Losing voltage in an outlet

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  #1  
Old 08-10-11, 07:49 PM
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Losing voltage in an outlet

I wired an outlet under my kitchen sink, for a disposal. I have a non-contact voltage detector and while holding it to the hot wire on the outlet it says I have voltage to the outlet when the switch is on, as it should be. However, as soon as I plug the disposal into the outlet I lose the voltage. The disposal works when I trouble shoot it with an extension cord.
What am I doing wrong?
Scott
 

Last edited by pcboss; 08-12-11 at 10:02 AM. Reason: changed current to voltage
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  #2  
Old 08-10-11, 08:53 PM
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I have a current meter
They are useless many times because they can pick up induced voltages with little actual power. You need a cheap analog multimeter, good quality digital multimeter, or a test light to do any real troubleshooting.

First though tell us step by step how you wired it. Where did you get power, how did you wire the switch? Does the power go to the switch first?
 
  #3  
Old 08-11-11, 04:29 PM
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First off I should say I guess it's not a meter I'm using, but a non-contact voltage tester.

I'm running 12-3 (black, red, white, ground) to a 2 switch box. Black to under cabinet lighting switch, red to a garbage disposal switch. Whites are all spliced together. The lighting works, so I'll skip that. The red wire goes to the bottom of the garbage disposal switch. 12-2 comes up from a regular outlet under the sink. (I had a GFCI, but switched it out, thinking that was the problem.) The black wire from the 12-2 from under the sink connects to the top of the disposal switch. The white is spliced in with the others.

My meter shows voltage in from the red wire. It shows voltage on the black wire, down to the outlet under the sink, when the switch is turned on, and no voltage when switched off. Everything is good so far. When I get under the sink, with the garbage disposal switch turned on, but nothing plugged in, I show voltage. As soon as I plug the disposal in, I lose voltage on the black wire. This occurs when any devise is plugged into the outlet.

End result... I can't use my garbage disposal.

I ran an extension cord from another outlet to the disposal and it works just fine. I'm flummoxed. It seems as if I've done everything properly.

Thanks for any help offered.
Scott
 

Last edited by pcboss; 08-12-11 at 10:05 AM. Reason: correction for clarity
  #4  
Old 08-11-11, 05:30 PM
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I'm running 12-3 (black, red, white, ground) to a 2 switch box. Black to under cabinet lighting switch, red to a garbage disposal switch. .... The red wire goes to the bottom of the garbage disposal switch. 12-2 comes up from a regular outlet under the sink.
Is this a multi-wire circuit connected to a 240 volt breaker? If not why a 3-wire cable?
 
  #5  
Old 08-11-11, 06:59 PM
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Ray,
Not sure how to answer that. It's what's in the wall. My understanding is that it's a 3 wire cable to separate the lights from disposal, so as not to overload the circuit. If that's not an issue, I suppose I could piggy back the disposal off the lights.
Doesn't explain why the lose of current is happening, though.
scott
 
  #6  
Old 08-11-11, 07:44 PM
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Your description indicates a possible multi-wire circuit. You really need a test light or meter to do some tests. First though at the breaker box the red and black should be connected to a two pole breaker but it may be connected to two single pole breakers. One of those breakers may be tripped. You need to turn the 240v breaker or 120v breakers all the way off then on and test if you now have power.
 
  #7  
Old 08-12-11, 10:07 AM
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Have you checked the connections at the receptacle? Be sure to check the neutral wirenut connection also.
 
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