4 ms·

Have you actually checked the ground for continuity? IN my house, I found that many of the upstairs outlets (wired with BX) had their grounds bonded to the wate

Have you actually checked the ground for continuity? IN my house, I found that many of the upstairs outlets (wired with BX) had their grounds bonded to the water pipes in my house, instead of run directly to the box, and then the water pipe was bonded to the box down near the service entrance. Unfortunately, there was no ground continuity because at some point a pipe segment had been replaced with PVC instead of copper and the continuity ended. Bonding grounds to pipes was very common in older houses and is a common source of bad ground loops and electrical noise.

sandworm101 8y ago
>> a pipe segment had been replaced with PVC instead of copper Which is why when you do that you are supposed to always install a wire to jump over the now non-conductive section of pipe.
- abakker 8y ago
  Exactly what I did. I’m not sure the original homeowner knew that it mattered. I first noticed the issue with a stepper motor project I was working on. It was very interesting to hear the reduction in audible noise from the motors when the grounding was fixed.
- atesti 8y ago
  Also if current runs over pipes, there might be more corrosion when different kinds of metal meet. You should never run ground over pipes, but instead use a dedicated copper wire
fastaguy88 8y ago
This is a true story. One night, I went down into my basement and heard a snapping sound, and looked to see sparking between a 12-14G copper ground wire (from somewhere) and my water supply pipe. It turns out that my 1952-build house did NOT have a ground/earth for the panel, and a squirrel had chewed all but the last few strands of the neutral coming from the power pole. Most of the return from the house was going through this piddly ground strap, and it was not happy. I called the power company, and they were kind enough to install an new neutral almost immediately (perhaps at night). I then called an electrician, who grounded my panel. I am still amazed that my refrigerators and ovens worked, and wonder what would have happened if I had not heard the snapping sound.
howard941 8y ago
> Have you actually checked the ground for continuity? No, not in a reliable way. I have continuity between neutral and ground at the socket but I can't tell if what I'm seeing is some bozo's swamp "bonding" behind one of the branch outlets or the actual bonding near the service entrance.

sandworm101 8y ago

>> a pipe segment had been replaced with PVC instead of copper Which is why when you do that you are supposed to always install a wire to jump over the now non-conductive section of pipe.

abakker 8y ago
Exactly what I did. I’m not sure the original homeowner knew that it mattered. I first noticed the issue with a stepper motor project I was working on. It was very interesting to hear the reduction in audible noise from the motors when the grounding was fixed.
atesti 8y ago
Also if current runs over pipes, there might be more corrosion when different kinds of metal meet. You should never run ground over pipes, but instead use a dedicated copper wire

fastaguy88 8y ago

This is a true story. One night, I went down into my basement and heard a snapping sound, and looked to see sparking between a 12-14G copper ground wire (from somewhere) and my water supply pipe. It turns out that my 1952-build house did NOT have a ground/earth for the panel, and a squirrel had chewed all but the last few strands of the neutral coming from the power pole. Most of the return from the house was going through this piddly ground strap, and it was not happy. I called the power company, and they were kind enough to install an new neutral almost immediately (perhaps at night). I then called an electrician, who grounded my panel. I am still amazed that my refrigerators and ovens worked, and wonder what would have happened if I had not heard the snapping sound.

howard941 8y ago

> Have you actually checked the ground for continuity? No, not in a reliable way. I have continuity between neutral and ground at the socket but I can't tell if what I'm seeing is some bozo's swamp "bonding" behind one of the branch outlets or the actual bonding near the service entrance.