Knob + tube extention

[readydave8]

hard to sell arc faults

hard to sell arc faults

Had a call this week from a lady asking why her receptacle cover was illuminated. Had her turn off breaker. When I got there the receptacle was scorched, got hot enough to melt and char part of the blue plastic box.

I fixed the problem and explained as well as I could that arc fault breakers would trip if this happened elsewhere, she had 30 single pole so I mentioned $1200 for breakers. She didn't want them.

This is probably a $450,000 house in a gated golf course community.

 

[dlhoule]

Problem with Knob & Tube

Problem with Knob & Tube

Any suggestions on how to locate an open neutral in a knob & tube installation. I'm thinking I may have to go right to the panel with a white wire to pick up the neutral. That won't be easy either because the panel is on an inside wall of kitchen. I could pick up neutral from nearby circuit but it isn't on the same circuit.

 

[acrwc10]

Any suggestions on how to locate an open neutral in a knob & tube installation. I'm thinking I may have to go right to the panel with a white wire to pick up the neutral. That won't be easy either because the panel is on an inside wall of kitchen. I could pick up neutral from nearby circuit but it isn't on the same circuit.

I would suggest looking for J boxes in the attic or under floor first. If that doesn't do it you need a circuit tracer that you can follow the wire in the wall till it stops. I would not suggest running a separate "new" neutral because if you don't run with the original circuit conductors you will create EMF and possibly other issues in the house. It is always best to find the source of the problem or abandon the old circuit completely and run all new conductors.

 

[acrwc10]

I should add, I have seen one house that had only 2 wire circuits and had fused hots and fused neutrals. This was a very old house.

 

[al hildenbrand]

Any suggestions . . .

I agree with turning to an electronic tracer. I've had good results with an open tracer in the past, injecting the signal on the floating part of the neutral and tracing back till the signal disappears. The plaster & wood lath is a benign environment for signal scattering.

 

[dlhoule]

Which Circuit Tracer?

Which Circuit Tracer?

Which circuit tracer would you recommend? I've tried a couple of them without any success. The owner is already unhappy with the holes in I've put in ceiling and floor. The duplex outlet without the neutral has romex to it and I did get the romex traced back to a k&T connection, but the neutral of the k&t is open.

 

[acrwc10]

Which circuit tracer would you recommend? I've tried a couple of them without any success. The owner is already unhappy with the holes in I've put in ceiling and floor. The duplex outlet without the neutral has romex to it and I did get the romex traced back to a k&T connection, but the neutral of the k&t is open.

You could put a load on each circuit one at a time then put an amp probe on the neutrals, the neutral that doesn't show a load is your broken neutral.
If you get a tracer, you can check it back from the outlet going toward the panel.
Greenlee makes a good one.

 

[dlhoule]

Each circuit does have a load on it. I have 1 duplex outlet without the neutral, which is fed from a k&t in ceiling of kitchen. I just don't know where the next connection for that neutral is coming from. Everything else is working properly.

 

[al hildenbrand]

Which circuit tracer would you recommend?

Well, mine's an old Greenlee 2008 Open Circuit Tracer.

The trick, IMO, lies in treating the neutral that is floating as an antenna. A good antenna works when it's not touching anything conductive. In the case of the neutral, the tracer signal will travel off on spurious paths through plugged in utilization equipment, bulbs, etc, that are still connected. So part of the work is disconnecting those spurious paths as one discovers them while tracing the neutral back towards the panel.