Multiple Circuits In One Box? - Electrical - 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 07-22-2009, 02:57 PM   #1
Newbie
 
Join Date: Jul 2009
Posts: 4
Rewards Points: 10
Default

Multiple circuits in one box?


I'm getting ready to wire an office and have a question regarding circuits. Initially, I was going to run a single 20A circuit for 5 two-outlet receptacles (same ones you find on all the walls in your house). When I got to looking at the specs for the equipment I'm going to put in there, I realized my copier can draw a max of 1090W when copying! Since at the 80% rule I shouldn't stuff more than 1920W on a circuit, that doesn't leave much room for the other stuff going there. So, I was thinking about running its own 20A circuit, but what I'd like to do is run that circuit to one or two of the existing boxes and then have the top outlets be on the original circuit and the bottom outlets be on the new circuit. I'd label the covers so it was obvious which was which. I know I'll have to cut the tabs on the receptacles. Is there anything else that would be wrong with this? Is there anything in the code against running two cables next to each other through the same holes in the studs? Any problems with having two many cables in the boxes?

Thanks for your help.

Advertisement

jdc1040 is offline   Reply With Quote
Old 07-22-2009, 04:55 PM   #2
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,964
Rewards Points: 2,324
Default

Multiple circuits in one box?


You must use a 2 pole breaker for this set up!

Advertisement

__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is online now   Reply With Quote
Old 07-22-2009, 05:07 PM   #3
Newbie
 
Join Date: Jul 2009
Posts: 4
Rewards Points: 10
Default

Multiple circuits in one box?


Even if not using a common neutral? I'm talking about running two entirely separate 12/2 cables.
jdc1040 is offline   Reply With Quote
Old 07-22-2009, 05:16 PM   #4
RST
DIY Homeowner
 
Join Date: Jul 2009
Location: Indiana
Posts: 169
Rewards Points: 150
Default

Multiple circuits in one box?


If you're going to go to the trouble of running another 12/2 cable, why not run a 12/3 cable with a double pole breaker?

But thinking about your suggestion.... you will probably have to upsize the boxes. There are limits to how many current conducting wires you can have in a box (others can clarify this further).

Maybe you could have a dedicated circuit for the copier? You probably thought of that already, but figured I throw it out there...

Robert
RST is offline   Reply With Quote
Old 07-22-2009, 05:50 PM   #5
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,964
Rewards Points: 2,324
Default

Multiple circuits in one box?


Quote:
Originally Posted by jdc1040 View Post
Even if not using a common neutral? I'm talking about running two entirely separate 12/2 cables.
Yes! Because the yolk of the device will have two distinct circuits, even not sharing a neutral.
I would save some trouble and run a 12/3, but it still must be on a double pole breaker.
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is online now   Reply With Quote
Old 07-22-2009, 05:53 PM   #6
Newbie
 
Join Date: Jul 2009
Posts: 4
Rewards Points: 10
Default

Multiple circuits in one box?


I had thought of running 12/3 with a double-pole breaker, but then I read some articles talking about how it's easy to screw up to where you could create a shorting situation where the wire heats up and starts a fire. I figured it's easier to just stick with what I know how to do (regular old circuits) and not tempt fate. I may still go with a single run just for the copier though.
jdc1040 is offline   Reply With Quote
Old 07-22-2009, 06:04 PM   #7
zpm
yeah, right
 
Join Date: Jan 2009
Location: California
Posts: 142
Rewards Points: 75
Default

Multiple circuits in one box?


There's also the issue of having to use AFCIs, if you are required to and/or care. Are two pole AFCI's even available yet at a reasonable price? Better off to have a 2 gang box and use a duplex recep for each circuit.
__________________
Honey, does this tool belt make me look FAT?
zpm is offline   Reply With Quote
Old 07-22-2009, 06:05 PM   #8
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Rewards Points: 2,000
Default

Multiple circuits in one box?


Quote:
Originally Posted by jdc1040 View Post
I'm I realized my copier can draw a max of 1090W when copying! Since at the 80% rule I shouldn't stuff more than 1920W on a circuit, that doesn't leave much room for the other stuff going there. So, I was thinking about running its own 20A circuit, but what I'd like to do is run that circuit to one or two of the existing boxes and then have the top outlets be on the original circuit and the bottom outlets be on the new circuit. I'd label the covers so it was obvious which was which. I know I'll have to cut the tabs on the receptacles. Is there anything else that would be wrong with this? Is there anything in the code against running two cables next to each other through the same holes in the studs? Any problems with having two many cables in the boxes?

Thanks for your help.
You only need to worry about the 80% rule if you are going to be running continous loads = say 3-4 hours

As Jbfan said: run a 20a 240v breaker (required) with 12-3
There is no problem with running 20a 240v dual circuit run
This automatically puts the loads across opposite "phases" - neutral will not overheat

The problem used to be when single circuit breakers were used & placed on the same "phase"
Instead of the load blancing out across the neutral the load would ADD across the neutral
That's a simple explanation, but basically what happens

I run multiple 20a 240v dual circuits for my Chriustmas display at 90%+ without any problems


You can run 2 cables thru the same hole in a stud
Boxes are rated to hold a certain wmount of wires
How many depends upon th ebox size
If it s a blue plastic box the numbers are stamped on the inside of the box
Scuba_Dave is offline   Reply With Quote
Old 07-23-2009, 11:00 AM   #9
Newbie
 
Join Date: Jul 2009
Posts: 4
Rewards Points: 10
Default

Multiple circuits in one box?


Thanks for the help! The best options seem to be either running a separate circuit just for the copier or doing 12/3 with a 2 pole breaker as suggested. Won't need AFCI since code only requires it in bedrooms here. The bottom line will probably be how "portable" I want the copier to be in the room. If there's really only one spot I want to put it in, I'll just run it's own circuit. If I might want to move it across the room at some point, I'll probably go with the split receptacles. Thanks again for the help!

Advertisement

jdc1040 is offline   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
Multiple Circuits needs The Layman Electrical 27 05-20-2010 01:00 PM
Power on several circuits comes and goes all at once, never trips breaker Michael H Electrical 22 06-29-2009 09:22 AM
replacing old wire on existing circuits... red86yota Electrical 9 12-08-2008 07:00 PM
Multiple Circuits - Same Outlet box Revnjeff Electrical 2 09-04-2008 09:17 PM
One neutral for two circuits?? TronCarter Electrical 13 01-14-2007 09:21 AM




Top of Page | View New Posts