What the heck does "the neutral won’t ring back to the panel" mean? That you have an open neutral in a MWBC? That's a hazardous situation.

Wait - FIVE MWBCs? For goodness sake, WHY? That's a specialized wiring technique for specific situations. It's sometimes used for kitchen counter receptacles, for example, but even there it's not always the better choice. I've been wiring my own homes for almost 50 years now, and I've never installed a single MWBC.

I'm all for education and DIY, but Gallagher, you're scaring me with your posts here. You should be scaring yourself, too.

Just to clarify, I didn’t wire the place with 5 MWBCs that’s how it was done in 1990. Per 2017 Nec code what I did do is replace hazardous single pole breakers with doubles with required AFCI in living/sleeping areas. There is no open neutral. All neutral wires are working properly. I ring these breakers because it is tough to tell which of 5 breakers is tripped. No visible indication on breaker. Maybe the bar is moved slightly to a soft trip position. Also the original installer used two wire color patterns, black, red, white and yellow, blue, white so I can’t go by wire color at the outlet.

I was asking for help to figure out why 1/2 of a 2 pole breaker would go out unprovoked. Both phases appear energized at the panel yet only 1/2 of each affected outlet works. I do appreciate your concern. Help needed and appreciated.

You've got one of two problems: an overload or a ground fault. If it had been an arc fault, you'd have gotten the AF indicator on the breaker lit.

My guess is you've still go something miswired. If the neutral touches a ground, the old standard breaker wouldn't trip. GFCIs and AFCIs will. If the neutral touches ANY other circuit neutral (or ground), it will trip. If the hot wires touch any other hot wire it will trip. Obviously if the hot wire touches a grounded conductor it will trip.

You are going to have to carefully examine EVERYTHING connectded to that breaker and stop just guessing and poking at it with a stick. Wiring colors by and large mean SQUAT. The only thing that the code requires is grounds and neutrals be green/bare and white and those colors not used for anything else. I spent an afternoon of head scratching one day trying to replace some three-way switches when I found that there was a hidden splice in the circuit where the red and black had been swapped.

Thanks for clarifying the situation. It still seems odd to me that your house was wired that way, and especially so if the MWBCs were wired with 2 single breakers each. That makes me suspect that your house was wired by a clueless amateur, and wonder what other hazards might be lurking inside your walls.

However, I still don't understand your use of the word "ring." Maybe someone else knows it, but hat's not a term I've encountered in electrical wiring. "won’t ring back to the panel"? "I ring these breakers"? Sorry, these phrases tell me nothing. "The problem is 1/2 of an outlet has quit working." is also a little unclear. Do you mean one receptacle of a duplex that's wired with one receptacle on each side of the MWBC?

Following up on Ron's excellent post, IIRC your house is wired with conduit. Hot wires can be any color except green, white, or light grey -- unless your house really was wired by a dunce, in which case,it's anybody's guess what the wire colors might mean.

I don;'t think so. My tract house in Virginia was wired up with lots of MWBC on single pole breakers. Handle ties/double pole wasn't required until fairly recent versions of the code.

Here’s what I mean by ring the panel. If I what to test continuity and I’m not sure which breaker is the problem I shut down the breaker and at the outlet I ground the neutral on the conduit. Then at the panel I clip the black probe from my multimeter to the frame, set my meter to “ ring” ohms then probe with red lead the neutrals until I hear the Ring, Ring I’ve also heard guys say “ ping the panel. “

DavidR, Your understanding of my vague 1/2 outlet has quit is correct and said so much better than myself.

Right, I’m not actually sure how I picked that up. What should I say to be more clear?

This thread is all over the place. How about back to the problem???

• The problem is 1/2 of an outlet has quit working.

I assume that you are saying that you have a duplex receptacle and one outlet works and the other doesn't?

Have you taken the receptacle out to see how it is wired?

IDK - maybe somebody snuck into your house in the night and broke off the jumper tab on it???

You’re right the tab is broken because this is a MWBC. I think Ron may be right that I might have mixed up the wiring on two breakers. Specifically I have positively identified the neutral and 1 pole. I’m not totally sure how to identify the accompanying 2nd pole wire. Please guys help with this. Appreciated