No Breaker Shuts Off Circuit


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Old 03-21-24, 04:17 PM
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No Breaker Shuts Off Circuit

We're getting a place ready for rental inspection. I found out that NO breaker shuts off certain outlets. There is no sub panel. We had to shut the main off in order to replace a few outlets.What I did find was 2 breakers, via their wire screw terminations, remain live with respect to the panel neutral when I shut them off.

So I figured the breaker was bad and stuck in the on position, but no that's not the case. I took the breaker out, and isolated it. The continuity when on is ok, and no continuity when off is good.

But wait it gets worse. I took the wire off of the breaker and strangely enough there is 120 volts on that wire with respect to the neutral in the panel. Obviously this is a bit freaky. Suggestions on where I should start and what the heck is going on are appreciated. Thanks!
 
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Old 03-21-24, 04:34 PM
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Your statement about the main breaker was not 100% clear. Does turning off the main breaker kill power to everything, including the two problem circuits? If it does then the problem is somewhere in the wiring causing two circuits to be connected (skip to the next paragraph). If the power remains on then someone in the past may have done illegal wiring to steal power (call an electrician).

Plug a radio or light into a problem circuit. Turn off the problem circuit breaker. I assume the problem circuit is still energized and the light/radio remain on. Then one by one go through the other breakers turning them off and see if you find a breaker that kills the problem circuit. If so then somewhere those two circuits are connected.
 
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Old 03-21-24, 05:18 PM
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I assume you mean no *single* breaker turns off the circuit. Meaning two circuits are accidentally connected together. Any electrical box where the two circuits meet could be the location of the wiring error.
 

Last edited by Luke M; 03-21-24 at 05:30 PM.
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Old 03-21-24, 05:39 PM
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For clarity: Only the main breaker shuts off the circuits that won't shut off via any single breaker.

Could you please explain, even draw if possible, how "2 circuits connected together" are causing what I've described.
 
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Old 03-21-24, 06:04 PM
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A panel has two legs of power.... A and B. The breakers alternate as they go down.
1 ----- A ----- 2
3 ----- B ----- 4
5 ----- A ----- 6
7 ----- B ----- 8
Your two circuits must be both an A bus or a B bus.
If one was on A and one was on B ..... you'd have a 240v direct short.


 

Last edited by PJmax; 03-21-24 at 06:23 PM.
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Old 03-21-24, 06:11 PM
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Yes thanks. So I am aware of the A and B legs of power, and how they alternate.

What I don't understand is how I was able to remove a 15 amp breaker's feed wire from it's respective breaker and measure 120 volts on it with respect to panel neutral bus.....or how to go about troubleshooting and correcting the condition of this condition....humor only....thanks!
 
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Old 03-21-24, 06:15 PM
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If the hot wires from two different breakers get connected together somewhere down the line then in essence you have one circuit being fed by two breakers. So both breakers need to be shut off to kill the power to the cross connected circuits. Think of it like connecting two water hoses from two different spigots with a "Y" connector to a single hose. To turn off the water now coming out of the single hose, both spigots have to be closed. If you remove one hose from one spigot you'll have water coming out from the other spigot beiing open, hence the power on the wire you removed from the one breaker.
 
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Old 03-21-24, 06:29 PM
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I clarified my diagram.

It will not be easy to locate.
You will need to make a list of everything affected.
If there are two distinct areas.... see what is in common.

If both wires are black.... I'd doubt the problem would be at a receptacle.
Doubtful it would be in a place like split kitchen receptacles.

Most likely location is where there is switches or switch and receptacle.
A typical problem is combining black wires at switches from two circuits.
 
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Old 03-21-24, 08:15 PM
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Another way to find the breakers in question:

Turn off all breakers (except the main breaker up top).

Turn on just one breaker at a time and see if it energizes that circuit or outlet. Then flip that breaker off. A radio plugged in upstairs and turned up loud might help reveal the problem as you stand in the basement flipping breakers.

When you are done, turn on all breakers (minus any that you might be working on or you want to be off). Then check all refrigerators and freezers to be sure they are running before you go on to the next activity.
 
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Old 03-22-24, 01:59 AM
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Great. It's starting to get a little more understandable--but not fully sunk in yet.

Presumably this is a potentially dangerous condition?
 
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Old 03-22-24, 04:07 AM
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Hi, why not remove the conductor from the problem breaker, with a tester from it to neutral , turn off each breaker until the the power is off , then determine what is on those circuits , somewhere there is a cross connection, luckily they are on the same phase.
Geo🇺🇸
 
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Old 03-22-24, 06:30 AM
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OK thanks. I was ready to throw in the towel, but now it's getting clearer....(and bear with me I'm not super smart with translating instructions, I just have a lot of intelligent help as they say.)

So if I understand...there are 2 hot wires... each one is on same panel leg, but on different breakers?
And those 2 hot wires are wrongly joined somewhere? Is this what I am dealing with...?

If so then those 2 hot wires may be on say, the common to a dual switch? Or might they be even wire nutted together? Or...?

Then when I find them would it be correct to separate their respective neutrals from each other?
 
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Old 03-22-24, 06:57 AM
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Yes, I think you are understanding the situation.
 
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Old 03-22-24, 10:38 AM
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"Then when I find them would it be correct to separate their respective neutrals from each other?"

Yes, if connected. At this point all you know is the hots are wrongly connected. The neutrals are not necessarily connected.
 
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Old 03-22-24, 10:42 AM
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Someone modified something at some point without realizing. So look for any switches or receptacles that have been changed or upgraded recently.

Possibly at a set of switches. One circuit for outside lights and another for the hallway light, each going to their own switch and then off to the lights. They were supposed to be kept separate, but someone joined the two incoming hot wires together, thus wiring the two breakers together.
 
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Old 03-22-24, 01:39 PM
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As I mentioned.... concentrate on affected switch locations first.
There wouldn't be a reason to have two circuits at just a receptacle.
I had eliminated split kitchen receptacles as they'd be on opposite legs.
 
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Old 03-23-24, 06:07 PM
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Thanks for all the great replies! Now some adjacent thoughts...

First, in the past, I've never liked seeing 2 breaker circuits in one device box--always struck me as an invitation for trouble. Now I see why. When changes are made down the road, well meaning DIYers and even some apprentices I'm afraid can easily mistake that all the blacks 'should' go together except for the switch leg wires.

Plus what I'll now call Russian breaker roulette. Take the above situation, and then panel work is done where a new breaker is added--involving shuffling some existing breaker positions. The result can be that the 2 tied together circuits are now on opposite legs--then presto 240 volts at the device box.

I imagine the same thing can very easily occur when I new panel is installed. How do you guys account for this potential scenario?? My work ethic has always been to figure out what can go wrong and make sure THAT doesn't happen. (I'm glad I've learned something new to add to that ethic)

And while I'm on the going wrong topic...having somebody that improperly created a multi-wire circuit using 2 single pole breakers--especially when they're not near each other--instead using a 2 pole breaker. I've seen this one also.

How do you guys account for this kind of stuff? (ps I suggest if you are new to this thread please read it from the beginning for background
 
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Old 03-23-24, 09:57 PM
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Typically a multi wire branch circuit was just connected to two adjacent breakers.
The problem with that is it's possible to turn off one breaker killing one circuit but leaving the other live.
Now code requires a two pole tied handle or a 220v breaker. Turning that off kills both circuits.

Multi wire branch circuits were a way to save money by sharing a single jacket and neutral.
A MWBC is on a three wire cable so that there would be a hot red and hot black.
A MWBC shares a common neutral. The neutral handles the imbalance.
That's why it's imperative that the two circuits are on opposing buses.

The only place that I've ever used them at is split kitchen receptacles.
I would install a 4" square box with single mud ring at one location and send the two circuits out of that box.

Multi wire branch circuits on non adjacent breakers are a problem.
That's why in your case it's not a MWBC because you have two black wires in two breakers.
 
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Old 03-24-24, 04:30 AM
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Got it. I understand the multi-wire situation.Question is--when panels are changed or breakers are shuffled, is there a way, in advance, to test or account for the problem, at device boxes, of incorrectly joined hot wire pairs on separate breakers?

While it sounds like a slim chance, it also sounds like a heck of a liability if this incorrectness doesn't become evident.
 
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Old 03-24-24, 02:53 PM
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If it's a three wire circuit..... certain precautions are taken.
A situation like yours would not show up unless the circuits were on opposite buses which would create a short. There would not be any way an electrician would know of a problem like you're having.
 
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Old 03-25-24, 12:40 AM
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Many DIYers when trying to shut off a circuit for receptacles thinks that it would be only a single pole breaker powering the circuit since it is 120v. However, being misleading in that fashion, a MWBC is usually installed on a two pole 240v breaker (or two single pole breakers with a tie bar) which most DIYers would not know to check. So they flip all single pole breakers off and none kill the circuit because it is a MWBC powered by a two pole breaker. Then they just shut off the main breaker instead which of course kills the two pole breaker.

 
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Old 04-09-24, 04:48 PM
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OK so here is how I solved the original problem of the light needing 2 breakers to shut it off. What I found appeared to be 2 switch loops, each on a dual switch from different breakers, each controlling its own light.

Once I broke the common tab on the dual switch...everything in the house appears to be working fine. This drawing is how I understand it. Does this make sense?

 

Last edited by PJmax; 04-09-24 at 08:16 PM. Reason: reoriented pic
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Old 04-09-24, 08:18 PM
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Yes.... a dual switch can be used as two switches with one common hot or as two switches with different hots when the hot jumper is removed.

That's why I mentioned check switch locations.
 
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Old 04-10-24, 12:58 PM
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Oops, please bear with. The last drawing I posted to verify things was actually wrong. What I wanted to depict and confirm as the wrong wiring set-up and the solution being to remove the common jumper is in this picture.

 

Last edited by PJmax; 04-11-24 at 08:33 PM. Reason: reoriented pic
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Old 04-11-24, 08:36 PM
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You posted the same picture twice.
Yes.... the jumper is removed and the circuit works correctly.

If that was me.... I'd leave a little note in that box or written on the plate that there are 2 circuits there.
 
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Old 04-12-24, 06:01 PM
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Yes I did put a note on the back of the cover plate. And thanks for the suggestion to look at the switches first, which I did. First thing I noted was newer dual switches in an older house...so that's where I looked first and found the joined hots from different breakers.

Alas though...different drawings. Original one was incorrect. The latter one is the corrected version.



How it should be depicted.


Original drawn incorrectly
 

Last edited by Gen; 04-12-24 at 06:13 PM.
 

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