DIY Home Improvement Forum banner

Adding additional outlet. Pigtail four sets of wires?

10K views 5 replies 3 participants last post by  kbsparky 
#1 ·
I'm adding an additional electrical outlet to the backside of a wall which has the existing outlet I want to tap into. The new outlet will be directly behind the existing outlet. The current outlet has three sets of romex wires coming into the box, so I'm assuming that the 3rd set is going to a wall light switch.

Is it safe to tap into this outlet and pigtail four sets of wires? All of the wires are connected to the outlet rather than being pigtailed. Two sets of wires are using the backstab holes and one set is using the screws on the side. There is still a set of screws on the other side, but I'm thinking it would be easier (and safer) to pigtail the four sets of wires with a 6" lead going to the outlet. The bare ground wires are already pigtailed using a couple metal crimps, which I would replace with a wire nut.
 
#2 ·
What is the size of the box in cubic inches?
What gauge are the wires?

I'm guessing you either must have rather shallow boxes or 2x6 walls if you can fit an outlet box directly behind the one in the other room. To fit 4 wires (11 "conductors" - +4 hots, +4 neutrals, +1 grounds, +2 outlet) that are #14, you will need a box with a minimum volume of 20.25 cubic inches. For #12, 24.75 cubic inches.

http://ecmweb.com/nec/electric_box_fill_calculations/
 
#3 ·
Thanks for the info. You're right about placing the new box directly behind the existing one. No way it would fit, so I will place it near the next stud.

Current box is single gang, 18" cu. in. Wires are all 14 guage. Looks like I'll just upgrade to a double gang box.

My biggest concern was pig tailing four sets of wires, and if this was a big no-no. Thanks for your help.
 
#5 ·
I just assumed the existing box was 18 cu in, but after double-checking I found that it is indeed 23 cu in. Glad I checked again, since it seems that old work 23" boxes are hard to find at the local stores. Also trying to remove the current box without damaging the drywall seems like it would be a real pain.

Thanks again for the help.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top