Need Info on Wiring Outlets

Reply

  #1  
Old 05-14-16, 04:03 PM
Member
Thread Starter
Join Date: May 2016
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Need Info on Wiring Outlets

I'm hooking up a few circuits and outlets in my shop. I'm using MWBC to cut down on the wiring and have a few questions concerning wiring the outlets. I'm using THHN stranded wire and outlets with the screw clamps for stranded. Is there a special way outlets have to be wired if using MWBC? If so, what is it? If not and they are wired like any standard outlet, is it ok to connect all connections directly to the clamps with the screws (kinda like in a series, though its not) or should I use pigtails? If you use pigtails, when determining gang box size would you have to include 3 splices in the box and 3 terminations in addition to the wires that just run through the box to other circuits?
 
Sponsored Links
  #2  
Old 05-14-16, 04:05 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,219
Received 478 Votes on 448 Posts
You haven't disclosed how you are using a MWBC but what you should do is bring the circuit to the shop and then separate it into two distinct circuits.

Name:  MWBCD.jpg
Views: 833
Size:  18.2 KB
 
  #3  
Old 05-14-16, 04:07 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 13,022
Received 68 Votes on 60 Posts
With a MWBC you are required to splice the neutral and use pigtails. You cannot rely on the device for the neutral connection. The hots may be wired anyway you want, but I would also recommend using pigtails.

Pigtails do not count towards box fill.
 
  #4  
Old 05-14-16, 04:09 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,983
Received 35 Votes on 30 Posts
Don't forget the shop requires gfi protection for the 120 volt 15 and 20 amp receptacles.
 
  #5  
Old 05-14-16, 07:45 PM
Member
Join Date: Mar 2010
Location: USA
Posts: 3,686
Received 30 Votes on 29 Posts
When feeding ground fault circuit interrupter receptacles using a multiwire branch circuit you must do one of:
1. Put a GFI receptacle unit with load terminals empty at each outlet box, or,
2. At the first outlet box separate the MWBC into two distinct subcircuits.

Or you can do (3) use a GFI breaker back at the panel and use just regular receptacles in the shop.
 
  #6  
Old 05-15-16, 11:27 AM
Member
Thread Starter
Join Date: May 2016
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
Ok, thanks everyone. But I need clarification on two points. Tolyn said pigtails don't count for box fill. Does that also mean you don't count the splice that's on one end of the pigtail and the termination to the outlet on the other end. I will have 2 hot wires, 1 neutral and 1 ground passing through a double/2 gang box. I will pigtail off ONE of those hots and off the neutral and ground to connect the 2 outlets in that gang box. That will require a total of 6 pigtails in each box. What would be my total count for splices per box, terminations per box and wires passing through? Also in figuring box count, do all conductors count or just the CCC. Hope I haven't over complicated this question but when told pigtails didn't count I had me wondering if the pigtail splices and terminations did since it's only the pigtail that's terminated and/or spliced.
 
  #7  
Old 05-15-16, 11:46 AM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,593
Received 6 Votes on 6 Posts
Box Fill

Box fill is determined by the number of conductors entering and leaving the box. Plus other things such as device, clamps, etc. Pigtails inside the box have no bearing on box fill.
 
  #8  
Old 05-15-16, 02:07 PM
Member
Thread Starter
Join Date: May 2016
Location: USA
Posts: 10
Received 0 Votes on 0 Posts
I found a box fill calculator but it asks for number and size of conductors passing through, number and wire size of terminations and wire size and number of splices in a box. It then computes how many square inches of box you need. Is that irrelevant since you are saying splices and terminations don't matter? I'm confused???
 
  #9  
Old 05-15-16, 03:16 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 13,022
Received 68 Votes on 60 Posts
Wires that do not enter or leave the box are not counted.
Splices do not count to box fill

Name:  box fill.jpg
Views: 573
Size:  23.4 KB
Image source: Box Fill Calculations

Here is an easy way to calculate box fill:
Count the wires entering the box not counting grounds (1 per each wire)
Count the wires leaving the box not counting grounds (1 per each wire)
Count all internal clamps (1 per all internal clamps)
Count the devices (switches/receptacles) (2 per each device)
Count all the grounds as one wire (1 per all the grounds)

Each #14 = 2 Cu In
Each #12 = 2.25 Cu In
 
Reply

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


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