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Dishwasher trips breaker immediately--need troubleshooting help

Dishwasher trips breaker immediately--need troubleshooting help

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  #1  
Old 09-02-14, 06:10 PM
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Dishwasher trips breaker immediately--need troubleshooting help

After some kitchen renovations the dishwasher was reinstalled and it trips the breaker instantly. All connections seem good. The house wiring is interesting to say the least. There is a junction box on the wall behind the dishwasher. The wire coming into the junction box has two hot wires. One powers the dishwasher on its own circuit, and the other powers some of the kitchen outlets on a different circuit. They share the ground. There was also a switch on the dishwasher line that we removed but I can't believe that would have anything to do with the issue. We disconnected the dishwasher circuit and attached the dishwasher solely to the outlet circuit and it tripped that breaker immediately as well. To me there is a problem with the dishwasher itself. I guess it's just coincidental that it happened to work fine when we removed it and now it doesn't. If anyone has any tips on how to troubleshoot this dead short I would appreciate it. Thanks in advance.
 
  #2  
Old 09-02-14, 06:55 PM
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How many and what color wires in the dishwasher circuit box. Was the switch where power came in or was it a switch loop with power at the DW.
The wire coming into the junction box has two hot wires. One powers the dishwasher on its own circuit, and the other powers some of the kitchen outlets on a different circuit.
No, not two wires**, two cables*. A very different thing.
There was also a switch on the dishwasher line that we removed but I can't believe that would have anything to do with the issue.
I suspect that is where the problem is. Explain the wiring and what you did.

*Cable: Two or more conductors in a metallic or non metallic sheath.
**Wire: A single conductor.
 
  #3  
Old 09-03-14, 05:45 PM
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It was two hot wires in one cable (red, black, white, and copper). Of course the red and black were hot. The red is the dishwasher circuit. The black is for two GFCI outlets (separate circuit). The white wires were twisted together. We found that when we undid the white wires and connected the single white and the red to the dishwasher, it worked fine. SO we concluded that there is an issue with the cable that goes from that junction box to the two outlets. Clearly something with the white wire. Possibly a mouse chewed it somewhere in the wall. Could a bad GFCI cause this problem?
 
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Old 09-03-14, 05:49 PM
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If you have 240 volts between black and red you have a multiwire circuit. Are you familiar with multiwire circuits?
 
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Old 09-03-14, 06:12 PM
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You connect white and red to dishwasher and that circuit was ok.
Now disconnect the white and red from the dishwasher and connect the black and white to the receptacles. Do the receptacles work ok ?

They share the ground.
Yes... they share the same BARE ground and they also share the white wire which is neutral... not ground.
 
  #6  
Old 09-04-14, 06:18 PM
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We solved it. Turned out to be a bad GFCI. We replaced it and all is good. Thanks to everyone for the help.
 
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Old 09-04-14, 06:34 PM
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Glad you got it but your post said a breaker was tripping. Was it a GFCI breaker?
 
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Old 09-04-14, 09:23 PM
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It would appear that it was a GFCI that was tripping and it may have been caused by introducing ground on the neutral wire.
 
  #9  
Old 09-05-14, 05:22 AM
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Why would you have a dishwasher on a gfci?
 
  #10  
Old 09-07-14, 06:38 AM
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Originally Posted by dirtydickey View Post
Why would you have a dishwasher on a gfci?
That's what I'm wondering.. and what I assume you have is a 3 wire home run to a 4 in. Sq box.. With that home run your feeding one of your two kitchen gfci circuits and your dishwasher off of the other hot leg.. do you know if the nm feeding that junction is 12 or 14 awg? It should say on the side of the sheath (assuming this cable predates color code)

Troubleshooting. Always start from the end and work your way to the panel..

Disconnect the nm at the dishwasher cap it off and see if your breaker trips.. If so, disconnect the feed from the junction box and see if it trips if not then the problem is in your outlet circuit. However if it still trips with nothing being fed by that home run, then the problem is in the home run itself.. Hope that makes sense
 
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Old 09-07-14, 09:36 AM
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I don't remember any mention of the dishwasher being on a GFI circuit although we never did get the full story.
 
 

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