Electrical problem

[pisces]

Opened up the cabin for the summer and had no A/C current at the electric hot water heater outlet.Replaced the circuit breaker, still no current. Pulled the outlet from the workbox and put the multimeter across the terminals and still no voltage. I have to assume there is a loss of continuity somewhere between point A (circuit box) and point B (end outlet). Wire is white Romex, dont know how old, but my guess is that this work was done in 1970s.

Can Romex go bad? Could mice have chewed through it? The circuit breaker does not trip, just no current at user end. Of course, the wiring runs through walls and under subfloors, so replacing it will be a B****. Any advise?

[delcecchi]

Mice don't chew through copper wire, to the best of my knowledge.

If you are lucky it is bad connection in breaker box. If you are unlucky, there is a splice or other connection somewhere between the box and the outlet that went bad. Now you know why the code doesn't allow connections except in an accessible box.

I worry about that with our cabin too.

[PurpleFloyd]

I disagree.

Quote:

Rats, squirrels and mice can – and will – chew your electrical wiring. This causes a major fire hazard. What’s worse? The most common place for this to happen is in the attic, above your smoke detectors. As if this weren’t hassle enough, there’s the expense of replacing and/or repairing damaged wires.

Here are some photos taken by our Technician, Matthew, during a recent inspection.

Quote:

Why do rodents chew wires?

To control the length of their teeth and sharpen them. The front incisors of rodents never stop growing!

How common are rodent-related fires?

It is estimated that rats and other rodents cause 25,000 fires annually. It has also been estimated that up to 20% of undetermined fires are caused by rodents each year.

[CAMAN]

PF I believe Del was saying they don't chew through the copper, causing it to actually break and lose continuity. I too have seen many wires chewed, but have never seen any where they actually started into the copper.

Best way to figure out what is going on is to get a wire tracer system (Fox and Hound) and see if you can trace where the break could be.

[kerryd15]

have you checked the post on the breaker for voltage? how many breakers you have or what style box? Is this 110 or 220? You could have lost one side of the breaker box. There are generally 2 hot wires and a ground. Every other breaker pulls from a separate side. Are you sure you changed the right breaker?

[Darrell Larson]

Have you checked to see if you have power on the load side of (at) the breaker?

[delcecchi]

PF I believe Del was saying they don't chew through the copper, causing it to actually break and lose continuity. I too have seen many wires chewed, but have never seen any where they actually started into the copper.

Best way to figure out what is going on is to get a wire tracer system (Fox and Hound) and see if you can trace where the break could be.

Yes, that is what I meant. If there is no juice but the fuse/breaker doesn't blow then it isn't a short or it would trip the breaker, and I didn't think a critter would bite through the wire, at least not one that thick.

Seemed to me that a problem in the box is more likely.

[pisces]

Okay, I'll try to answer as best as my limited electrical knowledge can. I assume it is 220V coming into the cabin panel, where it is broken into several 110 amp circuits. It is a 10 amp, 110V breaker that is in question. It is a dedicated circuit (nothing else uses this breaker) supplying AC to the outlet in the utility room which is where I plug in the hot water heater and nothing else. I assume it is a "homerun" from point A to point B, but I guess there could be a junction box somewhere along the way, but I don't know.I definitely know that this is the correct breaker, as I have turned it on and off every weekend for several years.

It is a grounded circuit with a ground wire coming all the way back to the panel. There are two hot wires: the white one is attached to a common buss in the upper part on the panel into a hole with a set screw. The black wire is plugged into the breaker by placing it beneath a small plate and then squished there by tightening a copper screw.

The panel has a Main on/off and 8 breakers, 4 on the right, 4 on the left. All are working but this one, which is the bottom one on right side. I did try placing this breaker one spot lower on the "rib" thinking maybe it was sitting on a dead spot, but that made no difference. I then took the black wire out from this breaker and put it into the kitchen lights breaker which I knew was working and tested at the outlet, but still no voltage there. Does this experiment make sense as I thought it would?

My next thought is as follows: the panel is mounted on an exterior wall about 18 inches below the ceiling. By removing one small piece of wood panel, I can access the Romex as it runs up from the panel before disappearing into the ceiling. I can identify which wire is in question, and I could test that wire above the panel and then I would know the problem was downstream of the panel. I could strip away a bit of the insulation and apply my voltmeter there, or is there a better way to do this?

Any thoughts or suggestions now? Thanks to all who answered.

[delcecchi]

Yes, 220 comes in to the panel. The 220 is +/- 110 with respect to ground/neutral (they are connected together somewhere near or in the panel)

In a 110 volt circuit, the black wire is hot and the white wire is neutral or return.

By putting a known 110 volts on the black wire and still not seeing anything at the outlet, it seems to me that it can be concluded that there is a bad connection somewhere.

I think the next thing to do is check the voltage at the wires on the back of the plug, if you haven't already done so.

If you have 110 volts at the black wire in the panel and no volts on the black wire in the outlet box, that's a bad sign. On the other hand, outlets can go bad, or the wire can come loose or corrode where it connects to the outlet.

Any junctions or splices are supposed to be accessible but you never know for sure. I find it hard to believe that something could go wrong in the middle of a piece of romex unless you have been nailing or drilling or something like that.

[CAMAN]

Quote:

I could strip away a bit of the insulation and apply my voltmeter there, or is there a better way to do this? 

DO NOT DO THIS! That is a fire ready to happen.

Since it sounds like you have already opened up the panel to replace the breaker you are probably somewhat comfortable going in there again. I would turn off the main breaker, pull the panel cover, find the breaker in question and the neutral bus bar. Carefully turn the main back on and with your volt meter measure the voltage between the neutral bar and the wire coming off the breaker. It should be 120 volts. If not 120, your breaker or panel have a problem, if it is 120 you have a break somewhere between the panel and outlet.