Bad Electricity

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  #1  
Old 07-03-05, 01:05 PM
skootsi
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Bad Electricity

I just finished installing two breaker boxes with three breakers and three circuits. One circuit serves my computer room, one my workshop, and one an air conditioner. To my surprise, they all work.

But when I turn on my computer, it makes a buzzing sound. Running it off either of the other circuits via an extension eliminates the problem. The wiring to the computer room is unchanged. It previously came off the main breaker box via a hokey junction box, which the new box replaced.

Since all three circuits are wired in the same way and have the same power source, it must be some detail problem. Any ideas as to what I should look for?

Jim T.
 
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  #2  
Old 07-03-05, 01:15 PM
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Perhaps you have a grounding problem. Did you keep the grounding wires and neutral wires isolated in each of these panels? Did you discard the bonding screw or strap? Do the subpanels have separate grounding bars and neutral bars? Did you run four wires (hot, hot, neutral, grounding) from the main panel to these subpanels?
 
  #3  
Old 07-03-05, 01:30 PM
skootsi
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Originally Posted by John Nelson
Perhaps you have a grounding problem. Did you keep the grounding wires and neutral wires isolated in each of these panels? Did you discard the bonding screw or strap? Do the subpanels have separate grounding bars and neutral bars? Did you run four wires (hot, hot, neutral, grounding) from the main panel to these subpanels?
Yes, the grounding wires are isolated. I didn't discard anything. Each subpanel has a grounding bar, to which the incoming power and outgoing circuit ground wires were carefully attached. The neutral incoming wire is joined to the outgoing (circuit) neutral wire of the same circuit.

Ran three wires (hot, neutral, and ground) from the main breaker box, which is itself a subpanel, 120V only.

But a ground problem could be it. Since only the one circuit is affected, I'm wondering if I nicked the insulation on a wire where it comes out of the cable. Very tight quarters, hard to see. I'll check that out.

Jim T.
 
  #4  
Old 07-03-05, 01:45 PM
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The neutral incoming wire is joined to the outgoing (circuit) neutral wire of the same circuit
I don't understand this comment. Because you have three circuits off each subpanel, don't you have one incoming neutral and three outgoing neutrals. Shouldn't these be connected on a neutral bar (isolated from the panel)?
 
  #5  
Old 07-03-05, 02:14 PM
skootsi
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Originally Posted by John Nelson
I don't understand this comment. Because you have three circuits off each subpanel, don't you have one incoming neutral and three outgoing neutrals. Shouldn't these be connected on a neutral bar (isolated from the panel)?
Sorry for the confusion. I have three circuits total, one in one box, two in the other. Small, two breaker boxes. I did it that way because I bought the boxes years ago for another purpose. The incoming power is branched off in a junction box/outlet box and fed to each subpanel. I live in the country, where we tend to do things like laying power lines along the ground so we don't forget and rototill them up. The arrangement looked perfectly sound to me.

Anyway, you were right about the ground problem. A ground wire slipped back when I twisted the wire nut on, so it was loose. I fixed that and all is well, if sloppy. Thanks.

Jim T.
 
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