nail on knock out

[jetlag]

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.

 

[TOOL_5150]

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

~matt

 

[jetlag]

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]

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]

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

 

[Sierrasparky]

Who makes these new boxes you speak of?

 

[walkerj]

Who makes these new boxes you speak of?

Southwire.

 

[jetlag]

Who makes these new boxes you speak of?

I dont have a box with me but will check tommorrow, if I can figure how will attach photo

 

[LarryFine]

The NEC says more than one cable in a box KO is okay. Read the last sentence of the 314.17(C) exception.

 

[jaylectricity]

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

I strip the wires before they ever enter the box.

 

[jxofaltrds]

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]

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?

 

[jetlag]

How does .8 cu in help us?

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

 

[jetlag]

You don't strip the wire before you put it in the box?

no the code requires a precise strip thats hard to hit that way . i use long hawk bill knife that will reach in to exact spot . u f cable i do strip first .

 

[jxofaltrds]

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]

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

 

[jaylectricity]

no the code requires a precise strip thats hard to hit that way

Which code is that?

 

[jxofaltrds]

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.

 

[jetlag]

(3) 14-2 = 12
(1) 12-2 = 4.5
EGC = 2.25
And no device

Thank you for the math lesson.

your welcome , since it has no device I dont mind full box fill , with device I dont like to fill to max

 

[jetlag]

thanks larry

thanks larry

The NEC says more than one cable in a box KO is okay. Read the last sentence of the 314.17(C) exception.

Thats good I dont remember reading the exception. Exhibit 3.14.5 in the 2008 hand book shows a single gang nail on with 2 12-2 nm in same K O