Box Fill Question - Electrical - DIY Chatroom Home Improvement Forum

 DIY Chatroom Home Improvement Forum Box Fill Question
 Register Blogs Articles Rewards Search Today's Posts Mark Forums Read

03-06-2008, 03:21 AM   #1
Member

Join Date: Aug 2007
Posts: 179
Rewards Points: 150

Box Fill Question

I am using the blue plastic carlon outlet boxes 18 cu in. Do I have this right.
On the box as far as fill, it says 9-14 8-12 7-10. If I am using 12/2. I have 2 blacks plus a pigtail = 3 , 2 white's plus a pigtail = 3 , 2 grounds plus a pigtail = 1 , and one outlet=2. So that's 9 > 9x2.25 =20.25. So the 18 cu in. box is no good. Now what about the wire nuts do they get factored in. Thanks

03-06-2008, 06:45 AM   #2
When is fishing season?

Join Date: Feb 2008
Posts: 613
Rewards Points: 500

Yes, for 14AWG is 9, 12AWG is 8 and 10AWG is 7.

Pigtails I am not sure about, Hopefully someone can clarify 314.16 (B)(1) where it stated "A conductor, no part of which leaves the box, shall not be counted". Would this encompass a pigtail?

__________________
I DON'T OWN MY HOUSE...
MY HOUSE OWNS ME!

03-06-2008, 06:55 AM   #3
You talking to me?

Join Date: Dec 2007
Location: sw mi
Posts: 7,551
Rewards Points: 6,290

Quote:
 Originally Posted by CowboyAndy Yes, for 14AWG is 9, 12AWG is 8 and 10AWG is 7. Pigtails I am not sure about, Hopefully someone can clarify 314.16 (B)(1) where it stated "A conductor, no part of which leaves the box, shall not be counted". Would this encompass a pigtail?
Correct.

the only part I am not clear on concerning this wire count is;

you have only 2 cables entering the box, correct? and simply put, you are making joints in those cables, correct?

If so, your count is good other than the pigtails (not counted).

so, it should be 7 X 2.25=15.75. You are good to go.

03-06-2008, 07:17 AM   #4
When is fishing season?

Join Date: Feb 2008
Posts: 613
Rewards Points: 500

Quote:
 Originally Posted by nap Correct. so, it should be 7 X 2.25=15.75. You are good to go.

7? Shouldn't it be 6?
__________________
I DON'T OWN MY HOUSE...
MY HOUSE OWNS ME!

 03-06-2008, 07:46 AM #5 Electrical Contractor   Join Date: Feb 2008 Location: Colonia, NJ Posts: 127 Rewards Points: 75 All grounds count as one conductor. Clamps count as one conductor (in this case, plastic box no clamp no count) The device that you put in the box (receptical, switch) counts as two wires.
 03-06-2008, 07:56 AM #6 When is fishing season?     Join Date: Feb 2008 Posts: 613 Rewards Points: 500 Got it. Thanks. __________________ I DON'T OWN MY HOUSE...MY HOUSE OWNS ME!
 03-06-2008, 08:04 AM #7 Electrical Contractor   Join Date: Feb 2008 Location: Colonia, NJ Posts: 127 Rewards Points: 75 Just to make it clear You have two 12-2 cables coming into a plastic box with a max of 8 wires allowed in the box. The blacks count as 2 The whites count as 2 Grounds count as 1 The receptacle counts as 2 For a total of 7 wires in the box. You only count wires entering and leaving the box. Pigtails don't figure into the count.
 03-06-2008, 08:07 AM #8 When is fishing season?     Join Date: Feb 2008 Posts: 613 Rewards Points: 500 So essentially, with an 18CI box, you can only have 2 cables coming into it (because of counting the device)? What is the next size up box? __________________ I DON'T OWN MY HOUSE...MY HOUSE OWNS ME!
 03-06-2008, 08:22 AM #9 Res Ipsa Loquitur   Join Date: Dec 2007 Location: Southeastern PA Posts: 363 Rewards Points: 250 Carlon single-gang blue new-work boxes come 18, 20, 22 cu in. __________________ Did you ever stop to think, then forget to start again?
 03-06-2008, 08:48 AM #10 When is fishing season?     Join Date: Feb 2008 Posts: 613 Rewards Points: 500 I don't think I have ever actually looked at them. Then again, I have never had to run more than 2 caables in or out of a box. __________________ I DON'T OWN MY HOUSE...MY HOUSE OWNS ME!
 03-06-2008, 09:16 AM #11 electrician   Join Date: Feb 2008 Posts: 326 Rewards Points: 250 Something else to be aware of. If you use the Carlon "Super Blue" boxes that plastic clamp for the romex instead of the cheaper ones that you knock that little square piece of plastic out of, you have to deduct 1 for the integral clamps inside the box. The cubic inch capacity is based on the UL ratings, but you will have to deduct from the stamped cubic inch capacity for proper fill to be compliant with 314.16(B)(2). I don't believe an inspector would ever call you on it though.
 03-06-2008, 09:36 AM #12 Member   Join Date: Aug 2007 Posts: 179 Rewards Points: 150 Cool, Thanks for the info. Next time I will go with the 20 or 24's just to be safe for future expansion.
 03-06-2008, 09:57 AM #13 Res Ipsa Loquitur   Join Date: Dec 2007 Location: Southeastern PA Posts: 363 Rewards Points: 250 Here is a link to Carlon products catalog- http://www.carlon.com/Master%20Catal...0Boxes_2B1.pdf the Super Blue Single gang are 22 cu in. They probably try to compensate for the integral clamps with 2 cu over the standard blue boxes. If you need more space you can also go with a double gang box and use a single opening mudring. In Lowes I have seen a single gang box with an extra side bumpout for additional space. __________________ Did you ever stop to think, then forget to start again? Last edited by handyman78; 03-06-2008 at 10:05 AM.
03-07-2008, 12:19 AM   #14
Member

Join Date: Aug 2007
Posts: 179
Rewards Points: 150

Quote:
 Originally Posted by handyman78 Here is a link to Carlon products catalog- http://www.carlon.com/Master%20Catal...0Boxes_2B1.pdf the Super Blue Single gang are 22 cu in. They probably try to compensate for the integral clamps with 2 cu over the standard blue boxes. If you need more space you can also go with a double gang box and use a single opening mudring. In Lowes I have seen a single gang box with an extra side bumpout for additional space.
Good Idea I actually have a case of single opening mud rings from a past BX job.

03-13-2008, 10:35 AM   #15
Member

Join Date: Aug 2007
Posts: 179
Rewards Points: 150

Not to beat a dead horse but, I have a 4 gang box with 3 sets of 12/3 and 4 sets of 12/2. Box is 60 cu in. It will take 26- 12 ga. wires, says box. My count is 25 with wire and switches, Not including grounds. Are all these grounds considered one. This should be the last question from me about box fill. lol Thanks
Attached Thumbnails

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post KUIPORNG Remodeling 234 08-26-2008 09:19 AM memovox2 HVAC 4 02-01-2008 11:05 AM Onytay Electrical 1 10-24-2007 06:47 AM lh0628 HVAC 4 10-11-2007 11:17 PM

Top of Page | View New Posts