Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Closed Thread
 
Thread Tools Search this Thread Display Modes
Old 12-20-2010, 01:14 PM   #1
Newbie
 
Join Date: Dec 2010
Location: Queens, NY
Posts: 3
Share |
Default

12/3 wire with ground


I was wondering. I am remodeling my kitchen and I would like to use 12/3 wire with ground to bring power to my fridge and 2 outlets at the counter top. The outlets would have its dedicated line 1 Hot(red) and the Fridge would have the other hot (black) dedicated for the fridge only. My questions is since they're 2 hot lines coming from the panel could one neutral handle it. The 2nd question is the phase. I have 2 phase coming to the house. Should I place both of the Hot line on the same Phase or If I put them on different phases would that be dangerous.

srudyv is offline  
Old 12-20-2010, 01:17 PM   #2
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Default

12/3 wire with ground


Where are you located ?

Scuba_Dave is offline  
Old 12-20-2010, 01:21 PM   #3
Newbie
 
Join Date: Dec 2010
Location: Queens, NY
Posts: 3
Default

12/3 wire with ground


New York City
srudyv is offline  
Old 12-20-2010, 01:36 PM   #4
Member
 
Join Date: Nov 2009
Location: Albany, GA
Posts: 295
Default

12/3 wire with ground


Quote:
Originally Posted by srudyv View Post
I was wondering. I am remodeling my kitchen and I would like to use 12/3 wire with ground to bring power to my fridge and 2 outlets at the counter top. The outlets would have its dedicated line 1 Hot(red) and the Fridge would have the other hot (black) dedicated for the fridge only. My questions is since they're 2 hot lines coming from the panel could one neutral handle it. The 2nd question is the phase. I have 2 phase coming to the house. Should I place both of the Hot line on the same Phase or If I put them on different phases would that be dangerous.
Local codes aside, what you are proposing is a multi-wire branch circuit (MWBC). You can share a common neutral as long as the two hot wires are connected to opposite legs with the appropriate breaker. You do have be careful in wiring a MWBC, though, as there is potential to pass 240V through a single leg of the circuit if the neutral fails. This means that all neutral connections *must* be pigtailed (you cannot pass the neutral through a receptacle from one side of the circuit to the other; if one of the receptacles fails, then whatever is plugged into the other one will probably go "boom"). Also, you need to use a double-pole 20a breaker with a tie-bar, so that if one circuit trips the breaker, both legs are cut off.

Personally, I wouldn't use a MWBC to power a fridge, since there's potential for the fridge circuit to trip off because of another appliance on the other side of the MWBC, but that's my personal preference.
clashley is offline  
Old 12-21-2010, 02:09 PM   #5
Newbie
 
Join Date: Dec 2010
Location: Queens, NY
Posts: 3
Default

12/3 wire with ground


when you mean legs do you mean phase. I was thinking to get a twin breaker that is on the same phase. Should I put it on regular single breaker on separate phase.
srudyv is offline  
Old 12-21-2010, 02:47 PM   #6
Member
 
Join Date: Nov 2009
Location: Albany, GA
Posts: 295
Default

12/3 wire with ground


Quote:
Originally Posted by srudyv View Post
when you mean legs do you mean phase. I was thinking to get a twin breaker that is on the same phase. Should I put it on regular single breaker on separate phase.
Residential service is 240V single phase. You have two hot legs coming into your service panel (the voltage between either leg and the neutral is 120V, while the voltage between the two hot legs is 240V). While these two incoming hot lines are sometimes referred to as "phases," it is incorrect.

In a multi-wire branch circuit, you *must* use a double-pole breaker with tie bar. This will tie each of the hot wires in your MWBC to opposite legs in the panel. You cannot use "skinny" or tandem breakers to power a MWBC, as these draw from a single leg. The neutral wire in 12/3 is not sized appropriately to support 40 amps of return current, which is the potential if both hot wires are connected to the same leg.

Additionally, you cannot use two single breakers to power a MWBC. If one leg of the MWBC overloads and trips, the other leg is required to trip simultaneously. This is because of the shared neutral; if only one leg trips, and the other remains hot, the neutral could still be live on both sides of the MWBC if a load exists on the untripped side of the MWBC. Using single breakers also allows for the possibility of the breakers being installed incorrectly to a single hot leg in the panel. A double-pole breaker with tie bar eliminates all of these possibilities.

MWBCs are a bit more complicated than standard 20a circuits. You must use a double-pole breaker with tie bar that will trip both legs of the circuit if either leg overloads; the double-pole breaker must draw from opposite hot legs in your service panel, and you must pigtail all neutral connections in all junction boxes (you cannot pass the neutral through receptacles),
clashley is offline  
Old 01-01-2011, 05:27 PM   #7
Member
 
Sfeyelectric's Avatar
 
Join Date: Dec 2010
Posts: 105
Default

12/3 wire with ground


Quote:
Originally Posted by srudyv View Post
I was wondering. I am remodeling my kitchen and I would like to use 12/3 wire with ground to bring power to my fridge and 2 outlets at the counter top. The outlets would have its dedicated line 1 Hot(red) and the Fridge would have the other hot (black) dedicated for the fridge only. My questions is since they're 2 hot lines coming from the panel could one neutral handle it. The 2nd question is the phase. I have 2 phase coming to the house. Should I place both of the Hot line on the same Phase or If I put them on different phases would that be dangerous.
NEC states that you need (2) 20 amp GFCI protected circuits dedicated to serve your counter tops!
Sfeyelectric is offline  
Old 01-01-2011, 05:47 PM   #8
Member
 
Join Date: Nov 2009
Location: Albany, GA
Posts: 295
Default

12/3 wire with ground


Quote:
Originally Posted by Sfeyelectric View Post
NEC states that you need (2) 20 amp GFCI protected circuits dedicated to serve your counter tops!
I don't believe the specification dictates what sort of GFCI protection is required (breaker vs. receptacle), only that the protection must be provided. For an SABC, I would prefer point-of-use protection for easier access to resets.

I believe that a MWBC would technically be permitted if point-of-use GFCI protection is provided on the SABC, although I personally wouldn't connect a refrigerator to a double-pole breaker on an MWBC (I would prefer to isolate the fridge to its own circuit to reduce the likelihood of that circuit being tripped).
clashley is offline  
Old 01-01-2011, 05:55 PM   #9
Member
 
Sfeyelectric's Avatar
 
Join Date: Dec 2010
Posts: 105
Default

12/3 wire with ground


Quote:
Originally Posted by clashley View Post
I don't believe the specification dictates what sort of GFCI protection is required (breaker vs. receptacle), only that the protection must be provided. For an SABC, I would prefer point-of-use protection for easier access to resets.

I believe that a MWBC would technically be permitted if point-of-use GFCI protection is provided on the SABC, although I personally wouldn't connect a refrigerator to a double-pole breaker on an MWBC (I would prefer to isolate the fridge to its own circuit to reduce the likelihood of that circuit being tripped).
Your 100% correct i always use the GFCI receptacles as opposed to the breaker. I was mainly making sure he understood one circuit would not be enough to cover whole counter space.

I also agree about the fridge, even when i do a job for someone i add a dedicated circuit just for the fridge. Imagine you go away for a week and something kicks that breaker now your out of the food also!
Sfeyelectric is offline  
Old 01-02-2011, 10:26 AM   #10
Scared Electrician
 
Saturday Cowboy's Avatar
 
Join Date: Nov 2009
Location: Colorado
Posts: 715
Default

12/3 wire with ground


Maybe we should ask why you want to use 12/3. It seems like a poor design decision.

NEC does require two Small Appliance Branch Circuits (SABC)to serve kitchen countertops and that they be GFI protected.

Putting an appliance and general purpose plugs on a MWBC is asking for troublesome wiring.
Saturday Cowboy is offline  
Old 01-02-2011, 01:10 PM   #11
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 13,969
Default

12/3 wire with ground


Not all Kitchens are going to need two GCFI protected circuits. I can get away with only needing one, because it is such a small Kitchen (8x10), and just went with a GCFI breaker, since it is a older home, and did not want to tear all of the Rock-lathe down for a retrofit job.
gregzoll is offline  
Old 01-02-2011, 01:18 PM   #12
Member
 
Sfeyelectric's Avatar
 
Join Date: Dec 2010
Posts: 105
Default

12/3 wire with ground


Quote:
Originally Posted by gregzoll View Post
Not all Kitchens are going to need two GCFI protected circuits. I can get away with only needing one, because it is such a small Kitchen (8x10), and just went with a GCFI breaker, since it is a older home, and did not want to tear all of the Rock-lathe down for a retrofit job.
Again According to the NEC 2008 the kitchen countertops need 2 dedicated 20amp gfci protected circuits. NEC does not state only kitchens over a certain size.

If you were to have done a complete rewire you would have had to bring it up to that standard. You however have not done so and are not required to do such!

Last edited by Sfeyelectric; 01-02-2011 at 01:34 PM.
Sfeyelectric is offline  
Old 01-02-2011, 01:22 PM   #13
Wire Chewer
 
Red Squirrel's Avatar
 
Join Date: Jun 2009
Location: Ontario, Canada
Posts: 3,211
Default

12/3 wire with ground


For separate outlets I would use two separate circuits, and not a MWBC. Where I would use a MWBC is if you have an outlet you want to make a "spit" where the top outlet is a dedicated 15 or 20 amp circuit, and the bottom is another dedicated circuit. Then you use 12/3 and a double pole breaker.

You could probably make your two outlets split if you want. Though personally for the fridge I'd run a dedicated circuit and I think that may even be code in some areas. Kitchens have very perticular codes so it's something to look into before doing any changes. Some of the codes imo don't really make sense from a safety point of view and can make things harder, but still have to follow them.
Red Squirrel is offline  
Old 01-02-2011, 01:47 PM   #14
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 13,969
Default

12/3 wire with ground


My Kitchen has 3. Not all kitchens are going to have two counter cicuits, especially if they are small kitchens. I would only have one outlet if I had left it as is, but in my case, three outlets was the magic number. I know what the NEC states, but pointing out the obvious, not all Kitchens warrant two GFCI protected circuits. That does nothing to state how many outlets, it is circuits (ie more than one breaker).
gregzoll is offline  
Old 01-02-2011, 01:57 PM   #15
Member
 
Sfeyelectric's Avatar
 
Join Date: Dec 2010
Posts: 105
Default

12/3 wire with ground


Quote:
Originally Posted by gregzoll View Post
My Kitchen has 3. Not all kitchens are going to have two counter cicuits, especially if they are small kitchens. I would only have one outlet if I had left it as is, but in my case, three outlets was the magic number. I know what the NEC states, but pointing out the obvious, not all Kitchens warrant two GFCI protected circuits. That does nothing to state how many outlets, it is circuits (ie more than one breaker).
Well if it is being done to code as it should be. It must have 2 circuits serving the kitchen counter tops. We are here to encourage DIY's to do things in a professional and legal way, Thus we should only make recommendations as the code reads.

Sfeyelectric is offline  
Closed Thread

Tags
elecrrical line, electic warming, electical


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
What wire gauge for plumbing ground? bob22 Electrical 4 04-04-2010 07:01 PM
This doesnt seem right. JoulesWinfield Electrical 27 07-26-2009 07:40 PM
hooking up dryer....bronx ny code SURFBUG Appliances 6 10-14-2008 09:41 PM
Ground rod or not? brotherman Electrical 30 07-15-2008 04:58 PM
Sub panel grounding sluggermike Electrical 27 11-11-2007 01:23 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.