The year was 1978. My wife, my daughter, and I were moving into a house that we had just purchased. We soon discovered that one of the power outlets in a wall of my daughter's bedroom was dead. There were other outlets in the room that did work, so for the time being, we just arranged the furniture in such a way that it was not needed. About a year later, my daughter wanted to rearrange her room and the dead outlet became an issue with which to contend.
This house had been built in the 1950s and did not have grounded outlets. That is, all the wiring utilized only two wires, not three as in modern homes. I removed the cover for the problematic outlet and soon determined that the cause of the problem did not lie in that outlet box. There was just no power in the wire driving that outlet. So the problem at hand seemed to have expanded to being a house wiring problem. I became worried that perhaps someone had driven a nail or had run a drill through a power cable in the wall at some point. That could lead to serious safety issues such as an electrical fire so it became especially important to resolve this.
Here is the way the outlets presented themselves.
Both of these walls were outside walls of the house. A quick check in the basement revealed that no wiring related to these outlets was visible there. There was power at outlets A and B but just not at outlet C.
I shut off the power to the circuit at the breaker box and removed the outlet covers and the outlets themselves, allowing me to extend the wires for further checks.
Temporarily turning the power back on permitted me to see where the power was fed to this circuit at outlet A. I then killed the power again and started checking for continuity with an ohmeter. As expected, I found that there was a good connection between outlets A and B but not with C.
In fact, counter to my expectation that one of the wires would have been cut by some event such as the nail or drill, neither of the two conductors appearing at outlet C had continuity with any other wire anywhere. I could visualize how a nail or drill could even have cut through both wires. My worries intensified.
Determined to locate the issue and being an electronics experimenter, I whipped up a small radio transmitter to generate a weak radio signal at a frequency that could be detected by a pocket transistor radio. The idea was that I could connect the transmitter to one of the wires and then follow the wire inside the wall by following the radio signal with the transistor radio. I tested and found that it worked well using the known good wire from outlet A to outlet B. Then I set out to follow the wire from outlet B that should lead to outlet C.
I was able to follow the signal just fine but not long after going around the corner of the room, the signal disappeared. I marked the spot on the wall where it ended with an X.
Then I repeated the procedure starting with the wire in outlet C. Again, I was able to follow the signal in the wall until it abruptly ended the same way and right at the very same point where my X was on the wall.
I wondered if I would see anything if I checked the outside of the house but that revealed nothing at all. There was no evidence that the wall had ever been disturbed from the exterior at that location. I pondered what to do next.
The walls were plastered with a sand finish. I didn't really want to cut into the wall but it seemed that I had no other choice except to disconnect both ends of the wire from outlet B to outlet C. I opted to cut into the wall at the point marked with my X. I started chipping away the plaster and dug into the wall. As soon as I had a small hole, I peered inside and saw the power wire coiled up inside the wall. I started removing more plaster and discovered the answer to the entire problem. There was an additional outlet box mounted in the wall. The two wires that I traced inside the wall were both coiled up inside that box.
It turns out that the person who had plastered the wall had plastered right over this outlet box, burying it in the wall. It had been hidden inside the wall ever since the house had been built more than twenty years earlier. Soon I had installed a new outlet in that box and re-installed the others and all was better than ever.
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