Two circuits in 2-gang box?


  #1  
Old 01-26-18, 10:31 AM
B
Member
Thread Starter
Join Date: Oct 2001
Location: USA
Posts: 976
Received 9 Upvotes on 9 Posts
Two circuits in 2-gang box?

I'm planning a kitchen remodel for my brother. Can I put two receptacles in a two gang box and have two separate circuits in that 2-gang box?
 
  #2  
Old 01-26-18, 10:53 AM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 4,807
Upvotes: 0
Received 0 Upvotes on 0 Posts
So you want each receptacle on it's own circuit?
This is pretty common for dishwashers and garbage disposer wiring.

You normally feed the two receptacles using a multi-wire branch circuit. You would run 12-3/with ground to a 20 amp double pole breaker in the panel. The double pole breaker assures both circuits will trip at the same time.

The neutral is shared by using 2 pigtails, one for each receptacle. The black wire would feed one receptacle hot and red would feed the other.

If you use a mwbc, do not use the receptacle screws to extend the neutral to the second receptacle. Connect 2 pigtails to the incoming shared neutral and connect one pigtail to each receptacle. That is required when splitting the circuit.
 
  #3  
Old 01-26-18, 11:03 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 9,871
Received 185 Upvotes on 166 Posts
The double pole breaker assures both circuits will trip at the same time.

Common trip of both circuits in a multiwire branch circuit is not required by the NEC, only common disconnect of the two circuits is required. That is why the preferred method is to use an approved handle tie across two adjacent single pole breakers for the multiwire branch circuit rather than using a 2-pole breaker. When using a handle tie troubleshooting a problem that has tripped one breaker is much easier. If a 2-pole breaker was used additional troubleshooting is needed to determine which circuit has the fault.


Can I put two receptacles in a two gang box and have two separate circuits in that 2-gang box?

Yes. Connect all ground wires together, but DO NOT connect the neutrals together unless this is a multiwre branch circuit with a shared neutral.
 
  #4  
Old 01-26-18, 11:06 AM
B
Member
Thread Starter
Join Date: Oct 2001
Location: USA
Posts: 976
Received 9 Upvotes on 9 Posts
Thanks! The 20A double pole breaker makes sense; never occurred to me. My brother suggested it and I was visualizing someone killing power to one receptacle and reaching into the box thinking everything was dead!!
 
  #5  
Old 01-26-18, 11:17 AM
B
Member
Thread Starter
Join Date: Oct 2001
Location: USA
Posts: 976
Received 9 Upvotes on 9 Posts
"Yes. Connect all ground wires together, but DO NOT connect the neutrals together unless this is a multiwre branch circuit with a shared neutral."

OK, you lost me a bit on that; sorry, I'm not all that familiar with electrical beyond the basics. Are you saying I can't use a 12/3 and have a common neutral? I should run two 12/2's with the handle tie across two adjacent breakers? Simple trouble shooting sounds smart to me.
 
  #6  
Old 01-26-18, 01:08 PM
L
Member
Join Date: Nov 2015
Posts: 1,573
Received 201 Upvotes on 172 Posts
I can't use a 12/3 and have a common neutral? I should run two 12/2's with the handle tie across two adjacent breakers?
If you wire it as MWBC (multi wire branch circuit), use 12/3 with shared neutral. And either 2 pole breaker or 2 single pole breakers with a handle tie.

You may also run 2 12/2 cables. In this case, do not connect neutrals together in the junction box. All ground wires get spliced.
In this case, handle tie is not required. But, don't forget that you have to turn off 2 breakers to cut all power to the junction box. Any electrician should be smart enough to see that when they open the box.
 

Last edited by pcboss; 01-26-18 at 02:39 PM.
  #7  
Old 01-26-18, 01:15 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 4,807
Upvotes: 0
Received 0 Upvotes on 0 Posts
In this case, handle tie is not required. But, don't forget that you have to turn off 2 breakers to cut all power to the junction box.
If you decide to run two individual breakers, I would use a Sharpie marker and print on the inside of the cover plate "this box is served by two circuits" or something to that effect.
 
  #8  
Old 01-27-18, 03:08 AM
B
Member
Thread Starter
Join Date: Oct 2001
Location: USA
Posts: 976
Received 9 Upvotes on 9 Posts
Thanks all for being patient with me. Still not sure which way I'll finally go, but at least I understand what I can do. But I do know for sure if I go with 2 separate breakers and 12/2's, the breakers will have a handle tie. The possibility of having one dead and one hot circuit in the same box just doesn't sound safe to me.
 
  #9  
Old 01-27-18, 08:33 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,332
Received 877 Upvotes on 740 Posts
As electricians we install many circuits in the same junction box. As long as all wires are insulated and caped off it is OK.
 
  #10  
Old 01-29-18, 05:32 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,523
Upvotes: 0
Received 278 Upvotes on 254 Posts
What was said earlier was that each neutral must serve only the items (receptacles, etc.) served by the matching hot wire. For a multiwire branch circuit, the neutral serves both the red wire and black hot wire in the same cable and multiple pigtails (jumpers) may be attached to that neutral to go to receptacles served by either of those hot wires.

For the separate 12/2 cables you will have two wire nutted bundles of neutrals with no interconnection, one for each cable's neutral and pigtails (or a neutral connected directly to a receptacle also receiving the black wire from that feed cable with no wire nuts or pigtails).
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: