Parallel Neutrals?

[h1h2h3]

Came across a situation today and was wonder what your thoughts were on this.

Aside from an absolute mess, what would you refer to this as: paralleled neutral, shared neutral, or something else entirely?

Note: This is confusing, even when looking at it.

2 12/2's leave a panel and each hit a time clock. From the time clocks, 2 more 12/2's (load side) leave the time clocks and enter a junction box. Inside the jbox, the 12/2's connect to two 12/3's in this manner: the neutrals are tied together and the black from the 12/2's are connected to the red on the 12-3's. Those two 12/3's come from the panel where the blacks are landed on breakers and the reds are spliced with 2 the red's from 4 other 12/3's (one red from the jbox 12/3's are spliced with two other red's in the panel.) The blacks from the other 4 12/3's are also landed on breakers. All the neutrals are tied in to the neutral bar at the panel. Back at the jbox, the black from the 12/'3's are tied with the blacks from two more 12/3's, the neutrals are tied with the neutrals from the two additional 12/3's, and the reds from those additional 12/3's are connected to the blacks of two more 12/2's coming from the panel, and all the neutrals are tied together. No two pole breakers were used, no handle ties were used, but this is a much older instal and it's a possibility that this was a multiwire branch circuit venture gone horribly awry. It looks like they just pulled neutrals from anywhere possible and ended up mixing and matching neutrals from as many as 4 circuits at one time.

Needless to say, I didn't want to be the last one to touch this. I told the customer that unless they wanted to pay me to completely rewire these circuits, I would not touch anything on them or add anything to them. Good call I think.

Any thoughts on what this mess would actually be called or referred to by the NEC would be greatly appreciated.

Thanks

 

[Smart $]

Well your customer definitely has non-compliant parallel neutral conductors. May have breakers in parallel [240.8]. I'm also thinking he has multiple same-circuit neutral's landed in the panel, which lends to circuit conductor not running together, or originating in same equipment... but I can't seem to nail down the specific section which says a circuit neutral can originate in a panel and make its way back to the panel, land again on neutral bus, then continue with the circuit by connecting another neutral conductor to the neutral bus. outright not professional, but can't find a specific violation with that... other than where it amounts to a parallel conductor violation.

 

[h1h2h3]

I had no idea that was permissible, but when I think about it, coming in and out of the neutral bus for the same circuit isn't much different than a splice on any given parallel circuit. I would think though that this would mean that the ungrounded conductor would also have to re-terminate or be spliced in the panel as well. Otherwise, same-circuit conductors would not be running together. Also, I would think that you would need to have them landed on the same lug to avoid one neutral being removed while there is still unbalanced current on that conductor. In this instance, the exception under 408.41 would apply...was that the article you were thinking of?

"Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor."

 

[GoldDigger]

Well your customer definitely has non-compliant parallel neutral conductors. May have breakers in parallel [240.8]. I'm also thinking he has multiple same-circuit neutral's landed in the panel, which lends to circuit conductor not running together, or originating in same equipment... but I can't seem to nail down the specific section which says a circuit neutral can originate in a panel and make its way back to the panel, land again on neutral bus, then continue with the circuit by connecting another neutral conductor to the neutral bus. outright not professional, but can't find a specific violation with that... other than where it amounts to a parallel conductor violation.

Not looking at the formal NEC language, but just circuit theory, the two runs from one point at an outlet back to the neutral bar constitute a parallel circuit. And the two parallel conductors do not follow the same path, which would be a violation even if the size were large enough to allow paralleling.
By the same reasoning, the British standard ring circuit wiring is not legal under the NEC.

 

[Smart $]

I had no idea that was permissible, but when I think about it, coming in and out of the neutral bus for the same circuit isn't much different than a splice on any given parallel circuit. I would think though that this would mean that the ungrounded conductor would also have to re-terminate or be spliced in the panel as well. Otherwise, same-circuit conductors would not be running together. Also, I would think that you would need to have them landed on the same lug to avoid one neutral being removed while there is still unbalanced current on that conductor.

Permissable, perhaps. But it still amounts to being a parallel conductor smaller than 1/0.

In this instance, the exception under 408.41 would apply...was that the article you were thinking of?

"Exception: Grounded conductors of circuits with parallel conductors shall be permitted to terminate in a single terminal if the terminal is identified for connection of more than one conductor."

No... and no 408.41 would not apply because of the parallel conductor violation.