I had a call the other day from one of my customers, to check out one of his rental houses. He didn't tell me what was wrong, just said it needed checking out to see what it needed. Well I've had jury duty this week, and couldn't get to it right away, so I figured it could wait since he said in a day or so would be alright. Well, I got off jury duty early today, and decided to go and check it out. I made a phone call and was told that a man, a boy, and a dog, had got shocked by touching the gas meter. Well I knew I needed to check it out as quick as possible. When I got there, to my supprise, I found 120 volts on the gas meter(measuring from the ground wire that was right next to it.) I went under the house and found 120 volts on the furnace and gas line there. I immediately turned off the circuit that was causing the voltage. After checking a few things, I pulled the romex out of the connector, and found that the hot conductor was mashed in a little. After I pulled it out, the voltage went away. I looked on the hot wire, and could barely see a pin point of copper showing. This was an old house, with no grounding wire, and the plumbing had been redone to plastic and someone had cut the ground wire off and left it hanging. The gas pipe was not hooked up to the ground wire either. There was nothing there to cause a fault and trip the breaker. I'm just thankful that no one was hurt seriously. One retired woman was living in the house with her daughter who had to use a wheel chair, and also some children. It seemed that they were unaware of the danger they were in, especially the children who would be more apt to be outside and under the house. I got there before it rained which could have been a very bad situation. This makes the part of the code, where it says to "ground the pipes that might be able to be energized", mean a whole lot more to me. Sometimes we just don't know how close we are to danger, and sometimes don't have the chance to steer clear from it. Hope this helps someone. It may save a life somewhere.... Steve
It reminds me of an incident last year. My local plumber had been installing some pipework for a homeowner just around the corner. I got a call about 8 p.m. one night -- Could I come quickly and take a look? He had been crawling through the attic and had gotten shocked on some structural metalwork. (It was an old pre-fab place with metal girder tie bars across the walls and tubular metal roof supports.) No way was he going back in there until it had been checked.
I found a Romex-type cable mashed under a pile of boxes, the insulation cut through so that a hot wire had contacted the edge of one of the girders.
By the time I left the structural metalwork was securely bonded to ground.