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

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

Reply
 
Thread Tools Search this Thread Display Modes
Old 12-29-2008, 06:06 PM   #1
Newbie
 
Join Date: Dec 2008
Location: Plymouth, Michigan
Posts: 13
Share |
Default

Using 14-3 wire for two 15A circuits


I am currently adding circuits to my basement and noticed that the original wiring of the sump pump and furnace is done using a common 14-3 wire instead of individual 14-2 wires. The 14-3 wire runs from the service panel to a junction box where 14-2 wires then feed the sump pump outlet and the furnace. Is this common practice? The only benefit I can see in doing this is that only one wire has to be run the majority of the distance, about 40 feet in my case. It still uses the same amount of circuit breakers as running individual wires. The electrician has also used this technique for the dishwasher and the garbage disposal.

david.plymouth is offline   Reply With Quote
Old 12-29-2008, 06:34 PM   #2
My License Ain't 4 Sale..
 
Join Date: Feb 2008
Location: Atlanta, Ga/Hamilton, Al
Posts: 1,813
Default

Using 14-3 wire for two 15A circuits


Quote:
Originally Posted by david.plymouth View Post
I am currently adding circuits to my basement and noticed that the original wiring of the sump pump and furnace is done using a common 14-3 wire instead of individual 14-2 wires. The 14-3 wire runs from the service panel to a junction box where 14-2 wires then feed the sump pump outlet and the furnace. Is this common practice? The only benefit I can see in doing this is that only one wire has to be run the majority of the distance, about 40 feet in my case. It still uses the same amount of circuit breakers as running individual wires. The electrician has also used this technique for the dishwasher and the garbage disposal.
I wouldn't say that it is very common, but it is legal. It is called a multiwire branch circuit. The only rub is that the two hot conductors must be on different phases of the panel, otherwise the neutral could be overloaded. In areas following the 2008 code, the two hots must be on a double pole breaker. Also, make sure the breaker(s) that feed your equipment are 15 A, and no higher.

InPhase277 is offline   Reply With Quote
Old 12-29-2008, 07:38 PM   #3
Member
 
joed's Avatar
 
Join Date: Mar 2005
Location: Welland, Ontario
Posts: 7,459
Default

Using 14-3 wire for two 15A circuits


I don't know how common it is but I would do it that way. One 14/3 is cheaper than two 14/2 cables.
It's legal. Any electrician would know what is right away. It might confuse an inexperienced home owner, but that is not really a concern.
joed is offline   Reply With Quote
Old 12-29-2008, 08:08 PM   #4
Member
 
Join Date: Oct 2007
Posts: 2,294
Default

Using 14-3 wire for two 15A circuits


It's called a multi wire branch circuit and here it is very common. I avoid it just to avoid the potential issues related to it. It's hard not to use it with the DW/disposal and kit counter top circuit because it is going to the same box in many cases.

The 2 hot wires must be on seperate phases/legs and your neutral connections had better be bulletproof. If you lose the neutral path back to the panel you may end up with 240V at your 120V circuits.

THey also must be on a 2 pole breaker as of 2008 code.
220/221 is offline   Reply With Quote
Old 12-30-2008, 09:46 AM   #5
When is fishing season?
 
CowboyAndy's Avatar
 
Join Date: Feb 2008
Posts: 613
Default

Using 14-3 wire for two 15A circuits


MWBC's are pretty common around here. They can save on materials and labor.
__________________
I DON'T OWN MY HOUSE...
MY HOUSE OWNS ME!
CowboyAndy is offline   Reply With Quote
Old 12-30-2008, 10:10 AM   #6
Member
 
Join Date: Dec 2008
Posts: 31
Default

Using 14-3 wire for two 15A circuits


Instead of pulling 14/3, I would pull 12/3 to be safe. The difference in price is minor...
duckdown is offline   Reply With Quote
Old 12-30-2008, 10:16 AM   #7
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,743
Default

Using 14-3 wire for two 15A circuits


Quote:
Originally Posted by duckdown View Post
Instead of pulling 14/3, I would pull 12/3 to be safe. The difference in price is minor...
Why would you be safer?
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is offline   Reply With Quote
Old 12-30-2008, 10:21 AM   #8
DIYer
 
Join Date: Oct 2008
Location: Virginia
Posts: 910
Default

Using 14-3 wire for two 15A circuits


I think he means safer from having to do it over if your ampacity needs grow.
Gigs is offline   Reply With Quote
Old 12-30-2008, 10:47 AM   #9
Res Ipsa Loquitur
 
Join Date: Dec 2007
Location: Southeastern PA
Posts: 363
Default

Using 14-3 wire for two 15A circuits


Quote:
Originally Posted by duckdown View Post
Instead of pulling 14/3, I would pull 12/3 to be safe. The difference in price is minor...
If it is already installed and connecting a permanent item like furnace and sump, I wouldn't change it. I would consider upgrading if it supplied receptacles which could be used heavily at times.
__________________
Did you ever stop to think, then forget to start again?
handyman78 is offline   Reply With Quote
Old 12-30-2008, 11:43 AM   #10
Newbie
 
Join Date: Dec 2008
Location: Plymouth, Michigan
Posts: 13
Default

Using 14-3 wire for two 15A circuits


I'm installing a whirlpool bath in the basement which requires two separate 15 amp circuits, one for the pump and one for the heater. Is it okay to use a 12-3 wire for these two circuits or should I go with separate 14-2 circuits (or 12-2)?
david.plymouth is offline   Reply With Quote
Old 12-30-2008, 02:21 PM   #11
Member
 
joed's Avatar
 
Join Date: Mar 2005
Location: Welland, Ontario
Posts: 7,459
Default

Using 14-3 wire for two 15A circuits


It only needs 14/3 for 15 amp circuits. I would NOT use two 14/2s or two 12/2.
joed is offline   Reply With Quote
Old 12-30-2008, 02:59 PM   #12
elect, contractor
 
Join Date: Nov 2008
Location: niagara ontario
Posts: 44
Default

Using 14-3 wire for two 15A circuits


absolutly nothing wrong with it proding it is circuited aproapriatly in the panel, customers allways want the lowest price, so whereever time and materials can be saved legally most of us end up doing it. I personaly would not go to the extent of a seperate junction box to split it, nor will I use a connection to a device as a splitting point for the neutral, it is seperatly marreted and tagged, and make note on the panel of the spliting point, and that it is a mwbc.
ACB Electric is offline   Reply With Quote
Old 12-30-2008, 03:10 PM   #13
Newbie
 
Join Date: Dec 2008
Posts: 16
Default

Using 14-3 wire for two 15A circuits


I saw this for the first time in a home I was working on yesterday. Almost one whole side of 100amp sub panel was wired this way. Kinda freaked me out for a second but figured it out quick and its good to know now that its legal. Thanks guys!
cambruzzi is offline   Reply With Quote
Old 12-30-2008, 03:21 PM   #14
Member
 
Join Date: Dec 2007
Location: Baltimore, MD
Posts: 1,802
Default

Using 14-3 wire for two 15A circuits


Quote:
Originally Posted by cambruzzi View Post
I saw this for the first time in a home I was working on yesterday. Almost one whole side of 100amp sub panel was wired this way. Kinda freaked me out for a second but figured it out quick and its good to know now that its legal. Thanks guys!
What were you doing in the panel?
jerryh3 is offline   Reply With Quote
Old 12-30-2008, 03:23 PM   #15
Member
 
Join Date: Jul 2008
Location: Pennsylvania, USA
Posts: 272
Default

Using 14-3 wire for two 15A circuits


Whirlpool baths, a.k.a. "hydromassage tubs" in the 2008 NEC, require GFCI protection, and that GFCI must be readily accessible.

So, you have a choice of GFCI receptacles under the tub that must be readily accessible, or GFCI breakers at your panel.

(680.71 NEC)

__________________
Willis
williswires is offline   Reply With Quote
Reply


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
replacing old wire on existing circuits... red86yota Electrical 9 12-08-2008 06:00 PM
hooking up dryer....bronx ny code SURFBUG Appliances 6 10-14-2008 09:41 PM
Dryer Grounding??? Traci_howdyadothat Electrical 7 05-27-2008 01:14 PM
Installing Fluorescents in Garage rzrbkpk Electrical 26 04-08-2008 09:00 PM
Stranded wire on screw connections BigJimmy Electrical 7 01-19-2008 02:42 PM




Top of Page | View New Posts

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