Question for the electrical gurus on the board. Are all breakers that are rated for 2 wires marked as such on the breaker?
Thanks Larry. I’ve seen you post these pictures before. Obviously the clamp gives the impression of 2 wire capability. And the bottom picture actually says 2-wire capability. Does the breaker in the top pic say it somewhere that is not visible in the pic?
Typically, on the side of the breaker, Ryan.
I should clarify the reason I am asking. In my area, Square D is the most common found. But earlier this week I came across an ITE panel with ITE breakers. One was double tapped. ITE is no longer around, apparently swallowed up by Siemens. The Siemens equivalent of the breaker does not list or show 2-wire compatibility. The terminal clamp on the breaker did not imply 2-wire compatibility. But it would be nice to have an easy go/no-go reference. Google says the breaker should show 2-wire compatibility if present. Thus the reason for my question, do all breakers have 2-wire compatibility listed on the breaker itself? And a follow up, is this compatibility shown in a place that can be seen with the breaker installed?
The Square D QO breakers have a small graphic on the side of the CB that isn’t really visible when installed. Without knowing for sure those CB’s would need to be removed to confirm that they are listed for two conductors. And just looking at the CB might not be much help either, this commercial style CB looks perfectly fine with the termination of two conductors but there is nothing on the CB or in the listing that states it is acceptable for use with two conductors.
Thanks, Rob. 
Thanks Rob. So that leaves me wondering, if the manufacturer’s documentation doesn’t specifically say 2 wire compatible, does that mean it is not? And furthermore, if the manufacture is no longer in business, do we just use our best judgement? That question is somewhat rhetorical because I know we cannot just “guess” at what is allowed.
In your opinion, is this statement correct? If a home inspector observes a “double tap” and cannot verify the CB is rated for two wires; then it should be evaluated for verification or correction.
And second, is it true that only Square D and Cutler Hammer made two wire CB’s?
Thanks in advance.
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Great questions Brian. I couldn’t have asked them better myself!
Just to err on the side of caution I call them out. Eliminates the debate with the “dads” who like to follow along and try to show me up.
That and I just don’t like the practice. Too easy to overload them that way and it’s not necessary if there are extra slots for CBs. If that’s not enough, maybe it’s time to upgrade the panel.
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Must be easy to spend other people’s money by calling out something every time instead of only calling it out when it is wrong. There are not that many listed for two that it would be hard to remember.
Right, but those “two” also have breakers that are not rated for two wires. So, if you see a Square D or Cutler Hammer with two wires, it does not automatically make it ok. Therefore, if you cannot see the markings without removing the circuit breaker you best call it out and spend someone’s money. Because an improperly double tapped breaker is a fire hazard.
Square D QO circuit breakers accept two conductors so if those are present there is nothing to call out. Regarding CH I’m not familiar with those. There are so few CB’s that are listed for two condcutors it shouldn’t be difficult for someone to generate a list of the brands and types and call out whatever is not on the list.
IMO it would be pretty embarrassing to call out a Sq D QO circuit breaker because those have been around for 50+ years and it should be known that they are code compliant with two conductors.
I guess I need to learn how to identify these 2 wire breakers better. But, I thought we determined some were not identifiable without removing the breaker. I am doing my best here to sort this out.
The CH ones have a wedge that compresses the conductors, one on each side.
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It helps to familiarize yourself with the features of the handful of brands out there. It isn’t that hard. The other complicator is to familiarize yourself with what your AHJ likes to see. Around here, most of our AHJs don’t allow two wires on the breakers designed for two wires so it is a call-out regardless.
Is that a local NEC amendment or do they just decide to make up their own code?
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My guess is if they don’t allow it, then they don’t have to figure out if it is proper or not!
Typical ignorance of AHJ’s.
They make it up. I’ve said this on some other threads, but the chief of building inspections in one of our municipalities told me a few years ago, “We like to use common sense when we apply the code.” I said that is great, but common sense is subjective. He said, “True, but I am the one making the decisions.”