bet you'll find some in your city too.

https://mccollelectricco.com/

In another post, JC said that the house was "commercially built". Not quite sure what that
means or if it relates to the type of electrician that was involved.
I assumed he meant that it wasn't made by a homeowner but he can speak
for himself.

On Monday, March 22, 2021 at 9:43:51 PM UTC-4, wrote:
On Mon, 22 Mar 2021 15:17:09 -0700 (PDT), DerbyDad03
wrote:

On Monday, March 22, 2021 at 5:53:13 PM UTC-4, Clare Snyder wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:
On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.


Could only occur on a 3 phase circuit - and BY LAW all edison circuits
MUST use a "tied breaker" - and in a fused panel a "ganged pull-out"
which makes it IMPOSSIBLE to shut off power on one side only.

By *law* or by *code*?
They're the same in many/most jurisdictions. The NEC is written into
the law.

I'll agree that many jurisdictions *mandate* that the NEC be followed, but
that doesn't make the NEC itself a law, under the legal definition of a law.

When an amendment or clarification or even a whole new version comes out,
these jurisdictions aren't running it through their legislatures for approval.

I'm pretty sure that no one ever challenged the NEC in their state's Supreme Court. ;-)

I did mention both code & 3 phase circuits earlier. Of course, we don't know
if code was followed.


Using a "tracer" is fraught with possibilities - including "induced
cross-talk"

As noted earlier, a meter reading would certainly tell us more.
Only if done right. I know many who've made that mistake.
The REAL test is if the light functions with any ONE of the 3
circuits enabled singly - or only with one of the three. Are all of
the 3 on one side of the panel? If so check if all 3 neutrals are tied
together - in which case they may all be connected to each other, but
not properly connected to the incoming neutral

He also should confirm that the neutral is actually switched or if it's just a
unmarked white conductor used as part of a switch leg. Unmarked would
be a code violation, at least in the US.

DerbyDad03 on Mon, 22 Mar 2021 13:24:49 -0700
(PDT) typed in rec.woodworking the following:
On Monday, March 22, 2021 at 1:22:37 PM UTC-4, J. Clarke wrote:
On Mon, 22 Mar 2021 08:28:17 -0700, pyotr filipivich
wrote:

on Sun, 21 Mar 2021 20:22:06 -0400 typed in
rec.woodworking the following:

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

OTOH, "I have this wire, so I don't have to go buy 'new'."

I'm pretty sure this wiring is all original to the house, which was
commercially built.

That doesn't negate OTOH, "I have this wire, so I don't have to go buy 'new'."

Ayup. The sort of thing which appeals to guys trying to stay
under budget, be they DIY or Professional DIY.

--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

DerbyDad03 on Mon, 22 Mar 2021 15:17:09 -0700
(PDT) typed in rec.woodworking the following:

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.


Could only occur on a 3 phase circuit - and BY LAW all edison circuits
MUST use a "tied breaker" - and in a fused panel a "ganged pull-out"
which makes it IMPOSSIBLE to shut off power on one side only.

By *law* or by *code*?

I did mention both code & 3 phase circuits earlier. Of course, we don't know
if code was followed.

And that there is the kicker. Doesn't matter what the standard
is, if there was a standard, "it worked" and got "signed off".
--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

J. Clarke on Mon, 22 Mar 2021 18:20:41
-0400 typed in rec.woodworking the following:

Again -not unusual
Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Notuncommon with a "fox and hound" transmitter - crosstalk between 2
adjacent cables shows up at 2 breakers - or 3 (or possibly even 4)
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

You finally found the REAL power source.

Replaced fixture, turned breakers back on, everything works, I didn't
die.
Did you turn them on one at a time and check to see when the light
camne on?? My bet is when you turned the first 2 on the light still
didn't light - and the third (REAL power source) breaker caused the
light to come on. Go back and try, then get back to us with your
results.

It's a 3 way. Have to turn two breakers off with the switch in one
position before the light goes out. If I flip the switch, then I have
to turn the third breaker off to make it go out. I didn't try
multiple combinations of breakers and switch positions--the light is
up two flights of stairs from the breaker panel.

Putting the basement lights on their own circuit is another project
that I guess I should handle while cleaning up this mess.

This is sounding like one of Those Projects. Where it turns out
the easiest way to have solved it was to have taken the old bulb and
put it in a new house.
--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

J. Clarke on Mon, 22 Mar 2021 13:22:34
-0400 typed in rec.woodworking the following:
On Mon, 22 Mar 2021 08:28:17 -0700, pyotr filipivich
wrote:

on Sun, 21 Mar 2021 20:22:06 -0400 typed in
rec.woodworking the following:

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

OTOH, "I have this wire, so I don't have to go buy 'new'."

I'm pretty sure this wiring is all original to the house, which was
commercially built.

Come to B.A.R.F. Construction - We'll throw it up!

--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

On Mon, 22 Mar 2021 19:36:44 -0700, pyotr filipivich
wrote:

J. Clarke on Mon, 22 Mar 2021 13:22:34
-0400 typed in rec.woodworking the following:
On Mon, 22 Mar 2021 08:28:17 -0700, pyotr filipivich
wrote:

on Sun, 21 Mar 2021 20:22:06 -0400 typed in
rec.woodworking the following:

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

OTOH, "I have this wire, so I don't have to go buy 'new'."

I'm pretty sure this wiring is all original to the house, which was
commercially built.

Come to B.A.R.F. Construction - We'll throw it up!

That's pretty much it. The guy built half the town, to the lowest
price he could manage.

On Mon, 22 Mar 2021 19:36:44 -0700, pyotr filipivich
wrote:

J. Clarke on Mon, 22 Mar 2021 18:20:41
-0400 typed in rec.woodworking the following:

Again -not unusual
Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Notuncommon with a "fox and hound" transmitter - crosstalk between 2
adjacent cables shows up at 2 breakers - or 3 (or possibly even 4)
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

You finally found the REAL power source.

Replaced fixture, turned breakers back on, everything works, I didn't
die.
Did you turn them on one at a time and check to see when the light
camne on?? My bet is when you turned the first 2 on the light still
didn't light - and the third (REAL power source) breaker caused the
light to come on. Go back and try, then get back to us with your
results.

It's a 3 way. Have to turn two breakers off with the switch in one
position before the light goes out. If I flip the switch, then I have
to turn the third breaker off to make it go out. I didn't try
multiple combinations of breakers and switch positions--the light is
up two flights of stairs from the breaker panel.

Putting the basement lights on their own circuit is another project
that I guess I should handle while cleaning up this mess.

This is sounding like one of Those Projects. Where it turns out
the easiest way to have solved it was to have taken the old bulb and
put it in a new house.

There are times when I think that my next improvement on this house
will involve a bulldozer.

On 3/21/2021 4:33 PM, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?

Every time someone tells me that wiring should be done by a
"professional" I run into another example of egregiously bad wiring
installed by a "professional".

Well, I know now how I'm going spend some part of my vacation. And I
hate to admit it but I'm getting too _old_ to be rolling around in
fiberglass pulling wires for fun and no profit. I know, I should hire
an electrician but then I'll have to watch him.



I had a similar issue that I traced to a poorly grounded connection
inside of a metal junction box in my basement ceiling... someone thought
it was a good idea to put two separate circuits into this same junction
box, practically touching, wrapped loosely in electrical tape... who
needs wire nuts? No splicing tape and solder? Electric tape to the
rescue... haha. It was causing like a 40 volt leak onto another circuit.

On 3/21/2021 7:22 PM, DerbyDad03 wrote:
On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.




Sorry to butt in - but question. I have an Edison circuit (never knew
that was the name - having trouble finding info on-line) ... 2 K&T wires
running into a 120 year old ceramic fuse box - 2 hot shared neutral.

Someone told me that I need to have the two hots skip a breaker on the
same side so they are on the same phase - because if I use two phases it
can risk lighting up my wiring to 240V if a connection is broken.

Another person told me no, I need to have both hots on touching breakers
- opposing phases - because if I don't I can theoretically overload the
neutral line up to 30 AMP if the both circuits are loaded.

Do you have a suggestion as to which is safer? I won't run anything
more power-hungry than a fan, phone charger, or lamp on either of these
circuits. Certainly no heaters or A/C units. Everything else stays off
if I run the vacuum. Thanks!

On Tue, 23 Mar 2021 00:42:49 -0400, Michael Trew
wrote:

On 3/21/2021 7:22 PM, DerbyDad03 wrote:
On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.




Sorry to butt in - but question. I have an Edison circuit (never knew
that was the name - having trouble finding info on-line) ... 2 K&T wires
running into a 120 year old ceramic fuse box - 2 hot shared neutral.

Someone told me that I need to have the two hots skip a breaker on the
same side so they are on the same phase - because if I use two phases it
can risk lighting up my wiring to 240V if a connection is broken.

Another person told me no, I need to have both hots on touching breakers
- opposing phases - because if I don't I can theoretically overload the
neutral line up to 30 AMP if the both circuits are loaded.

Do you have a suggestion as to which is safer? I won't run anything
more power-hungry than a fan, phone charger, or lamp on either of these
circuits. Certainly no heaters or A/C units. Everything else stays off
if I run the vacuum. Thanks!

Code says different phases for the two hots. Should be both wired to
a single duplex breaker with the handles pinned so that both open and
close at the same time.

writes:
On Mon, 22 Mar 2021 15:17:09 -0700 (PDT), DerbyDad03
wrote:

Using a "tracer" is fraught with possibilities - including "induced
cross-talk"

As noted earlier, a meter reading would certainly tell us more.

Only if done right. I know many who've made that mistake.

Indeed. If, for example, your meter showed 34vac at the
light socket when the 3-way switched circuit was switched off, what would
your diagnosis be?

Michael Trew writes:
On 3/21/2021 7:22 PM, DerbyDad03 wrote:

Another person told me no, I need to have both hots on touching breakers
- opposing phases - because if I don't I can theoretically overload the
neutral line up to 30 AMP if the both circuits are loaded.

This. If they're on opposite phases, the current in the grounded
conductor (aka neutral) approaches zero as the load on each leg
approaches capacity.

If they're on the same phase, the current through the grounded
conductor may be 2x the circuit ampacity.

J. Clarke on Mon, 22 Mar 2021 23:46:47
-0400 typed in rec.woodworking the following:
On Mon, 22 Mar 2021 19:36:44 -0700, pyotr filipivich
wrote:

J. Clarke on Mon, 22 Mar 2021 18:20:41
-0400 typed in rec.woodworking the following:

Again -not unusual
Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Notuncommon with a "fox and hound" transmitter - crosstalk between 2
adjacent cables shows up at 2 breakers - or 3 (or possibly even 4)
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

You finally found the REAL power source.

Replaced fixture, turned breakers back on, everything works, I didn't
die.
Did you turn them on one at a time and check to see when the light
camne on?? My bet is when you turned the first 2 on the light still
didn't light - and the third (REAL power source) breaker caused the
light to come on. Go back and try, then get back to us with your
results.

It's a 3 way. Have to turn two breakers off with the switch in one
position before the light goes out. If I flip the switch, then I have
to turn the third breaker off to make it go out. I didn't try
multiple combinations of breakers and switch positions--the light is
up two flights of stairs from the breaker panel.

Putting the basement lights on their own circuit is another project
that I guess I should handle while cleaning up this mess.

This is sounding like one of Those Projects. Where it turns out
the easiest way to have solved it was to have taken the old bulb and
put it in a new house.

There are times when I think that my next improvement on this house
will involve a bulldozer.

"It's just Engineering." Which is another way of saying "it's just
money."

As my boss used to say "If you haven't got time to do it right,
when will you have time to do it over?"
--
pyotr filipivich
This Week's Panel: Us & Them - Eliminating Them.
Next Month's Panel: Having eliminated the old Them(tm)
Selecting who insufficiently Woke(tm) as to serve as the new Them(tm)

On Mon, 22 Mar 2021 18:54:50 -0700 (PDT), DerbyDad03
wrote:

On Monday, March 22, 2021 at 9:41:02 PM UTC-4, wrote:
On Mon, 22 Mar 2021 14:58:45 -0700 (PDT), DerbyDad03
wrote:

On Monday, March 22, 2021 at 4:47:22 PM UTC-4, wrote:
On Sun, 21 Mar 2021 19:32:55 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 8:22:14 PM UTC-4, wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:

On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.
I don't see three.
In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.
And his switch is in the neutral. That's enough to make your head
hurt.

Maybe. We're not there to check. The white wire can be used as a switch
leg but it's supposed to marked as hot. I'm not doubting that JC knows
what he's looking at cuz he's there, just saying that things are confusing
enough here that something else might be being missed.
Sure, I do that all the time with 240 circuits - paint the white wire
with a red sharpie. I have sharpies in my electrical tool caddy for
that reason.
If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.
4-wire cable? It's used in dryer cables but it's a lot larger than
what you'd find in a lighting circuit.

Southwire makes a 12/4 non-metallic cable and 14/4 MC. Both are standard sizes
for lighting circuits.
It can't be something the average electrician would have on his truck.

Obviously we're having a discussion about a bunch of unknowns here, but I think you'd
have to agree that that statement isn't particularly relevant.
I think it is. I'd have to guess that the moron who did this didn't
plan it in advance.
Even if there was such a class of electricians known as "average" which would somehow
preclude them from having 12/4 on their truck, we have no idea what type of electrician
wired JC's house.
Residential, I would assume. At least the industrial/commercial
electricians I know don't work residential and certainly wouldn't put
together an abortion like that.

I *know* that you aren't so naïve to think that there aren't hacks at every level.

I don't see that much crossover. Residential and commercial work are
significantly different with different people (union vs. non-union,
for example). Hacks, yes, but the issue is having an unusual cable
on-site when doing residential work and even the thought to do
something asinine like this.

An electrician that worked for a company that wires everything from single family residential
homes to condos to multi-use commercial buildings could certainly have this type of wire on
their truck.
I don't know any of those. It's a different class of electrician,
IME. Maybe someone moonlighting but that doesn't fit with a
"commercially built house".

Again, we don't know who did the wiring at JC place, but it only took
one simple search in a city that I picked at random to almost instantly
find a company that does both residential and commercial work.

With the same people?fm I know a business (not electrical) who
advertises related but targeted at both.

I'll bet you'll find some in your city too.

https://mccollelectricco.com/

In another post, JC said that the house was "commercially built". Not quite sure what that
means or if it relates to the type of electrician that was involved.
I assumed he meant that it wasn't made by a homeowner but he can speak
for himself.

On Mon, 22 Mar 2021 19:09:28 -0700 (PDT), DerbyDad03
wrote:

On Monday, March 22, 2021 at 9:43:51 PM UTC-4, wrote:
On Mon, 22 Mar 2021 15:17:09 -0700 (PDT), DerbyDad03
wrote:

On Monday, March 22, 2021 at 5:53:13 PM UTC-4, Clare Snyder wrote:
On Sun, 21 Mar 2021 16:22:03 -0700 (PDT), DerbyDad03
wrote:
On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.


Could only occur on a 3 phase circuit - and BY LAW all edison circuits
MUST use a "tied breaker" - and in a fused panel a "ganged pull-out"
which makes it IMPOSSIBLE to shut off power on one side only.

By *law* or by *code*?
They're the same in many/most jurisdictions. The NEC is written into
the law.

I'll agree that many jurisdictions *mandate* that the NEC be followed, but
that doesn't make the NEC itself a law, under the legal definition of a law.

No, it *is* law, with all of the responsibilities and penalties of any
similar law.

When an amendment or clarification or even a whole new version comes out,
these jurisdictions aren't running it through their legislatures for approval.

Nope. The *LAW* delegates that to the NFPA. The law incorporates the
NEC (and NFC) as law.

I'm pretty sure that no one ever challenged the NEC in their state's Supreme Court. ;-)

It would stand as much as any other regulation (law). There are far
more such regulations than there are laws and all have the force of
law. In fact, it's damned rare that legislatures pass laws anymore,
other than to give powers to administrative departments.

...

On Tue, 23 Mar 2021 14:26:38 GMT, (Scott Lurndal)
wrote:

writes:
On Mon, 22 Mar 2021 15:17:09 -0700 (PDT), DerbyDad03
wrote:

Using a "tracer" is fraught with possibilities - including "induced
cross-talk"

As noted earlier, a meter reading would certainly tell us more.

Only if done right. I know many who've made that mistake.

Indeed. If, for example, your meter showed 34vac at the
light socket when the 3-way switched circuit was switched off, what would
your diagnosis be?

An inactive runner, capacitance from the hot runner, and a
high-impedance meter.

On Mon, 22 Mar 2021 19:36:44 -0700, pyotr filipivich
wrote:

J. Clarke on Mon, 22 Mar 2021 18:20:41
-0400 typed in rec.woodworking the following:

Again -not unusual
Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Notuncommon with a "fox and hound" transmitter - crosstalk between 2
adjacent cables shows up at 2 breakers - or 3 (or possibly even 4)
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

You finally found the REAL power source.

Replaced fixture, turned breakers back on, everything works, I didn't
die.
Did you turn them on one at a time and check to see when the light
camne on?? My bet is when you turned the first 2 on the light still
didn't light - and the third (REAL power source) breaker caused the
light to come on. Go back and try, then get back to us with your
results.

It's a 3 way. Have to turn two breakers off with the switch in one
position before the light goes out. If I flip the switch, then I have
to turn the third breaker off to make it go out. I didn't try
multiple combinations of breakers and switch positions--the light is
up two flights of stairs from the breaker panel.

Putting the basement lights on their own circuit is another project
that I guess I should handle while cleaning up this mess.

This is sounding like one of Those Projects. Where it turns out
the easiest way to have solved it was to have taken the old bulb and
put it in a new house.

He's doing a house-transplant.

In rec.woodworking, pyotr filipivich wrote:
This is sounding like one of Those Projects. Where it turns out
the easiest way to have solved it was to have taken the old bulb and
put it in a new house.

In computers there's a term "yak shaving" for trying to solve one simple
problem and getting diverted into a trail of fixing many other problems
uncovered in the process. The term comes from "Ren and Stimpy", but I
haven't seen enough of that to know more.

The TV show "Malcolm in the Middle" has a good example, also from
changing a light bulb:

https://www.youtube.com/watch?v=AbSehcT19u0

Elijah
------
no one wants to shave the yak but then you find you need to for reason X

On 3/23/2021 8:34 AM, J. Clarke wrote:
On Tue, 23 Mar 2021 00:42:49 -0400, Michael
wrote:

On 3/21/2021 7:22 PM, DerbyDad03 wrote:
On Sunday, March 21, 2021 at 4:33:18 PM UTC-4, J. Clarke wrote:
Please forgive me--this is a bit of a rant.

I went to put a new fixture at the top of the stairs--the old one is
physically too small to hold anything bigger than a 60w incandescent
(by physically I mean you can't put the globe on if anything bigger is
in it, and that includes CF and LED that are larger than 60W
equivalent and in that location a 60 just isn't enough light.

Well, went to kill the power to the circuit and discovered chaos.

First:
Turned the switch off
Checked socket with a voltage sensor
Still voltage on the circuit
Par for the course in this house
Switch is in the neutral leg
Add to list of stuff to fix.

Next:
Screwed adapter into socket and plugged in tracer
Traced signal in breaker panel
Not one, but _two_ breakers showed signal
Turned both off
Went back upstairs
Checked for voltage again
No voltage--good
Flipped switch--checked again
Voltage--not good
Back to the panel
Identify third breaker, turn off
Now no voltage

Replaced fixture, turned breakers back on, everything works, I didn't
die.

But now I have the real mystery--how is this effing light managing to
be connected to not one, but _three_ separate branch circuits?


It's possible that you are dealing with an Edison circuit, also known as
a "shared neutral" or "multi-wire branch circuit". Granted, Edison circuits
usually only involve 2 breakers, but I think I could imagine one with 3.

In a typical Edison circuit a cable with 2 hots and a single neutral has the
2 hots tied to separate breakers. That 3 wire cable runs to a junction box
from which a pair of 2-wire (hot and neutral) cables emerge. Those 2 circuits
share the single source neutral from the 3 wire cable.

If you only turn off one breaker, you will often get some voltage that bleeds
back through the neutral at the supposed-to-be-dead fixture. If you used a
meter as opposed to a voltage sensor, I'll bet that it's not the full 120 VAC.

Now - although this is not something that I have ever seen - expand that to
a 4 wire source cable (3 hots and a single neutral) to the first junction box
and you've brought that 3rd breaker into the picture.

I don't know if a "super-Edison" (I made that up) would be allowed by code,
but I can certainly imagine someone grabbing some 12/4 Romex and running
one.




Sorry to butt in - but question. I have an Edison circuit (never knew
that was the name - having trouble finding info on-line) ... 2 K&T wires
running into a 120 year old ceramic fuse box - 2 hot shared neutral.

Someone told me that I need to have the two hots skip a breaker on the
same side so they are on the same phase - because if I use two phases it
can risk lighting up my wiring to 240V if a connection is broken.

Another person told me no, I need to have both hots on touching breakers
- opposing phases - because if I don't I can theoretically overload the
neutral line up to 30 AMP if the both circuits are loaded.

Do you have a suggestion as to which is safer? I won't run anything
more power-hungry than a fan, phone charger, or lamp on either of these
circuits. Certainly no heaters or A/C units. Everything else stays off
if I run the vacuum. Thanks!

Code says different phases for the two hots. Should be both wired to
a single duplex breaker with the handles pinned so that both open and
close at the same time.



Thanks! I've had them on the same phase for years... oops. I suppose I
best go fix that, and look for a duplex breaker. I really ought to run
a few Romex lines up from the breaker box and pull that ceramic fuse box.