Box fill calculation

[Provision]

So a contractor I do work for sent a pic and asked if there’s anything wrong. Besides the obvious I told him those pancake boxes only allow for 6 cu in and having a 12/2 romex adds up to 6.75 cu in. I was called on this once during an inspection. The electrician on the job is saying grounds don’t count unless they are isolated. From what I’ve researched the ground does count, if there are multiple grounds they all only count as one wire but still you’re supposed to add in 2.25 cu in for it. Does anyone know the truth? Im unable to dl the photo for some reason..

 

[packersparky]

So a contractor I do work for sent a pic and asked if there’s anything wrong. Besides the obvious I told him those pancake boxes only allow for 6 cu in and having a 12/2 romex adds up to 6.75 cu in. I was called on this once during an inspection. The electrician on the job is saying grounds don’t count unless they are isolated. From what I’ve researched the ground does count, if there are multiple grounds they all only count as one wire but still you’re supposed to add in 2.25 cu in for it. Does anyone know the truth? Im unable to dl the photo for some reason..

The EGC does count as one conductor.

From 314.16(B)(5)

(5) Equipment Grounding Conductor Fill. Where one or
more equipment grounding conductors or equipment bonding
jumpers enter a box, a single volume allowance in accordance
with Table 314.16(B) shall be made based on the largest equipment
grounding conductor or equipment bonding jumper
present in the box.

 

[infinity]

So a contractor I do work for sent a pic and asked if there’s anything wrong. Besides the obvious I told him those pancake boxes only allow for 6 cu in and having a 12/2 romex adds up to 6.75 cu in. I was called on this once during an inspection. The electrician on the job is saying grounds don’t count unless they are isolated. From what I’ve researched the ground does count, if there are multiple grounds they all only count as one wire but still you’re supposed to add in 2.25 cu in for it. Does anyone know the truth? Im unable to dl the photo for some reason..

What does that have to do with box fill?

Yes they count, for a pancake box we use either 2 wire AC or MC-ap cable where the jacket is the EGC.

 

[Dennis Alwon]

I have heard this before about a pancake box and the equipment grounding conductor. I wonder why one thinks it would count everywhere else and not in the pancake box.

 

[jeff48356]

On a side note, I always thought the box fill allowance in pancake boxes is actually higher, because those are used for installing bathroom vanity lights where the center of the sink happens to be right over a stud. Then the electrician has no choice but to install a pancake box, or the homeowner/GC will complain about the lights being off-center. My understanding is that if a fixture is installed, then the space under the base of the fixture adds to the box capacity.

 

[Dennis Alwon]

On a side note, I always thought the box fill allowance in pancake boxes is actually higher, because those are used for installing bathroom vanity lights where the center of the sink happens to be right over a stud. Then the electrician has no choice but to install a pancake box, or the homeowner/GC will complain about the lights being off-center. My understanding is that if a fixture is installed, then the space under the base of the fixture adds to the box capacity.

The canopy does add if the canopy is marked,. I haven't seen any that were marked

 

[jeff48356]

The canopy does add if the canopy is marked,. I haven't seen any that were marked

Then I guess the best bet, whenever I run into such a situation, is to ask the GC if he could move the stud over a few inches. Then I would be able to install a regular box.

 

[Dennis Alwon]

You can use a fan box. This goes up one side of the 2xXX and has plenty of room

 

[LarryFine]

Or use a hole saw to cut a circular cut-out in the 2x4, break out the wood "slug" with Channel-locks, and use a deeper round/octagonal box.