410.20

[Fifer]

What is the practical application of NFPA70E 410.20? It states:

"Canopies and outlet boxes taken together shall provide sufficient space so that luminaire conductors and their connecting devices are capable of being installed in accordance with 314.16"

So, what exactly is this saying that 314.16 isn't? 314.16(A) already establishes that you can use a fixture as a box fill extention if it has a marked volume, so what is 410.20 saying that this isn't already?

 

[tortuga]

My guess is to take into account a fixture canopy can have other optional stuff in it, a ceiling fan remote control unit comes to mind.
Up until recently (2008) not all light fixtures (and retrofit kits) were required to be listed, meaning the code permitted one to be assembled by electricians out of parts, so 410 contained allot of 'construction specifications' related to building your own fixture (luminaire).

 

[Rick 0920]

If you used a 4" round by 1/2" deep listed fan box, a 14-3 would overfill the box in a calculation. It's saying that you can use a canopy as additional space even though the canopy does not have a marked volume.

 

[Fifer]

If you used a 4" round by 1/2" deep listed fan box, a 14-3 would overfill the box in a calculation. It's saying that you can use a canopy as additional space even though the canopy does not have a marked volume.

So what you're saying is that 410.20 just completely overrides 314.16(A)? How much additional space do I get? What are the restrictions?

 

[tortuga]

So what you're saying is that 410.20 just completely overrides 314.16(A)? How much additional space do I get? What are the restrictions?

Since it still ties in article 314 you just need to have enough space for the wires, if a fixture canopy and is not marked your permitted to do a quick eyeball calc and decide if its sufficient.

 

[Fifer]

Since it still ties in article 314 you just need to have enough space for the wires, if a fixture canopy and is not marked your permitted to do a quick eyeball calc and decide if its sufficient.

Ha! Give me one other section of the code that even remotely allows you to just eyeball things. That's not a thing and never has been in our book. C'mon man, you're just making things up at this point.

 

[cadpoint]

How many canopy lights have you seen or they gave the marked volume? I never have.
Even with all of 110.3 (Charlie moment) - where one is supposed to read directions.

Opening remarks of 110.3(A) opens up the can of worms. @Fifer

My opinion you can't use the canopy, volume wise, your only to use the 6" of wire from the box.
Yes I know - no one stuffs the 6" back inside the box and use the canopy...

 

[don_resqcapt19]

My take is that as long as the box has enough volume for the branch circuit conductors in the box, you can use the canopy for the volume required for the luminaire conductors.

 

[Fifer]

How many canopy lights have you seen or they gave the marked volume? I never have.
Even with all of 110.3 (Charlie moment) - where one is supposed to read directions.

Opening remarks of 110.3(A) opens up the can of worms. @Fifer

My opinion you can't use the canopy, volume wise, your only to use the 6" of wire from the box.
Yes I know - no one stuffs the 6" back inside the box and use the canopy...

My thoughts exactly. My reading is that, unless the canopy is marked, which I have yet to run across one that is, just keep following your normal box fill calculation.

 

[Fifer]

My take is that as long as the box has enough volume for the branch circuit conductors in the box, you can use the canopy for the volume required for the luminaire conductors.

Same here. In fact I saw a Mike Holt video, you know the ones where him and a couple other dudes are sitting at a long table taking questions from the audience, where he runs a question about if the wire clamps inside our pancake boxes can push you over the limit. He runs out the calculation, specifically mentioning that you don't count the luminaire conductors cause the canopy takes care of them, but he doesn't cite the article to back up that statement... and then proceeds with the rest of the calculation.

By the way, rip those wire clamps out if you have them. Unless you can get a marked volume canopy to comply with 314.16(A), 14/2 and 12/2 both run the calculation right up to the edge of the available space. Internal wire clamps push you over, no matter what.

 

[Rick 0920]

Same here. In fact I saw a Mike Holt video, you know the ones where him and a couple other dudes are sitting at a long table taking questions from the audience, where he runs a question about if the wire clamps inside our pancake boxes can push you over the limit. He runs out the calculation, specifically mentioning that you don't count the luminaire conductors cause the canopy takes care of them, but he doesn't cite the article to back up that statement... and then proceeds with the rest of the calculation.

By the way, rip those wire clamps out if you have them. Unless you can get a marked volume canopy to comply with 314.16(A), 14/2 and 12/2 both run the calculation right up to the edge of the available space. Internal wire clamps push you over, no matter what.

The article and section that backs up the statement is Art. 314.16 (B)(1) Ex.

 

[tortuga]

Ha! Give me one other section of the code that even remotely allows you to just eyeball things.

410.20 modifies 314.16 saying all you need is 'sufficient space', not a marked cubic inches, that's just my opinion.
You need to prove sufficient space to the AHJ, and yeah a inspector might want you to calculate the volume of a unmarked canopy or might say you don't have sufficient space unless the canopy is marked.
Really its a AHJ call as to how they define 'sufficient space'.

"Canopies and outlet boxes taken together shall provide sufficient space so that luminaire conductors and their connecting devices are capable of being installed in accordance with 314.16"