12-3 wire keeps 45volts on leg that is turned off.

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Old 10-28-12, 06:08 AM
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12-3 wire keeps 45volts on leg that is turned off.

I had a 12-3 romex run from the breaker to a kitchen outlet. When one breaker was turned off that leg still showed about 35 to 45 volts. If I turn that breaker back on and the other breaker off the situation reverses. I have tested at the breaker at the pannel and when turned off I show 0 volts with each breaker, but when I test the wire I show voltage on the wire that is connected to the off breaker. Out of frustration, I ran a new romex to the box, installed a new breaker, but still have the problem. One breaker is a single 20amp breaker and the other is a tandem 20 amp breaker. I've heard that both breakers must be off when working on the 12-3 set-up, but I'm assuming that's when the working ends are wired. In my case I'm testing them at the end of the wire while they are not connected to anything.
Can anyone enlighten me? I'm three days into trying to figure this out and for a non-electricial, I'm ready to call for professional help.
 
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Old 10-28-12, 06:44 AM
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I think you're seeing induced voltage from the live leg. A sensitive meter will pick that up. Try testing with a test light.
 
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Old 10-28-12, 06:51 AM
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If you are using a digital multimeter you are seeing voltage induced from a parallel wire. A cheap analog multimeter would probably show zero as would a better quality digital meter.

One breaker is a single 20amp breaker and the other is a tandem 20 amp breaker.
It is wrong and dangerous to do that. You can only use a 240 volt two pole breakers, which a tandem isn't, or two 120 volt breakers handle tied which is probably impossible with your set up. Most importantly each breaker must be on opposite legs of your 240v. If you don't have 240 volts between black and red and handled tied it is wrong. If both breakers are on the same leg of the 240 the neutral can be overloaded, in extreme cases a fire could start without tripping a breaker.
 
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Old 10-28-12, 09:27 AM
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To stop seeing the phantom voltage reading, use a meter that won't pick it up - as others have said. That "voltage" isn't really there anyway.

To help us understand what you have now, and enable us to more accurately advise you, more information will be helpful: What is this cable going to be used for? To add to what Ray said, it needs to be protected by a two-pole breaker if it's feeding a single-phase load. It need to be protected by two 120V breakers joined with a handle tie if it's going to be used to feed two 120V circuits that will share the neutral. In either case, the two hot wires must be supplied from the two different hot legs in the panel. You should disconnect the wires from the breakers until you can correct that.

You also said
I had a 12-3 romex run from the breaker to a kitchen outlet.
Since it is in your kitchen, that raises the question of whether GFCI protection is needed.
 
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