Subject: Re: [Shop-talk] Strange electrical house issues

From: Brian Kemp <[email-masked]>
Date: Sun, 24 Mar 2013 13:52:50 -0700

Jim - It sounds like a circuit diagram is necessary to find out what 
wire is doing what.

Some ideas to help (remembering that electricity is dangerous and you 
need to use appropriate caution):

- Make a diagram of the outlet including each connection so you can 
always put it back together the old way

- Turn off the circuit and disconnect each wire.  Verify each wire has 
no power.  A non-contact voltage tester is helpful.  Put a wire nut on 
each bare end for safety.

- Turn the power back on and see which wire is the hot supply.  If that 
is the two wire cable, you found your neutral, which should be the other 
wire in the pair.  If it is the three wire cable (black or red), that 
white wire is probably your neutral and the other wire (red or black) 
may be a second hot wire on another circuit.

- You already figured out some of the outlets after this on in the 
circuit.  I'd go to the next closest outlet and make the same diagram in 
that outlet.  Hopefully, it will make more sense with a single pair in 
and out.  With the power off and verified with a voltage tester, put a 
continuity checker on the wire pair in one outlet box and touch the 
wires in the second box to verify you have the wire pair identified. 
This process should help further figure out the wiring in the home.

Other things that may help:

- disconnected wires, such as when the circuit breaker is off or when 
the neutral is disconnected my indicate an odd voltage with a digital 
volt meter.  Put a load on the wires and the voltage will go to near 
zero.  I used a lamp socket with a light bulb.

- if you have metal boxes, they may be wired with a ground wire 
independent of the electrical supply wires.  This was the case in my my 
first and my current houses.

- three conductor wire may have been used to run two circuits with a 
single wire pair.  Two hots share a neutral.  I don't think this is code 
anymore and don't recommend it.  Part of the theory is that if they are 
out a phase (different lines of the 220 supply), the single neutral can 
handle it.

- The red may be a switched circuit, where perhaps there was a wall 
switch that controlled the outlet.  If you have any wall switches, check 
them and see if they come into play in your circuit diagram. At some 
point, an overhead light may have been connected to the wall switch and 
the old wires to the outlet were just left behind.

- Some electricians follow a pattern on supply into the top of the box 
and next outlet out the bottom of the box (I may have that backwards) 
for wall outlets, so if you are mapping multiple outlets, that may make 
things easier.

Good luck with the project.  Taking the time to do the full circuit 
diagram in my 1950 built house was critical to understanding the 
problems I was having and figuring out a way to fix issues, such as 
every outlet but one in the original portion of the house including the 
refrigerator on the same circuit.  I ended up rewiring all those outlets 
into four circuits and ended the common computer lockups or beeping UPS 
warnings.

Brian

On 3/24/2013 8:50 AM, Jim and Kathy wrote:
> I have a very strange electrical problem at my vacation home and am hoping
> someone here has an idea of what could be going on.
_______________________________________________

[email-masked]
Archive: http://www.team.net/archive

---

From: Jim Stone <[email-masked]>
Date: Sun, 24 Mar 2013 18:04:44 -0400

Thanks guys. I had to leave the house right after posting this but I will
spend more time on it tomorrow and report back. The 'switched outlet' might be
a winner, as a ceiling fan was added to the room at one point and there are
two separate light switches, one for the fan and one for the light.
The thing that confuses me (besides the white/black part) is the fact that
both the red and white were hot. Wiring them together should have produced 240
volts and fried something, unless they were somehow now redundant and both
connected to the same circuit.
More to follow, I'm an sure!
Jim

Sent from my iPhone

On Mar 24, 2013, at 4:53 PM, "Brian Kemp" <[email-masked]> wrote:

> Jim - It sounds like a circuit diagram is necessary to find out what wire is
doing what.
>
> Some ideas to help (remembering that electricity is dangerous and you need
to use appropriate caution):
>
> - Make a diagram of the outlet including each connection so you can always
put it back together the old way
>
> - Turn off the circuit and disconnect each wire.  Verify each wire has no
power.  A non-contact voltage tester is helpful.  Put a wire nut on each bare
end for safety.
>
> - Turn the power back on and see which wire is the hot supply.  If that is
the two wire cable, you found your neutral, which should be the other wire in
the pair.  If it is the three wire cable (black or red), that white wire is
probably your neutral and the other wire (red or black) may be a second hot
wire on another circuit.
>
> - You already figured out some of the outlets after this on in the circuit.
I'd go to the next closest outlet and make the same diagram in that outlet.
Hopefully, it will make more sense with a single pair in and out.  With the
power off and verified with a voltage tester, put a continuity checker on the
wire pair in one outlet box and touch the wires in the second box to verify
you have the wire pair identified. This process should help further figure out
the wiring in the home.
> - disconnected wires, such as when the circuit breaker is off or when the
neutral is disconnected my indicate an odd voltage with a digital volt meter.
Put a load on the wires and the voltage will go to near zero.  I used a lamp
socket with a light bulb.
>
> - if you have metal boxes, they may be wired with a ground wire independent
of the electrical supply wires.  This was the case in my my first and my
current houses.
>
> - three conductor wire may have been used to run two circuits with a single
wire pair.  Two hots share a neutral.  I don't think this is code anymore and
don't recommend it.  Part of the theory is that if they are out a phase
(different lines of the 220 supply), the single neutral can handle it.
>
> - The red may be a switched circuit, where perhaps there was a wall switch
that controlled the outlet.  If you have any wall switches, check them and see
if they come into play in your circuit diagram. At some point, an overhead
light may have been connected to the wall switch and the old wires to the
outlet were just left behind.
>
> - Some electricians follow a pattern on supply into the top of the box and
next outlet out the bottom of the box (I may have that backwards) for wall
outlets, so if you are mapping multiple outlets, that may make things easier.
>
> Good luck with the project.  Taking the time to do the full circuit diagram
in my 1950 built house was critical to understanding the problems I was having
and figuring out a way to fix issues, such as every outlet but one in the
original portion of the house including the refrigerator on the same circuit.
I ended up rewiring all those outlets into four circuits and ended the common
computer lockups or beeping UPS warnings.

[email-masked]