I found an outlet in my house that has two romexes coming in. Each cable has a red, black and neutral (and ground, but no issue there). The red and black are on separate circuit breakers. The two reds are tied together and on the top brass screw. The two blacks are tied together on the bottom brass screw. The tab between the two has been removed. The two neutrals are each screwed into the outlet on the proper side, tab intact. Not sure if the reason for this is a switched outlet, but I don't think it matters. Is it proper to have two separate circuits in an outlet that share the neutral? The outlet is properly grounded.
Unusual To Me Outlet Wiring- Two Hots on Same Neutral
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It's called a multiwire branch circuit. It's common in older homes. There will be less MWBC's in the future due to the requirements of fault protection and the way neutral current is monitored.
There is a code violation at this receptacle however. The neutrals should be pigtailed and not relying on the device for continuity.
There is a code violation at this receptacle however. The neutrals should be pigtailed and not relying on the device for continuity.
The blacks and reds are pigtailed. The neutrals, though, are each on their own screw, but the tab is intact. I would think this would be better than pigtailing and then using one screw, why would a pigtail be preferred? The circuit breakers are not tied, I was quite shocked when I through the one breaker, it turned off my test light and proceeded to jump in, only to be reminded not to assume both outlets are on the same breaker.
I'm wondering if I should figure out the two breakers in the panel and re-wire for a tied arrangement?
I'm wondering if I should figure out the two breakers in the panel and re-wire for a tied arrangement?
It's proper if there's 240v (and not 0v) between the red and black. The top and bottom sockets are on different circuits sharing a neutral, and both pass through, so probably there are more wired the same way. Is this a kitchen?
The two breakers should be vertically adjacent so that a nail, for example, would tie them together. (A nail isn't an approved method but it's a lot better than nothing).
Neutral pigtail is to prevent the shared neutral from being broken if the socket is disconnected, which would be a shock/fire hazard. Though this would not be an issue if both are always turned off together, so tieing the breakers together is more important.
The two breakers should be vertically adjacent so that a nail, for example, would tie them together. (A nail isn't an approved method but it's a lot better than nothing).
Neutral pigtail is to prevent the shared neutral from being broken if the socket is disconnected, which would be a shock/fire hazard. Though this would not be an issue if both are always turned off together, so tieing the breakers together is more important.
My townhouse was wired with MBC in 1976. When I replaced the FPE panel the inspector required the MBC circuits to be tied together. The electrician argued for it to be grandfathered but no go.
Personally I feel better with handle tied breakers. That way a circuit is totally dead.
Personally I feel better with handle tied breakers. That way a circuit is totally dead.
Very odd, with breakers thrown, I am measuring 60 ohms between hot and ground on one of the circuits and I'm seeing a bright flash come out of the switch when thrown (and hot, of course) and when plugging things in. I have not investigated, but for now, the circuit is kept dead.
My washer dryer plug is wired this way. From the neutral to ground you should measure about the same resistance since both wires go to the same buss on the primary panel.
From both hots I measure 240VAC. It was a cost saving measure in 1976 to run everything Multi Wire to avoid the cost of another neutral. I guess copper was expensive then.
From both hots I measure 240VAC. It was a cost saving measure in 1976 to run everything Multi Wire to avoid the cost of another neutral. I guess copper was expensive then.
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This is VERY common in kitchen counter receptacles in Canada.
If the wire is looped around the screw then it is not right. If it is the style where you screw a clamp down on the wires(like a GFCI) then most of those will except two wires under one screw.
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