Just bought a home built in the 1920's, the knob-and-tube was updated a couple times at different eras but there is still fabric wrapped ungrounded wiring (FWUW) in many rooms. The living room (and crawlspace/storage beneath it) is all FWUW on one circuit, two outlets on the circuit work six outlets (and two lights) don't. They didn't stop working all of a sudden, it was a gradual decline which I hope can help lead to the solution:
- 2 weeks ago the 6 outlets and 2 lights just stopped working one night, the next day I tried the lights again and they came on for about 1 minute and then died again
- The next day I measured the voltage on several of the outlets and they read ~1v across hot-neutral
- The next day, investigating further, I measured them again and now they read ~60v across hot-neutral
- A couple days later I plugged in a light into one of the outlets (forgetting they were dead) and the light worked for about 5 minutes and then died.
- Now all dead outlets read ~1v.
- The two working outlets read ~125v and have continuity across hot-neutral, the dead outlets read ~1v and have no continuity across hot-neutral.
Its an old house with lathe and plaster so its difficult to trace wires but I can't find an obvious junction box to investigate for bad connections, there are no GFCIs on the circuit and none of the outlets I found have pigtails w/bad connections.
Is there a particular issue I should be looking for and what technique(s) can I use to track it down? Looking around here and elsewhere it could be a loose wire (haven't found one yet), a GFCI (none on the circuit) or a faulty 'shared neutral'?
Best Answer
Having no voltage indicated on your meter would indicate a bad connection on the hot wire for most meters (an open neutral would show some voltage with high impeadance meters that are normally used). I would start checking at the last working outlet then the first dead one. When the new outlets or wiring was installed did they use the back stabs on the outlets? Back stabs or push in connections are notorious for failing. Most of the knob and tube replacements I have done the boxes were in the attic, it is very rare for the boxes to be in the crawl space but I did find several on 1 job. Use caution in the attic because sometimes the in wall knob & tube was left in place but the feeder wires to that junction box was updated (still allowed by code). So start at the 2 outlets since they would be the easy ones to get to then start checking the attic junction boxes.