nail on knock out

Status
Not open for further replies.

jetlag

Senior Member
I noticed the newer single gang 18.8 nail ons have quite large knock out I usually just put 1 #12 each knock out, is there any code you cant put two. But on the double gang with clamp I assume they intend for one cable each clamp.
 

jetlag

Senior Member
thanks tool

thanks tool

In the knock outs, you can put 2 cables in, if it has clamps, you can only put 1 cable per clamp.

~matt
Boy thats odd only 1 reply , I was getting worried people only put one in knock out so they didnt really know if could use 2 . I didnt want to have to pull some out. It just seemed to me be better to use 2 #12 than have the big gapping hole when 1 conductor is used in k o . The k o were not as big on the blue boxes , these are the black ones big blue is stocking now , you also get .8 more cu in over the blue 18 cu in.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
Generally I will use one cable per hole but I have used 2 cables per hole in a pinch. I believe some of them are rated for 2 cables just as some connectors will allow 2 cables.
 

jetlag

Senior Member
thanks dennis

thanks dennis

Generally I will use one cable per hole but I have used 2 cables per hole in a pinch. I believe some of them are rated for 2 cables just as some connectors will allow 2 cables.
I prob should pull them out, it is just roughed right now, because I dont know where to check the box rating , its only a few boxes, anyway the wires are easier to strip if not on top of each other in same k o
 

jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
Boy thats odd only 1 reply , I was getting worried people only put one in knock out so they didnt really know if could use 2 . I didnt want to have to pull some out. It just seemed to me be better to use 2 #12 than have the big gapping hole when 1 conductor is used in k o . The k o were not as big on the blue boxes , these are the black ones big blue is stocking now , you also get .8 more cu in over the blue 18 cu in.
How does .8 cu in help us?
 

Hendrix

Senior Member
Location
New England
I prob should pull them out, it is just roughed right now, because I dont know where to check the box rating , its only a few boxes, anyway the wires are easier to strip if not on top of each other in same k o
You don't strip the wire before you put it in the box?
 

jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
This sounds like an electricity 101 quiz question

1 extra space beyond an allowed box fill makes a device easier to install
2 if a box only lacks .8 to install another cable, adding .8 to box allows it
3 the more box space the merry

ans : all of the above :)
How does #2 apply?

(3) 14-2 + device = 18.0 cu in

(2) 14-3 + device = 18.0 cu in

12-2 + 12-3 + device = 18.0 cu in

How does .8 cu in help?
 

jetlag

Senior Member
How does #2 apply?

(3) 14-2 + device = 18.0 cu in

(2) 14-3 + device = 18.0 cu in

12-2 + 12-3 + device = 18.0 cu in

How does .8 cu in help?
On a 15 amp branch circuit a nail on box with a blank cover is used for a junction box and contains 3 # 14-2 nm cables and 1 #12-2 UF cable . To help prevent voltage drop the 12-2 uf was used to run to a remote storage building. Find the minimum cu in required for the nail on box.

(correct answer 18.75 cu in ) Darn I can use that 18.8 box for something :)
 

jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
On a 15 amp branch circuit a nail on box with a blank cover is used for a junction box and contains 3 # 14-2 nm cables and 1 #12-2 UF cable . To help prevent voltage drop the 12-2 uf was used to run to a remote storage building. Find the minimum cu in required for the nail on box.

(correct answer 18.75 cu in ) Darn I can use that 18.8 box for something :)
(3) 14-2 = 12
(1) 12-2 = 4.5
EGC = 2.25
And no device

Thank you for the math lesson.
 
Status
Not open for further replies.
Top