3 circuits in one 2 gang box

[treyp3]

Is there a rule, and if so where, that says I cant have 3 circuits in one box? I want to hang a 2 gang nail on box in a kitchen. I want to use it for switch and receptacle. I want to use a 14-3 conductor (two pole 15 amp breaker) home run for dish and disposal, and a 12-2 kitchen appliance circuit. So I will have a 3 wire feeding a switch leg for the disposal and a hot for the dish washer. Also, I'd have a 12-2 wire for the kitch. app.The wire fill is 29.75 cu. in. and the box is 32 cu. in. I've been told this isn't legal, but I don't know where to look it up.

 

[Dennis Alwon]

As long as the fill is met then there is no issue with having 3 circuits in a 2 gang box. BTW I get 29.75 also.

 

[infinity]

Take a look at 314.16.

 

[dhalleron]

This rule implies you can have more than two circuits in a box:

NEC 2011
210.7 Multiple Branch Circuits. Where two or more
branch circuits supply devices or equipment on the same
yoke, a means to simultaneously disconnect the ungrounded
conductors supplying those devices shall be provided
at the point at which the branch circuits originate.

 

[copper chopper]

what am i doing wrong.

what am i doing wrong.

its been a decade since i had to do this, but i cant figure out how you guys are getting your answer, this is what i am doing.

14/3 from panel--3 #14 x 2.00 = 6
14/2 to dishwasher--2 #14 x 2.00 = 4
14/2 to disposal--2 #14 x 2.00 = 4
1 switch--2 #14 = 4
12/2 to outlet--2 #12 x 2.25 = 4.50
all grounds= 2.25 per (314.16-5)
gfi outlet--2.25 #12 = 4.50 per (314.16-4)


Total = 29.25 box fill

am I missing or forgetting something???

 

[GoldDigger]

This rule implies you can have more than two circuits in a box:

NEC 2011
210.7 Multiple Branch Circuits. Where two or more
branch circuits supply devices or equipment on the same
yoke, a means to simultaneously disconnect the ungrounded
conductors supplying those devices shall be provided
at the point at which the branch circuits originate.

Actually, it limits what you can have on one yoke. So a two-gang box could have four circuits.

In the OP's case, the SABC receptacle(s) would be on one yoke, the switch for the garbage disposal would be on the other, and the pre-wire to the dishwasher would not connect to either yoke, so it could be on a third dedicated circuit if desired.

It looks to me as if the primary application of that rule is for an MWBC wired to a split receptacle so that one side of the MWBC supplies each of the two receptacles.
It could also deal with the safety problem of a yoke with a switch on one branch circuit and an outlet on the other, or two switches on different branches. The hazard in the first case is that someone might think that the yoke was touch-safe for removal when only the receptacle circuit was de-energized.

The conservative approach would be to de-energize all circuits passing through the box, but that may be hard to verify without removing one or more yokes to get your non-contact tester near the wires at the back of the box.

 

[Dennis Alwon]

The switch and outlet counts as 2 wires rated 2.25 not just 2. Thus you have 2.25 x 4= 9 cu,in for the devices alone

 

[Volta]

Here's what I get, same as copper:
14/3 - 3 #14 x 2.00 = 6 cu in
14/2 - 2 #14 x 2.00 = 4
14/2 - 2 #14 x 2.00 = 4
switch - 2 #14 x 2.00 = 4
12/2 - 2 #12 x 2.25 = 4.5
EGC - x #12 x 2.25 = 2.25
outlet - 2 #12 x 2.25 = 4.5

Total cu in required = 29.25

 

[Dennis Alwon]

Here's what I get, same as copper:
14/3 - 3 #14 x 2.00 = 6 cu in
14/2 - 2 #14 x 2.00 = 4
14/2 - 2 #14 x 2.00 = 4
switch - 2 #14 x 2.00 = 4
12/2 - 2 #12 x 2.25 = 4.5
EGC - x #12 x 2.25 = 2.25
outlet - 2 #12 x 2.25 = 4.5

Total cu in required = 29.25

Yes but copper edited his post after my reply

 

[infinity]

Yes but copper edited his post after my reply

:happysad:

There is no limit as long as the box fill isn't exceeded. How many different circuits do you think are in here? :jawdrop:

 

[iwire]

How many different circuits do you think are in here? :jawdrop:

All of them.

 

[GoldDigger]

:happysad:

There is no limit as long as the box fill isn't exceeded. How many different circuits do you think are in here? :jawdrop:

I am more curious what the jumper cables in the upper right corner are doing. :blink:

 

[iwire]

I am more curious what the jumper cables in the upper right corner are doing. :blink:

I was wondering who was welding on the can but than I realized my scale was off, that is a clip on lead from a meter.

 

[infinity]

I was wondering who was welding on the can but than I realized my scale was off, that is a clip on lead from a meter.

Yes, I had to trouble shoot a few circuits in there. hmy:

 

[curt swartz]

I always wonder why so many electricians take the 14/3 DW/Disp home run to the switch box first then drop down to the receptacle. I have always run the home run to the receptacle then run a dead end switch loop to the switch. Much easier to make up and reduces the wire fill at the switch box.

 

[ActionDave]

I always wonder why so many electricians take the 14/3 DW/Disp home run to the switch box first then drop down to the receptacle. I have always run the home run to the receptacle then run a dead end switch loop to the switch. Much easier to make up and reduces the wire fill at the switch box.

I don't know why they did it then. It has to be done now in case you want to put a dimmer on your garbage grinder.

 

[GoldDigger]

I don't know why they did it then. It has to be done now in case you want to put a dimmer on your garbage grinder.

More likely a presence sensor. (I cringe at the thought....)

But you can still do it in that order and just run 14/3 for your switch leg. Leaves more room in the box for the dimmer.

 

[ActionDave]

More likely a presence sensor. (I cringe at the thought....)

That would be a fun way to freak my wife out. "Every time I walk by the sink the disposer turns on."

"Really. I never noticed that. Are you sure?"

 

[logan92@att.net]

I'm surprised no mentioned that you cannot exceed 600 volts in the box either. Just saying!! Of cours youd have to have 5 120 v ckts to come close.
:huh:

 

[kwired]

I don't know why they did it then. It has to be done now in case you want to put a dimmer on your garbage grinder.

That rule wouldn't apply here, it only applies to switches for lighting outlets. Even the lighting outlets have some exceptions - like if the lighting outlet doesn't use a grounded conductor. (Did not look, but pretty certain this is correct)

I'm surprised no mentioned that you cannot exceed 600 volts in the box either. Just saying!! Of cours youd have to have 5 120 v ckts to come close.
:huh:

Doesn't work that way. If you have a 30 circuit breaker panel with 30 120 volt circuits installed, your logic says there would be 3600 volts in there. If it is a 120/240 volt system, you will not find any two points that have more than 240 volts between them.