# Multi – Multi wire branch circuits



## raider1 (Jan 22, 2007)

You won't find a specific code section that prohibits what you described.

But, 2008 NEC section 210.4(B) requires a means to simultaneously disconnect all ungrounded conductors of a multiwire branch circuit. It could be rather tough to find a 6 pole breaker or an identified handle tie for 6 single pole breakers.

Chris


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## Gravy (Feb 19, 2009)

Interesting way of looking at it - I hadn't thought of it that way.

I 'spose sharing a neutral would make all of the ungrounded conductors part of the same MWBC. :wacko:

Good on ya!! If you're a drinker and we ever cross paths the first round is on me :thumbsup:


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## brian john (Mar 11, 2007)

Local terminology? - FULL BOAT = ?


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## brian john (Mar 11, 2007)

raider1 said:


> You won't find a specific code section that prohibits what you described.
> 
> But, 2008 NEC section 210.4(B) requires a means to simultaneously disconnect all ungrounded conductors of a multiwire branch circuit. It could be rather tough to find a 6 pole breaker or an identified handle tie for 6 single pole breakers.
> 
> Chris


Long 1/8" toggle bolt will do the trick on some CBs.:no:


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## Speedy Petey (Jan 10, 2007)

Unless you ran #8 neutrals to EVERYTHING tap rules would also come into play. No?


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## brian john (Mar 11, 2007)

Speedy Petey said:


> Unless you ran #8 neutrals to EVERYTHING tap rules would also come into play. No?


I would not do as the OP is suggesting (in the past or now), but not sure where you are heading with your post?


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## NolaTigaBait (Oct 19, 2008)

brian john said:


> Long 1/8" toggle bolt will do the trick on some CBs.:no:


I was thinkin about a long nail:laughing:


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## Bob Badger (Apr 19, 2009)

Gravy said:


> I am looking for the specific code that prohibits a single oversized grounded (neutral) conductor when you are installing multiple full boats.
> 
> For example a 3 phase panel 120/208 with two (20 amp/ckt.) full boats (six ungrounded conductors) what prohibits me from running a single #8 awg grounded conductor as opposed to two #12’s?
> 
> I have talked with a couple of guys here at work and the best we can come up with is that it is simply bad practice but I would like to be able to cite a specific code it violates. I’m still looking into this so if I find something before I get any responses I will post them here. Thanks for your help.


Actually NEC specifically allows that for outdoor circuits.

I do have to ask how you think that would work out money wise by the time you deal with bigger boxes and wire connectors.


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## raider1 (Jan 22, 2007)

brian john said:


> Local terminology? - FULL BOAT = ?


Yeah, "Full Boat" is a local slang term for a multiwire branch circuit that is run in a raceway. 

Usually in my area a full boat is A,B & C phase with a neutral and an EGC of the wire type where specified.

Chris


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## raider1 (Jan 22, 2007)

Gravy said:


> Interesting way of looking at it - I hadn't thought of it that way.
> 
> I 'spose sharing a neutral would make all of the ungrounded conductors part of the same MWBC. :wacko:
> 
> Good on ya!! If you're a drinker and we ever cross paths the first round is on me :thumbsup:


Next time I'm in Minnesota I will look you up.:thumbsup:

Chris


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## william1978 (Sep 21, 2008)

brian john said:


> Local terminology? - FULL BOAT = ?


 I never heard it called that till a few weeks ago and the guy that used that term said it was B,R,Bl,W or B,O,Y,G.


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## brian john (Mar 11, 2007)

raider1 said:


> Yeah, "Full Boat" is a local slang term for a multiwire branch circuit that is run in a raceway.
> 
> Usually in my area a full boat is A,B & C phase with a neutral and an EGC of the wire type where specified.
> 
> Chris


Well I learned something today, so waking up was not a waste.

We call it a multi-wire branch circuit.


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## knowshorts (Jan 9, 2009)

"Full boat" is used in SoCal also. I forgot what I used to call it.


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## MDShunk (Jan 7, 2007)

I've heard full boat as referring to any 5-wire circuit.


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## 480sparky (Sep 20, 2007)

Full boat to me means three hots and a noodle on a three-phase system. Ground is whatever you're using for ground.... conductor or pipe.


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## Adam12 (May 28, 2008)

480sparky said:


> Full boat to me means three hots and a noodle on a three-phase system. Ground is whatever you're using for ground.... conductor or pipe.


We commonly use the term "full boat" around here too. Meaning what 480 described.


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## eddy current (Feb 28, 2009)

Round here we use the term "full set" to describe one conductor of each phase and a neutral.


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## DERITM (Apr 8, 2009)

"Networks" in Chicagoland.


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## RePhase277 (Feb 5, 2008)

We call them "full sets" or "networks" as well. I never heard the term full boat until I read it on some electrical forums.


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## robnj772 (Jan 15, 2008)

Around here a "Full boat" means there are more guys on the boat then fishing rods..... :laughing:


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## qckrun (May 18, 2009)

We call them full boats, round robin's In california. Never in california have I heard it referred to actually term, MWBC.


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## McClary’s Electrical (Feb 21, 2009)

william1978 said:


> I never heard it called that till a few weeks ago and the guy that used that term said it was B,R,Bl,W or B,O,Y,G.


 

Neither one of these examples are full boats, the first one could be,, if ran in metal pipe for EGC,,,,but the second cannot be used as described


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## RePhase277 (Feb 5, 2008)

mcclary's electrical said:


> Neither one of these examples are full boats, the first one could be,, if ran in metal pipe for EGC,,,,but the second cannot be used as described


I think the G means gray, not green, so it would still be a full set.


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## leland (Dec 28, 2007)

*Regional-*

Full boat- not used here either- But I've learned a lot of terms here.


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## ampman (Apr 2, 2009)

brian john said:


> Local terminology? - FULL BOAT = ?


 thats a new one to me -- but i like it


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## JayH (Nov 13, 2009)

Full boat made me think of this image sent to me by an owner's rep on a school project I did a couple of years ago...


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## rdr (Oct 25, 2009)

Always heard a full boat. 

Never knew MWBC other than code book and forums. Never heard anybody use the term day to day.


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## Gravy (Feb 19, 2009)

Bob Badger said:


> Actually NEC specifically allows that for outdoor circuits.
> 
> I do have to ask how you think that would work out money wise by the time you deal with bigger boxes and wire connectors.


I re-read my post and don't see where I gave the impression I thought this was a good idea?

Full boat, as described, is all three phase conductors with a shared neutral. The term can be used for either 208/120 or 480/277 (maybe others but these are most common). It's a common term here - not sure about other places.

Glad I could teach some of you a little slang:jester:

Anyone wanna know what a blue a**hole is?:001_huh:























































:laughing:


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## SparkYZ (Jan 20, 2010)

We'll call it a full boat which will have 3 hots and a neutral. I'll say with or without ground. "120 colors" or "480 colors" determines whether its B,R,BL or B, O, Y


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## Ray Cyr (Nov 21, 2007)

Gravy said:


> I am looking for the specific code that prohibits a single oversized grounded (neutral) conductor when you are installing multiple full boats.
> 
> For example a 3 phase panel 120/208 with two (20 amp/ckt.) full boats (six ungrounded conductors) what prohibits me from running a single #8 awg grounded conductor as opposed to two #12’s?
> 
> I have talked with a couple of guys here at work and the best we can come up with is that it is simply bad practice but I would like to be able to cite a specific code it violates. I’m still looking into this so if I find something before I get any responses I will post them here. Thanks for your help.


This wouldn't fit the Art. 100 definition of a MWBC. The 2 wires on phase "A" wouldn't have a voltage between them etc.


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