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Wiring problem has me completely stumped.

Senna's picture

I am rewiring a bathroom. Thought it was a pretty simple job but I have run into a conundrum.

Coming into the bathroom I have one wire from the fuse box( A)  and what I thought was two branch circuits going out ( C and E). I have one connected one branch circuit (E) and it is working fine but when I add the other (C)  it trips the breaker.

The circuit in question (C) appears to me to be a branch circuit. It has three wires one red (which I have confirmed only goes to a light) and the usual black and one white wires.

However the black wire of the branch circuit in question and the white of the other circuit test positive for continuity when the power is off.  I can’t figure out why.

In the pictures wire 2 and 5 are the one that make contact.

Help greatly appreciated.

Have you opened the light (post #207042, reply #1 of 11)

Have you opened the light fixture to see how it's connected at that end?

When you say "positive for continuity", what kind of tester are you using?


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Yes I opened it up and it was (post #207042, reply #2 of 11)

Yes I opened it up and it was wired as I expected. Red wire to the light and the other wires passing through to other outlets.

Why don't you open up the (post #207042, reply #9 of 11)

Why don't you open up the light fixture again and disconnect the black wire there, then see if it's showing as connected to something at the switch.

(Keep in mind that a nail may have been put through the wire at some point.)


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

That top picture appears to (post #207042, reply #3 of 11)

That top picture appears to be feeding a 3 way switch loop. Is that a possibility?

 

What did you remove?

Greg

Orginally there were two (post #207042, reply #4 of 11)

Orginally there were two switches side be side one for the wahroom and the other a hall light. My aim was to relocate the washroom light switch in the bathroom and keep the hall light switch as is. The hall light switch is not a 3 way switch. The red wire ends at the hall light box.

 

Let me try to simplify the (post #207042, reply #5 of 11)

Let me try to simplify the problem.

I have one wire coming from the panel.

I have one branch circuit that when connected to the wire from the panel works but not all the lights and outlets are powered.

I have another branch circuit that also has an additional red wire that was use to power a light.

What is odd is that this second circuit shows conductivity between it's black wire and the white wire coming from the panel. I don't see why this is, and it is causing a short.

Do you see voltage on any (post #207042, reply #6 of 11)

Do you see voltage on any other wire but the black one from "A"

Greg

When I disconnect all the (post #207042, reply #7 of 11)

When I disconnect all the wires and turn on the circuit breaker only A gives me any reading. 120 volts between the white and black wires from A.

When I perform this test on the other two circuits nothing.

But when I connect the black from A and the cicruit in question I get 120v. Perhaps the polarity is reversed?

Be aware you can get a back (post #207042, reply #8 of 11)

Be aware you can get a back circuit through any load so if you apply voltage to the black of a lamp holder you will see 120v on the white if it is not connected back to the panel.


Maybe the best thing is to make a long enough meter lead so you can verfy where every wire goes by checking continuity with both ends disconnected.

Greg

It's been several months and (post #207042, reply #10 of 11)

It's been several months and I have been waiting for divine inspiration but I still haven't figured this out!

 

To recap - I have a branch circuit that blows the breaker whenever power is applied to it. The hot wire coming in from the panel gives me a completed circuit indication whenever it is connected to either the black or white of the circuit in question. But I get no indication that there is a short in the circuit - it should be isolated from the panel!  

Again, disconnect everything (post #207042, reply #11 of 11)

Again, disconnect everything at both ends, then check for continuity between the black and white wires leaving the panel.  If there is continuity then there's probably a nail through the cable somewhere.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville