220 breaker

[Mike in Ohio]

Good friend asked me to help trouble shoot a wiring problem in his basement. He was convinced I helped him wire it (which means I wired it with his help) back about 1995. I remember helping frame it and hang but not finish the drywall. After about 10 minutes it was very clear to me that I had nothing to do with the wiring, I stay very much in my comfort zone with electricity. I have no clue what some of this was, including using a 30 amp 2 pole (220) breaker to power 2 circuits, I hope that makes sense to you experts. The actual problem is both circuits controlled 3 way switches, one controls the overhead lights and branches before the switch to power the bottom half of the receptacles. The second 3 way switch powers the top half of the receptacles so floor lamps can be controlled by the wall switch. Friend in question decided to replace switches and receptacles with a different color. when he was done the top (switched) receptacles didn't work. As I got into the mess it seemed that parts of both circuits shared a neutral, something I never would have considered 30 years ago, or even yesterday. At one point I shorted one of the circuits, it did not blow the breaker, but there was no power to that circuit after that.

Question is: is it possible that the breaker didn't trip because only one side was shorted, and the other side wasn't, but something melted inside the shorted 1/2 of the breaker causing the loss of power to that circuit but not the other.

The end result was I created a new circuit for the stuff that didn't work with its own neutral and ground, but the 220 breaker still bothers me, and I think I need to replace it with 2 15 amp 110 breakers, this is a bedroom.

If all this made sense, what do you all think??

 

[The Cobbler]

sounds scary
did you try switching the breaker off & reset it back on? and yes, a 30 amp is just wrong

 

[Norcal]

A 30A breaker is not suitable for normal branch circuits 15 or 20 ampere circuit breakers are required depending on the conductor size, since multi wire circuits have been mentioned a 2 pole breaker or handle ties on single pole breakers.

 

[wyliesdiesels]

Good friend asked me to help trouble shoot a wiring problem in his basement. He was convinced I helped him wire it (which means I wired it with his help) back about 1995. I remember helping frame it and hang but not finish the drywall. After about 10 minutes it was very clear to me that I had nothing to do with the wiring, I stay very much in my comfort zone with electricity. I have no clue what some of this was, including using a 30 amp 2 pole (220) breaker to power 2 circuits, I hope that makes sense to you experts. The actual problem is both circuits controlled 3 way switches, one controls the overhead lights and branches before the switch to power the bottom half of the receptacles. The second 3 way switch powers the top half of the receptacles so floor lamps can be controlled by the wall switch.

This is a mess waiting to happen. definitely not code permissive. I wouldnt be touching it. needs to be ripped out

Friend in question decided to replace switches and receptacles with a different color. when he was done the top (switched) receptacles didn't work. As I got into the mess it seemed that parts of both circuits shared a neutral, something I never would have considered 30 years ago, or even yesterday. At one point I shorted one of the circuits, it did not blow the breaker, but there was no power to that circuit after that.

Question is: is it possible that the breaker didn't trip because only one side was shorted, and the other side wasn't, but something melted inside the shorted 1/2 of the breaker causing the loss of power to that circuit but not the other.

no not possible. nothing in a breaker melts when there is a short. my guess is a poor connection on a switch, receptacle or splice, gave up the ghost.

The end result was I created a new circuit for the stuff that didn't work with its own neutral and ground, but the 220 breaker still bothers me, and I think I need to replace it with 2 15 amp 110 breakers, this is a bedroom.

If all this made sense, what do you all think??

should get rid of the MWBC- multi-wire branch circuit and the breaker definitely needs to be changed to 15 or 20a depending on the wire gauge. I highly doubt the wire is even #10 but regardless should not have a 30a breaker feeding 15/20a switches and receptacles.

 

[Norcal]

It really sounds like a rip it out & start over job.

 

[nadogail]

It really sounds like a rip it out & start over job.

There are some jobs that are doomed to failure because they were started by people with just enough knowledge to be dangerous.
Those jobs should be avoided unless all involved are willing to face up to their ignorance and are willing to rip it all out and start over.

 

[sparky 1971]

Is it possible that it wasn't a two pole breaker, but two single poles and a handle tie? That would explain the only tripping on one side. The 30 amp part is a no-no but a two pole or two single pole breakers with a handle tie is the way a MWBC is supposed to be connected now, but it wasn't a requirement in 1995. It's probably just two lighting circuits that happen to have three way switches and are in the same box.

 

[75gmck25]

Swap in a 20 amp dual breaker, which would be correct for an MWBC circuit with 12 gauge wiring.

One neutral and two hots (12/3) is fine for the MWBC at the panel end, but at there must be a junction where it breaks out into two 20 amp circuits. It is usually a larger junction box, with the 12/3 coming in and two 12/2 cables coming out. From there on you have two separate 20 amp circuits and they are wired like any other circuit.

It sounds like your friend did not mark the wires in the box when removed, and they may be connected to two different circuits coming in. He also complicated the wiring by requiring two three-way switches, which always gets a little confusing if everything is not marked correctly.

There are multiple ways to wire three-way switches, depending on whether the light is in the middle or at one end, and which box gets the power feed from the panel. It also possible that the power feed goes to the light or switched receptacle, not to one of the switch boxes.

- If its not obvious how its wired, I would first disconnect all the wires at each box, put a meter on each 12/2 wire coming in, and try to determine which wire is the power coming from the panel. You may even have to check the light fixture or wall receptacles to find it.

- Then use a multimeter (with the power off) to check continuity between the 12/3 wires and determine which one belongs to which three-way circuit. Basically, you need to isolate the one circuit for the MWBC and get it working.

- Look up online and get pictures to figure out how the three-way may be wired. It may take some experimentation to get it working, since you don't know where the lights are in the circuit (end, middle, etc.).

This may be one time to just call an electrician, since they work frequently with three-way switches and MWBC circuits. Its probably worth the cost of a trouble call.

 

[u2slow]

Obviously downsize the breaker. Then start troubleshooting.

Nothing wrong with a mwbc; there are simply more nanny-rules about them in the name of idiot proofing.

If it worked before, it can work again after fixing whatever failed.

 

[Mike in Ohio]

Thanks for all the answers guys, I disconnected all the switches and plugs and used a multimeter to see where each wire went, then hooked it all back up, with the exception of the non-switched side of the plugs I ran a new line to power them. I still need to replace the breaker after hearing all your advice.

Thanks again.