Getting Shocked

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  #1  
Old 06-01-05, 03:30 AM
radio727
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Getting Shocked

I recently purchased a home and it has a metal shed out back with a light and outlet inside it. The problem is, when I touch the metal on the shed, I get a shock. Not just a little one but you can really feel it. I shut the power off and looked at the wiring. The outlet and light are ok, I mean the white goes to neutral and black to hot and ground to the metal handy box (which is screwed to one of the metal studs in the shed. On the breaker side, it's a squard d breaker 15 amp. This breaker has a red wire on it and the one next to it has the black. Looks like they got 2 circuits out of one 10/3 wire. I noticed that the neutral go to the neutral bar but there is no ground wire coming out of the 10/3 uf romex, just a black, red, and white. In the shed I measure 117 volts from neutral to hot and I'm getting 80 volts from neutral to ground. I temporarily disconnected the ground wire in the outlet box to eliminate the shocks. Do I need to put in a ground rod for the shed or should I run a new wire to it all together. Also, where do you think the 80 volts are coming from?
Thanks for you help.
Joe
 
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  #2  
Old 06-01-05, 04:29 AM
WFO
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Sounds like the guy is using the neutral for an earth ground. Since the neutral is the return path for any 120 volt load, by tying it to the building he made the shed part of the circuit. When you touched it, you became part of the circuit.
Definitely not safe!
 
  #3  
Old 06-01-05, 04:43 AM
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You have several problems here. Using 10-3 would imply a multi wire circuit. There is nothing wrong with a multi wire circuit, if done properly, but this is not.

Any service to a shed requires GFCI protection. At the very least the receptacle in the shed needs to be a GFCI receptacle. However, the breaker in the main panel would need to be a GFCI if the wire is not buried deep enough. That is problem number one.

Problem number two is that a ground wire is needed. It is dangerous to not have a proper ground wire when dealing with a metal shed.

I suggest that you immediately turn off this breaker and do not turn it on again until you have replaced the wire going to the shed. You need to abandon the 10-3 wire that is in place, and put in new wire.

You didn't tell us the distance from the panel to the shed, so it's hard to say what size wire is needed. Depending on what you plan to do in the shed I would run either a single 20 amp circuit, or a 20 amp multi wire circuit. Unless you want to bury the wire deep enough, I would use a GFCI breaker.

The 80 volts you are reading is phantom voltage. Ignore it. It is because the ground is open.
 
  #4  
Old 06-01-05, 05:14 AM
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Normally I would agree that the 80V reading is a 'phantom', found just about whenever you make a measurement on an open circuit.

However in this case, the 80V measurement, combined with the fact that you are actually getting shocked, suggests that this may be a real voltage measurement. In particular, you may have a significant current flowing through the ground, creating exposed shock hazards and step potentials.

You've left out a good bit of the story here; so I have a few questions:

1) What were you touching and what were you standing on when you got shocked? Was the shock just from the shed itself when you were standing on the ground, or was it from the light switch?

2) What sort of wire feeds into the shed? You mention in the shed a black/white/ground, but at the breaker you mention a 10/3 black/red/white with no ground. _Somewhere_ there was a transition; where? Is the breaker that you describe in the shed or at your main panel. If at your main panel, then follow the wire; does the 10/3 split at some point to send 10/2 UF to the shed? Is it possible that what you call the 'ground' is actually the red wire stripped bare at the shed? If the supply to the shed has a ground wire, and the ground wire is not connected at your main panel, then where is the ground wire actually connected?

3) Can you describe the circuit feeding the shed, from your main panel out to the last receptacle, in order of which sort of wire is used, where the junctions are, and what sort of switches or outlet devices are used?

4) Ground rods will _not_ fix this problem. You need to find the source of the current that is leaking that caused your shock.

-Jon
 
  #5  
Old 06-05-05, 08:03 PM
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Join Date: May 2005
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Here is what I am seeing in all of this.

You are saying that in the outlet you disconnected the ground and that eliminated the shocks. Also you have a red wire in the box unacounted for in the shed, and a ground wire in the shed unacounted for in the box.

You need to acount for these wires. Normally I would say that it sounds like one of the hot wires (red or black) have broken insulation somewhere and are in contact with the ground. I'm going to guess red since the black is abcounted for and working. But in this case I would look into the possibility that somewhere along the line some bonehead managed to connect the red wire from the box to the ground wire in the shed.
 
  #6  
Old 06-07-05, 03:12 PM
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Thought of something else - are you sure this is the exact same peice of wire out of the box as the one in the shed? In other words is it possible there are two peices of wire spliced along the way from the box to the shed?

This seems a little out there, but it is definatly possible - you definatly have a 3 conductor wire in the box - you have a red, black, and white. Do you have maybe a 2 conductor wire in the shed? What I am thinking is that someone way back whenever the shed was put in might have decided to use the 3 conductor wire curcuit for the power for the shed. If they only had 2 conductor wire (or that is what was bought) that could explain it if the person knew just enough about electric that they needed two hot wires and a neutral, but said to hell with the ground, we need that third (bare) wire for a hot.
 
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