2 Pole Breaker for 1 Pole Circuit

Status
Not open for further replies.

ClemsSC7

Member
Location
Anderson
Hello,

I cannot find the code that supports the allowable usage of a 1P 20A circuit on a 2P 20A Breaker.

Situation: Customer has existing 220V 20A 2P equipment. Customer's equipment installer removes one leg from the existing 2P 20A breaker and re-tapes, re-labels one wire as a neutral and lands on the neutral bar. The equipment is hardwired. Customer's equipment installer re-labels the same wire as a identified neutral (same as in the panel) and lands it on the neutral connection in the equipment. The existing 2 Pole breaker now has one leg being used as a hot and nothing on the second leg. The Customer's equipment installer tells the customer that he has it wired to work but it isn't to code because it is being fed by a 2P breaker and it should be switched to a 1P 20A Breaker.

Customer calls me, I go look and see what has happened and I explain to the customer that it is legal per code (I'm fairly certain) but it is simply wasting a potential space in your panel. I told them I'd cite the code but I cannot find anything 100% like it.

NEC - 240.15 Ungrounded Conductors
(B) Circuit Breaker as Overcurrent Device: Circuit Breakers shall open all ungrounded conductors of the circuit both manually and automatically unless otherwise permitted in 240.15(B)(1), (B)(2), (B)(3), (B)(4).

I'm not violating this, is that what I can cite to be in compliance?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
There's is nothing in the NEC that says that you cannot use a two pole CB with a conductor connected to only one pole.
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
The answer is there is nothing in the NEC that says you can not use one leg or phase of a multi pole breaker, so it is fine but here is a minor problem, if the conductors are not part of a cable assembly they can not be re-identified as a neutral below a #4. Would I worry about that, heck no.

Roger
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
The answer is there is nothing in the NEC that says you can not use one leg or phase of a multi pole breaker, so it is fine but here is a minor problem, if the conductors are not part of a cable assembly they can not be re-identified as a neutral below a #4. Would I worry about that, heck no.

Roger

Not to be a worry wort but I would be concerned about re-identifying a wire in small size like here. Someone is bound to screw it up in the future.

I've seen it happen. Dead short , found someone had landed the black wire on a ground once.
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Not to be a worry wort but I would be concerned about re-identifying a wire in small size like here. Someone is bound to screw it up in the future.

I've seen it happen. Dead short , found someone had landed the black wire on a ground once.
This is where due diligence and "qualified" need to come together. If I see a small conductor has been re-identified I will need to find out why before I start landing it on different places.

Roger
 

MAC702

Senior Member
Location
Clark County, NV
I think the only thing in the NEC that might apply would be if the manufacturer of the breaker said you can't do it in the instructions. As noted, there is nothing electrically wrong with it (assuming a normal breaker.)
 

kwired

Electron manager
Location
NE Nebraska
I think the only thing in the NEC that might apply would be if the manufacturer of the breaker said you can't do it in the instructions. As noted, there is nothing electrically wrong with it (assuming a normal breaker.)
You could run a MWBC with no load connected to one of the poles - still sort of have same thing as far as the breaker is concerned.
 

480sparky

Senior Member
Location
Iowegia
Not to be a worry wort but I would be concerned about re-identifying a wire in small size like here. Someone is bound to screw it up in the future.

I've seen it happen. Dead short , found someone had landed the black wire on a ground once.

If Bozo the Electrician looks at a black wire wrapped in white tape and wonders why it's landed on the neutral bar, then Bozo should do something else for a living.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
I think the only thing in the NEC that might apply would be if the manufacturer of the breaker said you can't do it in the instructions. As noted, there is nothing electrically wrong with it (assuming a normal breaker.)

As I remember, all UL 489 Listed multi-pole breakers have been tested with fewer than all poles being loaded (i.e. 2-pole as 1-pole, and 3-pole as both 2-pole and 1-pole).
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
This is so obvious to me. If there is a short between one hot wire and a neutral or ground the cb will trip regardless if there are 2 poles connected. It would not be any different for overcurrent.
 

kwired

Electron manager
Location
NE Nebraska
As I remember, all UL 489 Listed multi-pole breakers have been tested with fewer than all poles being loaded (i.e. 2-pole as 1-pole, and 3-pole as both 2-pole and 1-pole).
If not we wouldn't be able to use them for feeders or MWBC's where the load isn't guaranteed to be balanced between poles at all times.
 
Status
Not open for further replies.
Top