Panels as a Raceway

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joeyww12000

joeyww12000

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Chatsworth GA
Ive asked this question before but I would like to get more info. Ive read 312.8 and I understand you can pass through a panel with other branch circuits to get to another panel, but how do you calculate the wiring space. I dont understand the math for the last half of 312.8. Thanks for the help.
 
Thats what I was thinking, but I like to know what Im saying when Im asked on the job about all of the code, not just part of it. Its been said on the last couple of jobs that you cant pass through a panel for this purpose but Ive told co-workers you can, I just wanted to be able to explain the box fill for this. Thanks.
 
joeyww12000 said:
Ive asked this question before but I would like to get more info. Ive read 312.8 and I understand you can pass through a panel with other branch circuits to get to another panel, but how do you calculate the wiring space. I don't understand the math for the last half of 312.8. Thanks for the help.
Click to expand...

Lets say the panel is 3" deep and the space between the breakers and the side of the panel is 2"

3" x 2" = 6 sq in.

312.8 allows 40% fill (or more where splices are)

6 x .4 = 2.4 sq in.

One 12 AWG THHN requires 0.0133 sq in. (Table 5 rear of NEC)

2.4 sq in / 0.0133 = 180

You could run 180 12 AWG THHNs in that 3" x 2" gutter space ............... good luck with that. :D
 
I thought that Bob's method sounded goofy, but I checked and I think he's right.

Why wouldn't it specify to determine the volume of the area, and treat it like normal box fill? :-?
 
can't resist

can't resist

peter d said:
What's wrong with my avatar? :confused:

What makes you think I'm goofy? :confused:




:D
Click to expand...


goofy.jpg.w300h418.jpg


what say you all? :grin:
 
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