Multiwire Branch Circuit Question - Electrical - Page 2 - DIY Chatroom Home Improvement Forum


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

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

Reply
 
Thread Tools Display Modes
Old 06-15-2014, 04:14 PM   #16
Electrican
 
Join Date: Sep 2012
Posts: 1,135
Rewards Points: 1,614
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by Cletis View Post
MWBC's should never be used in residential as they are highly dangerous in could result in an unnecessary fatality if altered by a non electrician.

http://ecmweb.com/content/multiwire-...n-be-dangerous
Which is why the NEC now requires the breakers feeding them have handle ties.






Quote:
Originally Posted by skobydog View Post
The entire house is wired this way. I'm slowly fixing them room by room but can only do so much in the day.
There is nothing wrong with this code wise. Cletis likes to ask all the tuff questions and likes to make us think twice. Whom ever wired you home was actually doing you a favor. You can plug an iron on the top vacuum or space heater on the bottom and not worry about anything.

Only issue is if the neutral becomes open. However, as long as it doesn't this type of system will work flawlessly. Its used near 100% of the time in commercial even on much higher voltages like 277/480 and 347/600.

Advertisement

Jump-start is offline   Reply With Quote
Old 06-15-2014, 04:19 PM   #17
Electrican
 
Join Date: Sep 2012
Posts: 1,135
Rewards Points: 1,614
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by Cletis View Post
YEs, it's all dangerous, but, mwbc's should not be installed in residential because the propensity of diy's, maintainance, and HO's not knowing what they are doing can cause more than normal catastrophic effects. Until the day that only highly skilled electricians that are highly trained to work on mwbc's are allowed to do electric on residential (like myself), mwbc's should be banned until further notice...
I still remember your posts from ET...
Jump-start is offline   Reply With Quote
Old 06-15-2014, 04:29 PM   #18
Electrican
 
Join Date: Sep 2012
Posts: 1,135
Rewards Points: 1,614
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by b4bhomeowner View Post
MWBC don't play nice with *FCI breakers (required in many rooms by current NEC). One good reason not to use them in residential, aside from the experience factor.
GE took out the 30ma protection:

http://apps.geindustrial.com/publibr...ET-719|generic
Jump-start is offline   Reply With Quote
Old 06-15-2014, 04:44 PM   #19
Newbie
 
Join Date: Apr 2013
Posts: 14
Rewards Points: 10
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by Jump-start View Post
Which is why the NEC now requires the breakers feeding them have handle ties.








There is nothing wrong with this code wise. Cletis likes to ask all the tuff questions and likes to make us think twice. Whom ever wired you home was actually doing you a favor. You can plug an iron on the top vacuum or space heater on the bottom and not worry about anything.

Only issue is if the neutral becomes open. However, as long as it doesn't this type of system will work flawlessly. Its used near 100% of the time in commercial even on much higher voltages like 277/480 and 347/600.
I rewired my kitchen only because I basically gutted it. I had to move a number of outlets, added GFCIs, and numberous other things.

I'll leave the multi branch circuits in the rest of the house now that I understand them. Thanks
skobydog is offline   Reply With Quote
Old 06-15-2014, 05:22 PM   #20
Electrican
 
Join Date: Sep 2012
Posts: 1,135
Rewards Points: 1,614
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by skobydog View Post
I rewired my kitchen only because I basically gutted it. I had to move a number of outlets, added GFCIs, and numberous other things.

I'll leave the multi branch circuits in the rest of the house now that I understand them. Thanks
As long as they are on separate legs (there is 240 volts between the black and red) plus the neutral isn't disconnected while the circuit is still live you are ok. Id leave them if you are ok with them. If youd like you can actually use them yourself when adding new circuits. A piece of 14/3 or 12/3 costs less than 2 12/2s or 14/2s when you need more than 1 circuit. Very economical. You could call an electrician's secret in saving wire.


Just of note. If you are adding circuits or changing breakers in your panel they will need handle ties since code now requires both black and red to be disconnected at the same time for safety. That way you don't shut off one circuit thinking its all off only to find a live wire in a box. Home Depot and Lowes generally don't carry handle ties, however, you can use a double pole breaker instead. It is allowed by code and meets all the requirements.
Jump-start is offline   Reply With Quote
Old 06-15-2014, 05:49 PM   #21
Member
 
Join Date: Mar 2007
Location: Eighty Four, Pa.15330
Posts: 1,416
Rewards Points: 830
Default

Multiwire Branch Circuit Question


You need to get new receptacles with the jumper in place.
bobelectric is online now   Reply With Quote
Old 06-15-2014, 05:58 PM   #22
Newbie
 
Join Date: Apr 2013
Posts: 14
Rewards Points: 10
Default

Multiwire Branch Circuit Question


While I'm at it, I'm sure this has been answered before so sorry.


I see that I'm supposed to tie the breakers together and I also see under Section 210.4(D) that the cables are to be cable tied together in the panel.

What I'm not clear on installation of GFCIs. My old wiring (no GFCIs) had every receptacle split (all receptacles had the tabs broken). The tops were fed by one breaker and the bottoms by another.

Would I not do this with GFCIs?

Sorry if this is obvious. It's my first time ever working with MWBCs and every receptacle in my house is split with one breaker for the tops of the outlets and another for the bottom.

Last edited by skobydog; 06-15-2014 at 06:03 PM.
skobydog is offline   Reply With Quote
Old 06-15-2014, 06:00 PM   #23
Newbie
 
Join Date: Apr 2013
Posts: 14
Rewards Points: 10
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by bobelectric View Post
You need to get new receptacles with the jumper in place.
Yes, thanks
skobydog is offline   Reply With Quote
Old 06-15-2014, 06:24 PM   #24
Member
 
Join Date: Aug 2009
Posts: 1,262
Rewards Points: 1,638
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by skobydog View Post
While I'm at it, I'm sure this has been answered before so sorry.


I see that I'm supposed to tie the breakers together and I also see under Section 210.4(D) that the cables are to be cable tied together in the panel.

What I'm not clear on installation of GFCIs. My old wiring (no GFCIs) had every receptacle split (all receptacles had the tabs broken). The tops were fed by one breaker and the bottoms by another.

Would I not do this with GFCIs?

Sorry if this is obvious. It's my first time ever working with MWBCs and every receptacle in my house is split with one breaker for the tops of the outlets and another for the bottom.
Shouldn't have to bundle or hand tie or any of that

It's all existing.

The gfci. Pigtail the white and go to the receptacle.
Pigtail one of the circuits to the gfci.
Splice the other circuit to run through the box
ritelec is offline   Reply With Quote
Old 06-15-2014, 07:17 PM   #25
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,168
Rewards Points: 2,128
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by b4bhomeowner
MWBC don't play nice with *FCI breakers (required in many rooms by current NEC). One good reason not to use them in residential, aside from the experience factor.

Manufactures are stepping up with more available products.
stickboy1375 is offline   Reply With Quote
Old 06-15-2014, 07:35 PM   #26
FIDO...
 
Join Date: Feb 2014
Location: Minneapolis MN
Posts: 114
Rewards Points: 135
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by b4bhomeowner View Post
MWBC don't play nice with *FCI breakers (required in many rooms by current NEC). One good reason not to use them in residential, aside from the experience factor.
Over the winter, I put my kitchen's MWBC on a AFCI breaker (Eaton CH215CAF), and the two having been playing together perfectly fine.

Cheers, Chris
Chris130 is online now   Reply With Quote
Old 06-15-2014, 07:37 PM   #27
Newbie
 
Join Date: Apr 2013
Posts: 14
Rewards Points: 10
Default

Multiwire Branch Circuit Question


What I previously had was a Kitchen Split Receptacle Circuit (from what I understand).


Would this be correct for installing 6 GFCI receptacles on a multi branch circuit? All receptacles would be GFCI and all connections would be on the line side of the receptacles.

Is this correct? (Grounds are not pictured) Thanks
Attached Thumbnails
Multiwire Branch Circuit Question-untitled2.jpg  
skobydog is offline   Reply With Quote
Old 06-15-2014, 07:51 PM   #28
Member
 
Join Date: Aug 2009
Posts: 1,262
Rewards Points: 1,638
Default

Multiwire Branch Circuit Question


You got it
ritelec is offline   Reply With Quote
Old 06-15-2014, 08:12 PM   #29
Newbie
 
Join Date: Apr 2013
Posts: 14
Rewards Points: 10
Default

Multiwire Branch Circuit Question


Quote:
Originally Posted by ritelec View Post
You got it
Thanks
skobydog is offline   Reply With Quote
Old 06-15-2014, 08:15 PM   #30
Licensed electrician
 
Join Date: Sep 2007
Location: Maryland
Posts: 8,057
Rewards Points: 2,912
Default

Multiwire Branch Circuit Question


Skoby, a GFI cannot be split wired like your old setup.

Advertisement

__________________
Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.
Jim Port is online now   Reply With Quote
Reply


Thread Tools
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
SER Cable for Branch Circuit & Wire Size sdmuleman Electrical 2 04-02-2014 12:02 PM
NEC - what is the purpose of some of these codes ? chez bouton Electrical 32 12-17-2013 03:04 PM
Circuit Breaker Troubleshooting Question - need help! DanLeonard Electrical 4 10-02-2012 12:20 AM
Just for fun Andy in ATL Electrical 56 10-20-2009 10:33 AM
Wire size for dryer jamiedolan Electrical 14 01-15-2009 06:43 AM




Top of Page | View New Posts