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Breakers that could take 2 wires under one screw

14K views 25 replies 14 participants last post by  Michael Thomas 
#1 ·
I heard that their are some circuit breakeres that could take 2 wires under one screw. Not sure if i heard right or wrong.

How can you tell if the circuit breaker can take 2 wires under a screw? Would those breakers be some push in style breakers or screws? What would be printed on the breaker saying its capable of taking 2 wires under a screw?
 
#4 ·
Never heard of Commander, good luck.

Current NEC says one wire per screw......Unless you are referring to Tandem breakers that have TWO screws and can take two wires....I think this is what you heard.
 
#5 ·
Current NEC says one wire per screw......Unless you are referring to Tandem breakers that have TWO screws and can take two wires....I think this is what you heard.
got a code citation for that? Last I knew, code states that you can only put what the device is rated for. If the breaker is rated for 2 wires, there is nothing to prevent such to my knowledge.

latinomusician The manufacture of my panel is "Commander"
what country are you in? I am not familiar with the brand. When searching for the name, I see references to Canada. If you are in Canada, the rules would be based on Canadian codes. There are a couple knowledgeable guy from Canada that post here so hang on for them to catch this and respond.
 
#6 ·
My mistake. Its a rule of thumb around here i guess. But you are right about rating. NEC does say that any breaker rated for more than one termination SHALL BE IDENTIFIED AS SUCH.

I would just wirenut the two together with a pigtail myself...
 
#8 · (Edited)
Some breakers are designed to accept 2 wires under 1 screw (double-tapping). The manufacture Square-D is such.

Actually, I think the ONLY manufacture that designs their breakers to be double-tapped is Square-D so that makes it pretty easy if your panel ain't Square-D. Square-D breakers have 2 openings for wires.
 
#9 ·
Also insert the wire end that is straight for the last 1/2 inch. Screw down the fastening but not far enough to keep the wire from wiggling a bit. If there are no grooves or fins or pressure plates to keep the wire from slipping out from under the screw even partially, then the terminal cannot take two wires under that screw.
 
#10 ·
Ive got a breaker on my air handler that has two wires from it. Its as large as a main breaker and has really large plates holding the wires in. It looks like it should take two wires..... Of course, the people that put them that way are the same people that ran romex across my roof to the heat pump and rotted the insulation off so.... :whistling2:

Shane
 
#12 ·
It is against code in Ontario to double tap. Maybe what you are thinking of is a mini breaker. Takes up one spot on the panel but has two taps (and two toggles). I've seen plenty of those, but not sure if Commander makes them.

Just on a different note...why is it when you go to the box stores you have to walk all the way to the electrical aisle to see the chart for the breakers, then walk back to the cashier to get it? Can they not put a chart up front?:laughing:
 
#14 ·
I believe the issue is a mechanical one. If you have two wires in the breaker it's less likely that the screw gets a good grip on the wire. If the wires are stacked then the screw won't go down far enough, then if the wires move they'll become loose. Remember, it's ok to have two "circuits" feed into one breaker by having the two runs and a pigtail under a wirenut and then having the pigtail go into the breaker -- so it's not likely an electrical issue.
 
#17 ·
if its not ul listed for use in a different manufacturers panel it will not pass.
 
#18 ·
Where else are you gonna use a QO breaker but in a QO panel???

And YES, it WILL "pass". Not that it is done very often at all, those breakers are designed for up to two conductors.
 
#20 ·
not in a commander panel it won't. Square D does not seek UL approval for their breakers in other brands of panels. So, no listing, no using.

I know cutler hammer has a line of breakers that are "classified" to use in various other brands of panels, including Square D homeline.

CH actually had their breakers UL tested for use in those panels.

So, the question of "where else you going to use a SqD hom breaker?" is answered with only a SqD hom panel, if the question was asked of a CH BR breaker, the answer could be:

Crouse - Hinds
General Electric
ITE / Siemens
Murray
Thomas & Betts
Square D Homeline
 
#22 ·
waldenL

in regards to your statement, "...it's ok to have two "circuits" feed into one breaker by having the two runs and a pigtail under a wirenut and then having the pigtail go into the breaker", what is the limitations there?

wire sizes and breaker capacity? can 2 20 amp circuits be hooked to a 20A or does it need to be 40A?

thanks
 
#23 ·
can 2 20 amp circuits be hooked to a 20A or does it need to be 40A?
There's a reason I quoted the word circuit in my post. Everything downstream of that breaker is one circuit. If you take two 20A "circuits" and connect them into one breaker, no matter how you do it (two wires on one breaker, wirenut in box, junction box, etc) you've created one 20A circuit with more stuff on it.

You could not connect two 20A "circuits" to a 40A breaker! Most likely the two 20A circuits would be run with 12ga wire. If they're hooked to a 40A breaker the breaker would not trip until more than 40A were pulled through it, but the wire is only rated for 20A.

Think of it this way, whatever the smallest wire is in the circuit dictates the max breaker for the entire circuit. If you had 10 receptacles run off a 12ga run you could have a 20A breaker. But add a single foot of 14ga wire at the end of the run (say to add an 11th receptacle) and now you've got to back that off to a 15A breaker.

Sorry for any confusion.
 
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