# 3-pole breaker feeding single phase panel



## Marshall175 (May 23, 2009)

3-phase 120-208 breaker feeding single-phase 120v panel. 

Is this NEC compliant?


----------



## Bob Badger (Apr 19, 2009)

Marshall175 said:


> 3-phase 120-208 breaker feeding single-phase 120v panel.
> 
> Is this NEC compliant?


Sure, just a waste of money.


----------



## Marshall175 (May 23, 2009)

wasn't sure, that's what Square-D sent...


----------



## drsparky (Nov 13, 2008)

I would say you are violating the listing. Square Ds are not just three breakers riveted together.


----------



## RePhase277 (Feb 5, 2008)

drsparky said:


> I would say you are violating the listing. Square Ds are not just three breakers riveted together.


Maybe not, but there are still three individual poles within the unit. What harm is there in using it, other than the waste of money?


----------



## drsparky (Nov 13, 2008)

If possible I would swap it out later; panels seem to fill up fast. They are expensive.


----------



## micromind (Aug 11, 2007)

I can't see any violation, but one of my biggest pet peeves is a single phase panel installed on a 208 wye service. It just screams 'incompetent hack', or 'cheap'. 

I understand a single phase panel on a 240 delta system, but on a wye; no way! If you've got a wye, install a 3 pole breaker, run all 3 hots, and use a 3 phase panel. It's not much more money, and it looks way more professional.

Sorry for the rant, it just irritates me to no end.

Rob


----------



## Larry Fine (Oct 24, 2007)

micromind said:


> I understand a single phase panel on a 240 delta system, but on a wye; no way! If you've got a wye, install a 3 pole breaker, run all 3 hots, and use a 3 phase panel. It's not much more money, and it looks way more professional.


There are thousands of apartment and condominium buildings that have 120/208 1ph panels in each unit.


----------



## RePhase277 (Feb 5, 2008)

Larry Fine said:


> There are thousands of apartment and condominium buildings that have 120/208 1ph panels in each unit.


Pretty sure Rob meant in a commercial or industrial setting. But you know that, you're just trying to build a post count:thumbsup:


----------



## MDShunk (Jan 7, 2007)

Larry Fine said:


> There are thousands of apartment and condominium buildings that have 120/208 1ph panels in each unit.


I agree. It's pretty much the only way apartments and condos are done. Nobody installs a 208-240 transformer, except for maybe something special like an elevator. Heck, that's even the way a lot of small strip mall stores are done if the a/c for each suite isn't over 5 tons per RTU.


----------



## mattsilkwood (Sep 21, 2008)

yea ive seen that in alot of places.


----------



## Bob Badger (Apr 19, 2009)

drsparky said:


> I would say you are violating the listing. Square Ds are not just three breakers riveted together.


I do not think you will find any instructions or labeling requiring the use of all poles.





micromind said:


> I can't see any violation, but one of my biggest pet peeves is a single phase panel installed on a 208 wye service. It just screams 'incompetent hack', or 'cheap'.


I agree 100%.


----------



## KayJay (Jan 20, 2008)

This probably isn’t the case in the OP's situation, but is worth mentioning for future reference simply because there are still some plug-in style 3-pole cb's available out there.
If the three-pole breaker is installed in a single-phase circuit panel, it could possibly be a listing violation per the '08 UL WhiteBook. 

CIRCUIT BREAKERS, MOLDED-CASE AND
CIRCUIT BREAKER ENCLOSURES (DIVQ)
3-pole circuit breakers are suitable for use only on 3-phase systems unless
marked to indicate otherwise


----------



## MDShunk (Jan 7, 2007)

It's still a 3 phase system, even if there's only two legs run to a particular panel. System is a word without a definition in the White Book or the NEC


----------



## KayJay (Jan 20, 2008)

MDShunk said:


> It's still a 3 phase system, even if there's only two legs run to a particular panel. System is a word without a definition in the White Book or the NEC


The reason I brought it up was because the OP never mentioned if he was feeding from a 3-phase system. He simply stated 120/208[?] 3-pole breaker feeding a single-phase panel and I think it was presumed to be in a 3-phase system.

Something else worth noting is that the Siemens 3-pole type BL, bolt-on circuit breakers I stock have a straight 240V rating, not a 120/240 slash rating. The 3-pole SQD cb's that I have used in the past also had a straight 240V rating, but this is not to say that they are all that way.
Without researching this matter further, I would initially have to assume that these 3-pole breakers were listed to supply only 3-phase loads.


----------



## drsparky (Nov 13, 2008)

KayJay said:


> The reason I brought it up was because the OP never mentioned if he was feeding from a 3-phase system. He simply stated 120/208[?] 3-pole breaker feeding a single-phase panel and I think it was presumed to be in a 3-phase system.
> 
> Something else worth noting is that the Siemens 3-pole type BL, bolt-on circuit breakers I stock have a straight 240V rating, not a 120/240 slash rating. The 3-pole SQD cb's that I have used in the past also had a straight 240V rating, but this is not to say that they are all that way.
> Without researching this matter further, I would initially have to assume that these 3-pole breakers were listed to supply only 3-phase loads.


I will go with that.


----------

