Two circuit breakers control same light

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  #1  
Old 09-25-16, 12:40 PM
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Two circuit breakers control same light

I'm in the process of replacing all of my outlets and switches across my home. All of the ID labels on my breaker panel are worn off so I'm having to individually locate them one at a time and relabel them.

When I went to ID the circuit powering my kitchen, I noticed that two breakers are controlling power to the same light. If I turn off one of the breakers, and keep the other breaker on, the light stays on. The light is on a one way switch. My lighting in the kitchen is a fluorescent light fixture. Both breakers control various outlets within my kitchen.

Any ideas why this could be?
 
  #2  
Old 09-25-16, 12:48 PM
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Welcome to the forums.

You're telling us that you have two circuit breakers controlling the kitchen receptacles and if either one is off..... the kitchen light still works...... if the are both off..... the light is dead.

If that's the case then the receptacles should be doing the same exact thing. If one breaker is on.... all receptacles are on.
 
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Old 09-25-16, 02:25 PM
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Yes, you are correct. All the receptacles are either on or off based on whether or not one of the two breakers is on or off.

Why would two circuit breakers be powering the exact same equipment?
 
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Old 09-25-16, 02:34 PM
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Why would two circuit breakers be powering the exact same equipment?
Because someone didn't wire the circuit correctly.

This will not be an easy problem to find.
The first thing I'd do as any electrician is to remove the panel cover and identify the color of the wiring to the two breakers.
Are the circuit breakers right next to each other....... one directly over the other ?
 
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Old 09-25-16, 02:46 PM
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The circuits are #3 and #20 so opposite sides of the panel. Both wire colors are identical.
 
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Old 09-25-16, 02:56 PM
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Circuit 3 and 20 are both on the B leg of the service. Since they are both black and not together in the panel.... a multi wire branch circuit was not used.

You're going to have to pull the devices out of the boxes (DON'T unwire them) to figure out the wiring. Pictures of the wiring would help. http://www.doityourself.com/forum/el...-pictures.html

Is there a location where there are two duplex receptacles together ?
How about the light switch and a receptacle together ?
 
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Old 09-25-16, 03:04 PM
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It could also be two light switches in the same box.
 
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Old 09-26-16, 07:00 AM
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One thing to look for is separate feeds (different branch circuits) for the two halves of a duplex receptacle. For the typical daisy chain from one receptacle to the next there would be four (two wire) cables entering the box, two feeds and two continuations.

For this configuration, if the tab between the receptacle screws is not broken off then either breaker will control the entirety of both circuits, which I think is what the OP described.

Furthermore, with this configuration the tab between the screws must be broken off for both hot and neutral sides and the #20 neutral may not be matched with the #3 hot or vice versa at any of the receptacles or at a light.

Tab breaking is not done when you have two duplex receptacles in the same (double wide; double gang) box and circuit 3 feeds one whole receptacle and circuit 20 feeds the other whole receptacle.
 
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Old 09-29-16, 04:44 PM
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The switch theory might be the ticket. I have 4 switches ganged up on one side of my kitchen...two of which I don't know what they go to. Then on the other side, I have another 2 switches. I've attached a pic of that gang box. 1 of the two switches wasn't connected to anything so I've removed it. Picture is attached.

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Does that help any?

I'll check the receptacles as I get around to replacing them.

Thanks!
 
 

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