I'm going to swat the hornets nest and say yes, you can. I don't think you even need a 220v breaker. 2 single pole breakers can replace the 2 pole 30 amp breaker.
John
Member
I'm going to swat the hornets nest and say yes, you can. I don't think you even need a 220v breaker. 2 single pole breakers can replace the 2 pole 30 amp breaker.
John
Contributor
Yes, if you're sharing the neutral (Multi-Wire Branch Circuit) you need a 2 pole breaker. (That's the proper name for what you're calling a 220 breaker).Originally Posted by Dennis McDonaugh
Regards, Rod.
Contributor
Hi John, if he's sharing the neutral, it has to ba 2 pole breaker, not 2 single pole breakers............Regards, Rod.
Moderator
Maybe this picture helps?
multiwire branch circiut graphic.jpg
Member
Why?
John
Member
It's a code requirement, because if you shut down one breaker, you can backfeed voltage to what would otherwise be a de-energized leg.
Member
Not trying to argue, but where would the backfeed voltage come from?
I understand the need for the 2 hot leeds to be on different legs, and a 2 pole breaker would guarantee that.
John
Member
In the 2005 NEC, the 2-pole breaker requirement applied only if there were 240-volt loads or if any single device (like duplex outlet) connected to both phases. In 2008 this was changed so that all MWBCs require 2-pole breakers no matter how they are used. (NEC 210.4)
If there are any 240-volt loads on the MWBC and you open only one breaker, it will put 120 volts on the open phase via the load. The same can happen if you lose the neutral and there are 120 volt loads. While that may appear to be unlikely to happen, if someone has a floating neutral condition, opening one of the breakers could very well be one of the first troubleshooting steps an electrician or homeowner takes. An open neutral will exhibit bright lights and dim lights, and people will typically begin flipping breakers to protect those loads.
Member
OK, thanks, Rick. I once worked for an electrician wiring new houses and duplexes. A few times we would split a duplex outlet up and powered it from 2 breakers at kitchen counters. That way the outlet could power a coffee maker and toaster oven without tripping the breaker. We didn't use 2 pole breakers, but that was in the mid 80"s.
John
Member
You obviously haven't worked with many inspectors. I've seen inspectors make up rules on the spot. I challenged one who was about to cost my company and our client a lot of money and he just spun the written law to be interpreted so it fit the new rule he just made up. I have dozens of accounts like that and those who work in the construction business have countless more.
When working with an inspector, you have to have a feel for him or her and know when to back down. After you have established a good working relationship with the inspector, he or she usually works with you so as not to cost your or your company money unnecessarily. Those of us in the building trades know this and it's a more important tool in getting the job done than knowing the code verbatim.
A clause that popped up in more and more contracts over the years was that the sub-contractor not only had to meet the specifications laid out by the drawings and specs, but also was required to meet code. In other words, the architects and engineers no longer accepted responsibility that their drawings and specs met local code. That responsibility was being passed down to the general contractor. And the general contractor would pass that down to the sub-contractors. So anytime I was entering a new municipality, I would call the inspector and inquire about anything that I thought may be a sticky point before submitting our bid. Of course, I would first ask what code they follow. Rarely did I find a municipality that followed the NEC without having any addenda. But that first call to the inspector pretty much guaranteed our work would pass inspection.
From my experience and the experience of other construction professionals I've talked to over the years, you're always better off being diplomatic (and respectful) with an inspector than challenging him or her and standing firm on your beliefs. Whether I was working with the inspector as a foreman or project manager, I knew the best way to insure the jobs passed inspection was by having a good relationship with the inspector. The code is like a law book, it can be interpreted many ways and the experienced inspector knows how to use this to his or her advantage. And they love doing that especially when they think they are faced with a know-it-all. I've heard more than one say just that. Diplomacy is always the best policy.
Moderator
I think this thread has drifted way off topic. Time to move on, Folks. Thank you.
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