circuit breakers 6

[Reesh14]

I was wondering if code allows more than one wire to connect to a single pole circuit breaker? I was told that there is a circuit breaker available that is rated for 2 wires.

A 100A 120/208v panelboard is being replaced and many of the circuits are being backfed into the new panel. The contractor found several existing breakers with more than 1 wire connected. He divided them so that each breaker on the new panel now only has one wire, but that doesn't leave any room for the new circuits that were scheduled to be fed by this new panel. I am trying to figure out if we can copy the existing wiring (have more than 1 wire for some breakers) or have to use breakers that are specially rated to do so?

Any advice would be appreciated. Thank you!

 

[jraef]

As far as I know, the NEC requires one wire per terminal on circuit breakers unless there is a specifically listed lug that provides for separate tightening on each wire. I know there are larger breakers that have optional "distribution lugs" which have multiple holes, each with their own set screw, but to be honest I have never heard of that for 1 pole breakers such as you would find in a 120/208V load center.

 

[dpc]

I think only one wire, but it would be covered by UL listing for the breaker.

 

[davidbeach]

It is per the listing, but many 15/1 and 20/1 breakers have a pressure plate terminal listed for one or two conductors. If it has a box lug it is likely to be single conductor only. Check with the manufacturer.

 

[dpc]

To state the obvious, each conductor would have to be fully rated for the breaker size, per NEC.

 

[DanDel]

The NEC 310.4 specifically states (with a few exceptions that don't appear to apply) parallel conductors only when 1/0AWG or larger, same length, size, insulation, terminations, etc., and when both end up at the same device.

 

[dpc]

DanDel,

That article applies if the intent is that the two conductor's ampacities be combined to satisfy the overcurrent protection requirement.

But I think what he is talking about is putting two fully-rated conductors under the lug and going to different places with each conductor.

 

[tommy75]

That would be one wire per lug. You can purchase tandemn circuit breakers from just about any panel manufacturer for Square D QO sreries the part number would be a QO 2020. Thats a single space breaker with two seperate circuits provided.

 

[Chaosiscash]

Davidbeach is exactly right. Many manufacturers produce single phase breakers that are listed for two conductors, and there is no code violation as long as the wires are sized correctly and going to different loads. Just check with the breaker manufacturer.

 

[DanDel]

dpc, my intention was to indicate where two conductors are allowed per the code, and it's only when they are parallel conductors per that article.

I don't think you'll find anything in the code specifically allowing or forbidding it. I would imagine that any inspector certainly wouldn't allow it.

 

[TestBeforeTouch]

The NEC in section 110.14 (A) says "Terminals for more than one conductor and terminals used to connect aluminum shall be so identified."

 

[SteveWag]

The following was copied from a Square D Tech. Bull.:

"Terminations
The 10–30 ampere circuit breakers have pressure plate terminals suitable for two-wire copper
terminations. QO-GFI 15–30 ampere and QO-AFI circuit breakers have pressure plate terminals
suitable for single-wire terminations. These circuit breakers are suitable for use with 60°C or 75° C
conductors."

I have done a lot of two-wires on a single pole breaker, it's no big deal, and no, the NEC says nothing about it.

Steve Wagner

 

[powerjunx]

SteveWag has good reference that's what product advisory emphasized.
Reesh14: We've been terminating circuit breakers more than 2 wires, but we've found out a hot spot and even a burnt out terminals whenever we routinely checks our panel through thermal scanning and visual inspection.
With this practice, like yours, we've reviewed and check the practice conformity against the standard with direct inquiry to the Square D(Schenieder) technical support. They had nothing to say about multiple termination and tappings but they advice us to use a bolts and nuts termination that disregards the aluminum allen-hex compression terminals which loosen over time and high thermal expansion that leads to overheating. With it, we never experienced such hotspots on terminal in conjunction with PdM schedules.






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