low voltage on lightswitch plate. How can I fix this problem?

When I run my finger across my metal cover plate on one of my light switches in my basement I feel a strange vibration sensation. I have three good books on home wiring and know how to install light fixtures, outlets and switches. I also know about grounding. I am going to build a home theater room in my basement and would like to solve this problem before I wire the new room.

Please let me know what this problem may be.

Thanks, Dan

Reply to
Dan J.
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Test the cover plate to see whether it's live.

Sylvia.

Reply to
Sylvia Else

Dan. Is there any dampness in the walls of the basement?? Regards. Len.

Reply to
GKN

I did come across one problem in a cellar many years ago with similar symptoms - except the problem was intermittent. The switch and pattress were perfect and perfectly grounded and I could find nothing wrong. The walls were dry and perfect too.

To cut a very, very long story short. The problem was the domestic water pump which was improperly earthed and faulty. It was connected using plastic pipes and was sitting on the concrete floor that was isolated from "ground" by a good dpc and membrane. The pump was in an enclosure a considerable distance from the switch and nearer other switches. The floor had a crack in it that meandered from the pump enclosure to the floor below the one switch in the room that caused problems - all the others around the room were fine.

Standing at that one spot in the room and touching the switch completed the circuit from live, through the faulty pump to the damp spot underneath it, along the damp crack (made damp by water leaking from the pump) to the floor under the switch, through the floor covering, through the person to the metal body of the switch and hence to the return, bonded to "earth". The leakage current wasn't enough to trip the 30 mA RCD but was enough to be felt.

The intermittent bit was, when they were away for a few days or otherwise not using much water, the crack dried out. After a few days of being back, the crack started conducting enough to matter.

Oh, how I laughed when I finally worked it out.

Reply to
Palindr☻me

Interesting story. The moral is that we tend to think that GND must be cold, at zero potential, but it could be that the *local* GND is hot and the chassis/faceplate is actually well earthed. Earthed here is intended as being closer to the potential of the local Green and White wires.

MG

Reply to
MG

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