box fill including grounds

[adobecontracting]

I have a inspector who is counting every ground as a single conductor, which means in a 18cu.in.single device box with 3 #12/wg romex, 9 wires are already overfill, isn't all grounds counted as one? If not when did that change? I've always been of the understanding; device as 1, grounds as 1 and conductors are counted individualy next. the box should have 8 total by this calcuation.

 

[Guest]

Re: box fill including grounds

Look at 314.16

 

[don_resqcapt19]

Re: box fill including grounds

Have your inspector look at 314.16(B)(5).
Don

edited to correct typo

[ October 16, 2003, 02:49 PM: Message edited by: don_resqcapt19 ]

 

[drg]

Re: box fill including grounds

The device will be counted as 2 #12 conductors and yes, the grounds together will count as 1 #12 conductor .

If I understand you have three 12-2 NM-B cables and one device in your box, if so your calculations will be 20.25 Cu.In. for your total box fill assuming you are using a plastic box without a internal clamp.

John

 

[ryan_618]

Re: box fill including grounds

Originally posted by drg:
The device will be counted as 2 #12 conductors and yes, the grounds together will count as 1 #12 conductor .

If I understand you have three 12-2 NM-B cables and one device in your box, if so your calculations will be 20.25 Cu.In. for your total box fill assuming you are using a plastic box without a internal clamp.

John

You got it!

 

[websparky]

Re: box fill including grounds

Here is what I get:

Three #12 NM entering box = 7 volumes @ 2.25" = 15.75".

Add two volumes for a single device = 4.50".

Add both - 15.75" + 4.50" = 20.25" total fill.

Resulting in overfill for a box rated at 18".