20amp 2pole on 12/3 wire

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Joe the Rugg

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A contractor in a single family dwelling is installing 20amp 2pole breakers on 12/3 wire. He put the 2 appliance ckts on one , the dishwasher and disposal on another 20 amp 2pole. The last 20amp 2pole he put the refrig. and wire nutted off the last hot as a spare. I don't think this is a good practice but I can't find anything in the NEC that says he can't do it. please help.
 
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stew

Senior Member
Location
federal way,washington
Re: 20amp 2pole on 12/3 wire

This is a very common practice using 12/3 with a shared neutral. as a matter of fact when you do use the shared neutral you are required in resi to have handle ties or a simutaneous means to break both circuits which the 2 pole does as weell.
 
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redfish

Senior Member
Re: 20amp 2pole on 12/3 wire

I don't think this is a good practice but I can't find anything in the NEC that says he can't do it. please help.
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210.4 Multiwire Branch Circuits </font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">(A) General Branch circuits recognized by this article shall be permitted as multiwire circuits. A multiwire circuit shall be permitted to be considered as multiple circuits. All conductors shall originate from the same panelboard or similar distribution equipment.</font>
<font size="2" face="Verdana, Helvetica, sans-serif"></font>
  • <font size="2" face="Verdana, Helvetica, sans-serif">(B) Devices or Equipment Where a multiwire branch circuit supplies more than one device or equipment on the same yoke, a means shall be provided to disconnect simultaneously all ungrounded conductors supplying those devices or equipment at the point where the branch circuit originates.</font>
<font size="2" face="Verdana, Helvetica, sans-serif">I hope this helps, it is out of the 2005 CODE
 
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sheldon_ace

Member
Location
Owego, NY
Re: 20amp 2pole on 12/3 wire

Originally posted by stew:
This is a very common practice using 12/3 with a shared neutral. as a matter of fact when you do use the shared neutral you are required in resi to have handle ties or a simutaneous means to break both circuits which the 2 pole does as weell.
Click to expand...
you only need a handle tie or common trip 2 pole when the multiwire bc feeds two devices on the same yolk. since the circuits are feeding different equipment, no common trip is needed.
 
electricmanscott

electricmanscott

Senior Member
Location
Boston, MA
Re: 20amp 2pole on 12/3 wire

You can take that spare and feed 1/2 of a 20 amp duplex behind the fridge and then you can plug in your portable cord and plug connected under cabinet light without violating 210.52 (B) (3).
smiley_butt.gif


[ September 02, 2005, 09:50 PM: Message edited by: electricmanscott ]
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Re: 20amp 2pole on 12/3 wire

Originally posted by electricmanscott:
You can take that spare and feed 1/2 of a 20 amp duplex behind the fridge and then you can plug in your portable cord and plug connected under cabinet light without violating 210.52 (B) (3).
Click to expand...
But then aren't you required to use a 20-amp duplex, since each half of said receptacle is now a single receptacle, as specified in 210.21(B)(1)?
 
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jimwalker

Senior Member
Location
TAMPA FLORIDA
Re: 20amp 2pole on 12/3 wire

A trick i learned years ago is run that attic light on a dedicated 20 amp circuit.Should a circuit ever be needed for what ever reason you have the wire in a very friendly place.

As to spare tires ,i went crazy one morning trying to figure out how to get it out from under my exsplorer.Took about half hour to figure it out in the dark :mad: :mad:
 
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allenwayne

Senior Member
Re: 20amp 2pole on 12/3 wire

Ok the 2 S.A. circuits (2 pole 20 )
disp. / D.W. (if same yoke gets a handle tie or standard 2 pole)
What about the dinning / nook are they fed at all
sounds like the SPARE was for those,or maybe some ran a dinning / nook circuit and when found out a wire nut was easier to leave than chamge out ;)
 
electricmanscott

electricmanscott

Senior Member
Location
Boston, MA
Re: 20amp 2pole on 12/3 wire

Originally posted by LarryFine:
Originally posted by electricmanscott:
You can take that spare and feed 1/2 of a 20 amp duplex behind the fridge and then you can plug in your portable cord and plug connected under cabinet light without violating 210.52 (B) (3).
Click to expand...
But then aren't you required to use a 20-amp duplex, since each half of said receptacle is now a single receptacle, as specified in 210.21(B)(1)?
Click to expand...
I'll just assume you were sleepy when you posted this. :D
 
J

Joe the Rugg

Member
Re: 20amp 2pole on 12/3 wire

Yoke in the electrical handbook is described as that little break off tab on a receptacle. My background is in commerical, where one neutral for 3 hots but we don't put them on a 3pole breaker. If it is common practice in resi let me know and I won't have problem because it does seem just as safe.
joe the rugg
 
roger

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Re: 20amp 2pole on 12/3 wire

Joe, I think you're confussing the break off jumper/device connector with the mounting yoke.

receptacle_yoke.jpg


Using the 2005 NEC, if you land more than one leg or phase on a single yoke, you must must provide a handle tie or use a multi-pole breaker, see 210.4(B)


Roger

[ September 04, 2005, 08:56 AM: Message edited by: roger ]
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: 20amp 2pole on 12/3 wire

Originally posted by Joe the Rugg:
Yoke in the electrical handbook is described as that little break off tab on a receptacle.
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What handbook says that?

I have never heard that and believe that is incorrect.

In dwelling units, a multiwire branch circuit supplying more than one device or equipment on the same yoke shall be provided with a means to disconnect simultaneously all ungrounded conductors at the panelboard where the branch circuit originated.

This could be a two pole breaker, a listed handle tie across two single pole breakers or IMO even a two pole switch at the panel board.

My background is in commerical, where one neutral for 3 hots but we don't put them on a 3pole breaker.
Click to expand...
There are times even in commercial that handle ties are required for multiwire branch circuits.

210.4(B) (2005 NEC) this is a change from 2002 it now applies to all occupancies.

Also check out 210.7 (2002 or 2005 NEC) for multiple circuits feeding a single yoke or strap

Multiwire circuits feeding office cubicles are now required to have handle ties. 605.6 or 605.7 2005 NEC.
 
roger

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Re: 20amp 2pole on 12/3 wire

Bob, I wasn't as detailed in my post as you were though. :)

Roger
 
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