Is one circuit connected to two breakers safe?

Question

We redid our bathrooms and had an electrician come in and put in new wiring for outlets, heater/fan/lights and heated floors. He had to replace the electrical panel, because the house is older (1956) and didn't have enough space to accomplish the task. So he installed a new electrical panel. Everything was fine for a while.

Then the lights started to flicker and electronic devices started to pop on and off.

Then 1/2 the house started to lose power. No breakers were tripped.

We called the electrician and he said the power loss was probably coming from the pole and to call in the power company to check the line.

Power company came out, checked the line and determined it's something in my house that's causing the outage.

Since then the power has gone out for up to 24 hours at a time. Flickering lights signal the outage. Now being an old house they have most of the lights along one line. Dining room light, kitchen fan light and several outlets in our bedroom are on the same line (it's a ranch) on one side of the house, the other side has multiple fixtures and outlets as well. I went down to the electrical panel (surprise nothing labeled) to see which circuit breaker was causing the problem. Went up and down both sides of the panel, but not once did the lights or outlets go out. Finally I turned off one side of the panel (left) and then started to turn on breakers one at a time and discovered 2 separate breakers 6 down from each other combined, turn off the power to the lights and outlets along this line.

Now with the old box, no problems, electric did not flicker, nor did only 1/2 the house lose power.

Question, what did the electrician do and is it safe to be on 2 breakers like that until he can come out and look at the problem?

Thanks

Answer 1

Did the electrician replaced the Service panel only, or (s)he also worked on other things like adding junction boxes and ran new conduits? The problem of 2 breakers (let's call #1 and #7 connected to the same circuit (lights in this case) might not be at the Service panel, but it could be that he had mistakenly connected wire from #7 to the existing light circuit which already had been connected to #1 prior to this, at the new junction box. You need to trace down where the old lighting circuit connected to those #1 and #7 wires.

Answer 2

There is no valid way for two breakers to control the same circuit. Either through accident (as suggested above, poorly placed staple) or oversight (creating a direct splice between hot wires belonging to two different circuits), there is a short between the output of breaker#1 and breaker#7.

This is bad, because, even if it was done through oversight and insulation was not punctured, two breakers combined likely have a higher current rating than wiring in each circuit. For example, if each breaker is 15A, it would trip if you try to draw 15A from its circuit, before overloading the wire. If you have two 15A breakers in parallel, that effectively becomes a 30A breaker, which won't trip easily and overloading the circuit would result in melted wiring inside the wall (you can imagine the outcome).

To protect yourself until the issue is properly dealt with, I would suggest to keep one of the pair of breakers permanently "off".

The fact that your lights go out at random without any breakers tripped suggests that there's a loose wire somewhere in the circuit that feeds those lights. This may or may not be related to the problem of parallel breakers.

Does the set of lights and outlets which go out random match exactly with the set of lights and outlets which are controlled by two parallel breakers?

Answer 3

Question, what did the electrician do...

I ran into the same issue today. This might help someone else since your issue is likely solved.

A licensed electrician came and added some lights, switches and moved some circuits a few weeks ago for a remodel (no drywall/all wiring exposed). Today I wanted to move a switch from one wall to another and found I had to turn off 2 breakers to kill the single switch I was working on.

I started to unwire each switch and outlet on those 2 breakers and flip the breakers on/off and test with a non-contact voltage tester what was still hot until I found it. What I found was he ran romex from an existing hot in a four gang switch box to an outlet that already had another line running to it from the panel (makes no sense to me). I removed that additional run and everything started working normal.

Answer 4

Permitted? Inspected?

Usually a panel replacement would involve bringing the entire structure up to present-day code. For a remodel, reusing 1956 wiring would not pass inspection.

From the dialogue there are a couple notations:

1. Too many devices on a single circuit.
2. Sounds like existing wiring was reused. May be ok maybe not.
3. There is an arc fault somewhere.
4. There is a miswire or short between two breakers.
5. Possible neutral issue at the pole or new panel.

Answer 5

It is possible for 2 breakers to control the same circuit because you have 2 legs of 110 coming from the pole. Lets say leg one of 110 coming from the power company is labeled leg A and the other is leg B when combined you get 220V. If breaker # 1 is powered by leg A of the power coming into the panel and breaker # 7 is powered by leg A of the power coming in the panel and the 2 circuits have power meeting each other in an enclosure such as a junction box you could potentially have 2 separate breakers control two separate circuits at the same time. If you shut off breaker 1 the power would simply come from breaker 7 and if you shut off #7 while # 1 was on the power would come from breaker # 1 You would have to have both breakers off in order to shut down the circuits. It wouldn't short out because they are pulling from the same leg. and it would be a mess but you would have to find where the two meet and get it disconnected. Or if you knew what the two lines controlled and there was large enough conductor leaving the panel you could potentially remove one of the breakers and put them both on the same breaker. Another Idea would be just to shut off one of the 2 breakers but that could cause someone else in the future confusion. If one of the breakers was off at least you would actually have circuit breaker protection.