2008 NEC - 120V and 240V receptacles on the same MWBC?

ScottR

Hi All,

The 2008 NEC is adopted in my area, and I've been studying the Code.

210.4(C) says that MWBCs can only supply line-to-neutral loads, but Exception 2 says that L-to-N loads are not required if both ungrounded conductors are on a common trip breaker.

210.4(B) says that all MWBCs must have both ungnd. conductors on a common-trip, so it seems that all MWBCs under code would meet the exception above.

So am I right in surmising that I could have a 3 gang box fed by a single MWBC with 3 receptacles, each wired like this:

L1-N (120V)
L2-N (120V)
L1-L2 (240V) or L1-L2-N for a 4-wire 120V/240V receptacle.

I'm asking because I'm planning on redoing the electrical in my garage, and I figure that would give me the most flexibility on how I use some of my circuits in the future. I just think I might be missing something that prohibits it..

Speedy Petey

Yes, under the 2008 NEC all MWBC's require a common-trip breaker.

Yes, what you propose is fine.

I have to ask, are you absolutely sure your area is under the 2008 NEC for residential? I know your area well but have not lived there for quite a while. I was under the impression that ALL one and two family residential dwellings in NYS followed the 2007 NY Residential Code.
There are some very distinct difference between the two.

__________________
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.

ScottR

Thanks for the quick response, Speedy.

I'm 95% sure that the 2008 NEC is in force. The Town of Oyster Bay code is online, and in regards to electrical standards it says:

A.All new electrical wiring or installations or extensions of or alterations or removal of existing installations shall be made in conformity with the requirements of the National Electrical Code, being particularly the latest edition of the National Fire Electrical Code in effect at the time thereof, as recommended by the National Fire Protection Association, except where the provisions of this chapter or any other provisions of this Code or other ordinances of the town shall differently prescribe, in which event compliance with the provisions of such provisions of this Code or town ordinance shall be recognized as proper compliance with this chapter.

The town code has very few specifics itself about electrical installations; it prohibits Al wiring 4 AWG and smaller, prohibits NM cable in commercial, etc.

This is the page I was looking at, in case you were curious..

http://gcp.esub.net/cgi-bin/om_isapi...wse_Frame_Pg42

You're making me doubt it now though..

wirenut1110

Now how can you have "hicksville" north of of Mason Dixon line?

Speedy Petey

Yup, it's for real.

__________________
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.

ScottR

I knew I shouldn't have put that in my profile!

It's the stupidest name for a town (except maybe Intercourse, PA), but I grew up in the area so I just got used it...

BTW - In my defense it's not that hickish.. I've got 9 Home Depots within 10 miles of my house. (Literally 9).

wirenut1110

Guess it's better than Gofuku, Japan or Tightsqueeze, VA.

ScottR

I thought I was being gullible, so I just googled both of those. They are real. Gofuku is probably the best one ever.

wirenut1110

http://www.dribbleglass.com/Jokes/town-names.htm
Here's a whole list of them. I've lived in Va for 45 years and never heard of Tightsqueeze. May have to go visit

Gigs

There's a Bumpass, VA as well. And Butt Hollow, VA.

And also, Blacks Run, which is not too far from Lynchburg.

VA is the king of weird place names.

nap

well, it's not as good as Gofuku but we have Hell on earth in my state. (Hell Michigan)

http://www.mapquest.com/maps?city=Hell&state=MI