Posted: 7/10/2009 7:02:19 PM EDT
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While cleaning up some in the garage today, I was leaning on a metal switch box that controls some shop lights I put in about 10 years ago. I leaned down to pick up some stuff next to a drill press on the concrete floor and brushed against the vise handle. I thought a mosquito got me and pulled my hand back, but saw nothing. I knew I touched the metal handle and touched it again with the back of my hand and got a little zap. I did this a couple of times to be sure I was not imagining it. Same thing with it plugged in or not.
I touched the switch box and the next junction box in line and felt the same thing. Tired of being a living meter, I broke out a multi meter and found that there was a fluxuating 8-20- volts between the two boxes. When I turn the switch off, there is no voltage between the boxes. What should I be looking for besides wires touching metal in the boxes? Grounds? What? Thanks for the help in advance. |
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That was my thought. I started looking, working my way backwards from the end of the line and got bored so I quit for the day. I was hoping it was in one of the shop lights or switches but no good so far. I got into a junction box and found it was before that point so I'll keep tracing I guess.
Anyone know an easy way to find this little bastard? |
| If it is a metal box make sure that the ground wire is tied to the switch box and the receptacle box. If the switch and receptacle have the strap ground and are screwed tight this should ground the boxes. This will help stop the shocking and might show the problem . Any fence chargers or bug zappers on the circuit? |
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Grounds look to be in place in the boxes and fixtures I have looked in so far.
No zappers or fence chargers. The only zapper right now is my drill press because it's on concrete and well grounded, but not plugged in. BzzzzzzZZZZzzzzzzt ! With a meter on it it's averaging about 6 volts. |
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Quoted:
Grounds look to be in place in the boxes and fixtures I have looked in so far. No zappers or fence chargers. The only zapper right now is my drill press because it's on concrete and well grounded, but not plugged in. BzzzzzzZZZZzzzzzzt ! With a meter on it it's averaging about 6 volts. There are a number of tricks you can use to find out the source impedance that is sullying the voltage. This often helps figure out what the source could be. A couple of 1 kohm resistors from the 'live' circuit to ground and measure the voltage drop across the resistors. The current is then V/R. It it is very small think bad insulation. If it is larger than a few milliamps think hot wire touching something ungrounded, and then energizing everything hooked to the (bad) ground. |