Two breakers required to de-energize circuit

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jeff48356

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Livonia, Michigan
I've seen this a few times at people's houses over the years, where the homeowner tried to replace a device, but was unable to de-energize the circuit unless he turns off two breakers. Turning either one of them back on will re-energize the circuit. I know this is a serious problem, but how would you approach it for troubleshooting? What techniques would you use?
 
LarryFine said:
Remove and cap one of the two breakers' wires.
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That would be at least a few code violations.

You still have two neutrals carrying load, some not in the same NM jacket.

A home wired at 3va per foot needs all the original circuits to remain complaint, if the SABCs, same thing.
 
My brother-in-law had that situation in his house. EMT wiring method. I couldn’t find where they were tied together. The best solution I could come up with was to land both wires on one of the breakers. The circuit(s) fed bedroom receptacles, so not much load.

At the very least, it violates the parallel conductor rule, but I feel it’s now safer than leaving it the way it was.
 
I like the above ideas. But your other choice would be to take a couple outlets out, pull the wires off. Then just turn one breaker on. You'll find it sooner or later. If their is a crawl space or attic . You may be able to use a non contact tester on the cable.
 
I'd look at the last outlet someone replaced - they may have replaced a split receptacle with one that has the tab intact
 
Jraef said:
It HAS to be found and separated, because aside from the danger to a service person, if there is a fault, one breaker may trip and the other may not.
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Current will divide roughly evenly across the two breakers- its like a 30 or 40 amp breaker is protecting the wiring. Very dangerous.
 
Turn both breakers off and see what all items in the house go off. When you find that, and it happens to be different areas, start taking things apart in one of the rooms/areas one at a time. Turn one of the breakers on and check everything that was off. Keep doing this until you find where some areas are on and some off. Then it's just a matter of looking for splices that shouldn't be together. This could be very time consuming but should be done.
 
Little Bill said:
Turn both breakers off and see what all items in the house go off. When you find that, and it happens to be different areas, start taking things apart in one of the rooms/areas one at a time. Turn one of the breakers on and check everything that was off. Keep doing this until you find where some areas are on and some off. Then it's just a matter of looking for splices that shouldn't be together. This could be very time consuming but should be done.
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I actually solved the problem rather quickly on two occasions because the two that happened to be tied together were one of the lighting circuits and one of the SABC's. I had to turn off both a 15 and a 20A breaker in order to kill the circuit. Based on that logic, the very first place I looked was in a 2-gang combo switch/outlet on the countertop. And bingo, there was the illegal tie point! The homeowner didn't know what he was doing, so he tied all the neutrals together and all the hots together. Once I separated each wire to the appropriate circuit, everything worked normally. But there have been others that were a lot more difficult to track down.
 
I'm also glad you found it. You're lucky - you should go out and buy a lottery ticket. Thankfully, in your case, the wiring was on the same phase. The same thing happened to me once. There were 4 BX cables inside a 3 1/2" JB in a basement. One cable went to a receptacle on the first floor, the other three seemed to originate at the breaker panel. It took 3 breakers to shut the power off. I separated them and used only one to feed the receptacle. I went out and bought a lottery ticket but didn't win :-(
 
jeff48356 said:
I actually solved the problem rather quickly on two occasions because the two that happened to be tied together were one of the lighting circuits and one of the SABC's. I had to turn off both a 15 and a 20A breaker in order to kill the circuit. Based on that logic, the very first place I looked was in a 2-gang combo switch/outlet on the countertop. And bingo, there was the illegal tie point! The homeowner didn't know what he was doing, so he tied all the neutrals together and all the hots together. Once I separated each wire to the appropriate circuit, everything worked normally. But there have been others that were a lot more difficult to track down.
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the last few I ran into I also found very quickly, just started taking apart wiring at multi-gang switches, one only took 20 minutes from time I walked thru door to completion. And one I never even had to drive to, talked the DIY homeowner thru on phone! (the fact that he had created the problem probably made it easier for him to solve)
 
I had this issue in a kitchen. A remodeler had swapped out devices and added a jumper in a 2-gang from a (non-gfci protected) countertop receptacle to the lighting switch.

See it quite a few times in brand new homes where multuole people were pulling wire. Circuit would get double fed.

Best case scenario is if they are NOT on the same leg. If they are, you don't know there's a problem

240v dead short lets you know immediately
 
James L said:
I had this issue in a kitchen. A remodeler had swapped out devices and added a jumper in a 2-gang from a (non-gfci protected) countertop receptacle to the lighting switch.

See it quite a few times in brand new homes where multuole people were pulling wire. Circuit would get double fed.

Best case scenario is if they are NOT on the same leg. If they are, you don't know there's a problem

240v dead short lets you know immediately
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Had one of those dead shorts on a house the ropers did for a former employer. They had reset the GE breaker in their attempt to fix so many times, it no longer tripped.
 
I had some electricians once that pulled wires from a control panel to two different motors and somehow managed to run a phase from each motor starter to the wrong motor. They kept telling me there was something wrong with the motors because the motors wouldn't run and they kept swapping the leads at the motors to try to get them to run and they would not run unless both motor starters were turned on at the same time, Even though there was power at the motor.

Once they told me the part about both motor starters having to be on or neither one would run it was pretty obvious what had happened to me. Their boss told me there was no way that could have possibly happened when I suggested he check for that.

I had another control panel where they crosswired a one horsepower motor to a quarter horse starter and vice versa. The quarter horse motor starter tripped every time. Not real surprising.

It is not real hard to cross wire stuff.
 
If I had to list one, this would be one benefit to AFCI breakers. Neutrals are dedicated to the breaker/circuit so its not possible to double feed a circuit without the AFCI letting you know there's an issue. Nor can you accidently parallel neutrals in a switchbox with multiple circuits.

Like the OP said "Homeowner did the work" How hard can it be black to black white to white right?
 
Had one that took 4 breakers to shut off all power. The GC was moving some walls and needed to move some wiring. Found one line going into a crawl attic. Found a jbox covered by insulation that had all the circuits running into it. All neutrals were tied together.
 
Fred B said:
Had one that took 4 breakers to shut off all power. The GC was moving some walls and needed to move some wiring. Found one line going into a crawl attic. Found a jbox covered by insulation that had all the circuits running into it. All neutrals were tied together.
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Just solder all the wires to the bus and use the main to turn it all off 🤣🤣🤣
 
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