I recently had to replace a bad water heater in a small apartment that I have over a pole barn. While replacing it I noticed, even without the old water heater removed, that the ground wire and the water pipe going to the heater would shock me if I grabbed them.
This morning my son was using the water spicket on the outside of the barn and he said he was also shocked.
How can I diagnose and fix this problem? I'll be watching this thread closely so if anybody needs more information or needs me to test something just let me know.
You will need to find out what is energizing the pipes. You could try shutting off the breakers in the apartment's electrical panel. Use a voltmeter to measure from the pipes to some other known electrical ground. You want to see which circuit has some defect or has some appliance leaking current to ground or otherwise having some live part touching its chassis or frame or a pipe, as you turn the circuits on one at a time.
A correctly wired subpanel fed from the main house also has a ground wire accompanying the hot wires and neutrals back to the main house panel. In addition, a grounding electrode is needed. This could be the water pipe exiting the building if that is metal and buried, otherwise you need a ground rod.
Grounds and neutrals must be kept separate except at the panel where the main disconnecting switch or breaker is located; no other disconnecting switch from the point upstream to the electric meter.
Thanks for the tips. I'm not sure this matters but I need to clarify a few things.
1. The barn (and water well for that matter) are both on a separate meter from the house. There is no electrical connection between the house and the barn/apartment.
2. The power coming into the barn comes in at a meter on an outside wall of the barn. Directly opposite that on the inside of the barn is a single breaker switch and about a foot from that is a standard breaker box with a main shutoff and the various breakers coming off the bus.
OK, using AllanJ's suggestion, I've made progress.
I isolated the 'leak' to a single light switch. Somehow either the switch or the shop lights connected to it are causing the problem. I have a question though. The pipes and the lights do come into contact anywhere. Is that switch or those lights leaking power into the ground which is then going back to the panel and going through all of the other circuits which somewhere along the way come into contact with or use the metal pipes for a ground? :huh:
The plumbing system and the electrical grounding system are supposed to be electrically connected (bonded). In your case (not a subpanel connected to the main house) the ground system includes the combination neutral/ground going from the panel with the main disconnect switch over to the meter and up to the utility pole.
It is possible for a defective light or appliancem, or wires improperly touching in an outlet (incl. switch) box to energize the ground wire or conduit in a branch circuit and this in turn comes back to the panel and energizes the entire electrical ground system. This is called a ground fault. The grounding up to the utility pole and the grounding down to the ground rod or cold water pipe exiting underground is supposed to keep it safe if not to the point where you can't feel a shock (or trip an applicable breaker) but still you should get it fixed as soon as possible.
Fluorescent shop lights often have sharp edges inside that could cut and make contact with live wires and also the ballast in a cheap shop light could have a ground fault.
If the switch directly behind the meter is a master switch that controls the breaker panel then grounds and neutrals in the panel must be kept separate, with separate ground and neutral wires runing between the breaker panel and this switch.
Good stuff, AllanJ. You da man! Thanks for your help.
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