EGC count in the Jbox

[electrofelon]

Safety issue when over time the conductors insulation is displaced because they were forced into place when the device screws are tightened and a short circuit or ground fault results.

I don't understand the above.

 

[don_resqcapt19]

I don't understand the above.

The insulation is thermoplastic. It displaces over time when subjected to pressure. It can displace enough to result in the metal part that the conductor is pressing against contacting bare conductor.

 

[electrofelon]

The insulation is thermoplastic. It displaces over time when subjected to pressure. It can displace enough to result in the metal part that the conductor is pressing against contacting bare conductor.

It is certainly best practice to carefully fold in the conductors as the device is installed. Seen plenty crammed in and wires bent tightly even with NEC box fill

 

[don_resqcapt19]

It is certainly best practice to carefully fold in the conductors as the device is installed. Seen plenty crammed in and wires bent tightly even with NEC box fill

Not required by the code, so the only thing that helps is the maximum permitted box fill.

 

[electrofelon]

Not required by the code, so the only thing that helps is the maximum permitted box fill.

I don't see it helping, that is my point.

 

[letgomywago]

The whole thing has never made sense to me. The volume of the conductor does not change based on the function of the conductor. Why aren't all EGCs counted individually like grounded and ungrounded conductors?

I think we should count wirenut types more than even just splices. We should have volume counts on all this stuff if we wanted more than napkin calcs. I've put gfis and smart switches in smaller boxes like an 18cu that with wirenuts wouldn't fit nice but splicing at the device clamps fits ok. But we don't need it crazy either just funny they bothered since it's the most common violation type.

 

[AC\DC]

IMO the entire box fill thing should just be deleted. For one thing, in 25 years, I don't recall an inspector even once looking at and calculating my box full. Second it just seems like a design issue. Any reasonable electrician isn't going to want to fight with a overstuffed box where you have to fight to get the device in and/or take half an hour being as neat as possible to save space . The rule might have some value to a brother in law, but the NEC should be a how to book for DIY's.

hey man I getting close to my bid number I going to fill that as much as I can if its getting to my pocket book. My wife does say I am unreasonable

 

[Ponchik]

OK. so my OP, how would you calculate it?

 

[WD40]

Kinda crazy that 100 years ago we had smaller boxes and fatter wires, now we have bigger boxes and thinner wires.

Houses built 100 years ago here were 'knob and tube' or BX cable where all the splices were soldered and rubber taped in the wall, never in a box so all you had in a outlet box was the leads to that outlet.
And there was not bare ground wire then.
So those box fill requirements may not have changed much but the way we wire changed.

 

[Dsg319]

I just think it is a pointless rule in practice. There are just too many variables: device size, neatness of makeup, length of conductors. I remember I installed one of those four gang size radio RA things a while back. Took me about an hour to to make up the box absolutely as neatly and as tight as possible to get that thing to fit in there.

Exactly. I just wish I could go about my days splicing in form 7 conduit fittings (which have plenty of room) without giving people coronary spasms.

Idk how many times I’ve technically been over full on a splice in a form7 Tee and still been neat and never had an issue getting the cover on.

 

[electrofelon]

Houses built 100 years ago here were 'knob and tube' or BX cable where all the splices were soldered and rubber taped in the wall, never in a box so all you had in a outlet box was the leads to that outlet.
And there was not bare ground wire then.
So those box fill requirements may not have changed much but the way we wire changed.

When they first started using ramen or BX, they would fill those boxes up! Particularly light boxes it seems.