DIY Home Improvement Forum banner

Box fill - Reliable calculators?

2K views 3 replies 3 participants last post by  fuzzball03 
#1 · (Edited)
The various exceptions and writing of the NEC have me a bit tripped up on this.

Are there any ONLINE box fill calculator that someone cant point me to that are reliable/accurate?

The numbers I'm getting dont seem to match anything.


I have a 3 gang box with:
2 x 12/2 (4 x 2.25)
3 x 14/2 (6 x 2.00)
3 devices - 2 conductors each, so is it (6 x 2.25) or (4 x 2.25 + 2 x 2.00)?
internal clamps (2.25)
Largest ground (2.25)

So I've got: 9 + 12 + 13.5 + 2 + 2.25 = 39.00

http://www.constructionmonkey.com/calculations/electrical/boxfill.aspx
Gives me 32.30

Where am I going wrong?
 
See less See more
#3 · (Edited)
It's not you. The calculator is only counting the devices as a single conductor.

I have a 3 gang box with:
2 x 12/2 (4 x 2.25)
3 x 14/2 (6 x 2.00)
3 devices - 2 conductors each (4 x 2.25 + 2 x 2.00) largest conductor connected to the device.
internal clamps (2.25)
Largest ground (2.25)

Should read: 9 + 12 + 13 + 2.25 + 2.25 = 38.5
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top