Pancake Boxes

[ptonsparky]

Probably here too, was trying to be conservative

Let's just say I'm always surprised when replacing fixtures to find a box.

I would almost expect it on homes, but we found some fixtures hung on a drive thru coffee without them. These were inspected buildings, not 5 years old at the time and fixtures were already falling off the facade. I don't think the owner liked the cost to install boxes and hang new fixtures. Real PIA after the fact.

 

[Hv&Lv]

Isn't the fixture required to be marked with a volume for it to be added to the box volume?

I'm a little out of the loop here, but doesn’t the exception allow for the fixture wires themselves (up to 4) to be omitted count here?

 

[hillbilly1]

I wouldn't go back and change, but would take drastic measures to prevent it happening in the future

(Around here, probly 35% of exterior lites are installed without boxes)

Probably more like 75%. Most are just stubbed out, box (if) added later after siding is put up. Especially lap siding, so the fixture will be straight.

 

[electrofelon]

They make a 1/2 in 3o pancake extension to build your own.

You are proposing to use a 3.5" pancake on a 4" pancake as an extension ring? How would that work? How about taking another 4" and pinching out the back to say 3.5"?

 

[infinity]

I'm a little out of the loop here, but doesn’t the exception allow for the fixture wires themselves (up to 4) to be omitted count here?

Yes fixture wires smaller than #14 but not the branch circuit wires contained in the OP's (2)-14/2 cables

 

[Hv&Lv]

Yes fixture wires smaller than #14 but not the branch circuit wires contained in the OP's (2)-14/2 cables

Ahhh. (1) 14/2, not two of them..
told you I was out of my zone a little..

 

[curt swartz]

In my area virtually all exterior walls have 1/2 shear (plywood or OSB). 7/8" stucco is the most common finish next is some form of Hardie siding.

For stucco if the exterior light lands on a stud/post and is single ended I use a 4/0 pancake. If there will be 2 cables I drill a 4" hole in the shear and chisel 1/4" out of the stud so a standard 4/0 1-5/8 deep box can be used.

For siding the GC's install 2X4 blocks slightly larger than the fixture canopy on top of the shear. The same 4/0 1-5/8 deep box can be installed directly to the shear.

For Stucco that has no structural member in the way I drill a 4" hole and use an NM 4/0 bar hanger box.

 

[letgomywago]

You are proposing to use a 3.5" pancake on a 4" pancake as an extension ring? How would that work? How about taking another 4" and pinching out the back to say 3.5"?

No use a 3.5 with a 3.5 for enough volume

 

[electrofelon]

No use a 3.5 with a 3.5 for enough volume

Looks like you can get a 4" ER too. I didn't know they made one.

 

[fishin' electrician]

If I was given a million dollars every time I saw a pancake box be an actual problem,

I would still be the thousandaire that I am.

 

[electrofelon]

If I was given a million dollars every time I saw a pancake box be an actual problem,

I would still be the thousandaire that I am.

You are fortunate, they frequently cause problems for me. Just last week I had drill into the stud and chisel out to recess the box a bit. It was one of those fixtures where to fix your bar must mount flush to the wall in the fixture screws in from the sides.

 

[rc/retired]

You are fortunate, they frequently cause problems for me. Just last week I had drill into the stud and chisel out to recess the box a bit. It was one of those fixtures where to fix your bar must mount flush to the wall in the fixture screws in from the sides.

Is that a box problem or fixture problem?

Ron

 

[electrofelon]

Is that a box problem or fixture problem?

Ron

It is what it is. Sure it wouldn't have been a problem if the client chose another fixture, also wouldn't have been a problem if there was a standard box there. Some fixtures don't work well with pancake boxes.

 

[rc/retired]

It is what it is. Sure it wouldn't have been a problem if the client chose another fixture, also wouldn't have been a problem if there was a standard box there. Some fixtures don't work well with pancake boxes.

Can't argue that one.

Ron

 

[readydave8]

If I was given a million dollars every time I saw a pancake box be an actual problem,

I would still be the thousandaire that I am.

Except when light hangs on chain. Go to truck, shorten nipple with m12 Bandsaw. Now you've got 1/2" to bend fixture wires, if tight in nipple may be pulling it through 1/2" at a time

 

[AC\DC]

If there pancake in siding could put medallion and extension ring would look better anyway.

Just roughed in two fan with 14-3 x2 in one. He questioned told them they are blocking out and I’ll use extension. Worked. They are market with cubic inch( talking about the cheap plastic ones)

 

[fishin' electrician]

I've had simple items that were difficult to install and difficult items that were simple to install.

I was referring to the box, not the installation. While it's certainly possible, I've never seen a fire or shock attributed to the use of a pancake box.

 

[Rick 0920]

See post #2 if your fixture has a canopy. I always used LX boxes and listed concrete clips. These fixtures can be supported by 6-32's. I always heard that you can support fixtures weighing less than 6 pounds from single-gang boxes but I don't see that in the Code anywhere. 410.30 just says that if the fixture is over 6 pounds it can't be supported by the screw shell.

 

[garbo]

One of my guys has been installing pancake boxes on exterior lights. The problem is that there are two 14-2 cables in some of these. I just found out about this recently, and some of these jobs are done. Would you move on, or try to go back and fix it? Everything has been inspected.

Awhile ago at a CEU class the inspector/instructor stated that if you use the typical two screw NM cable to the rear of a 1/2" deep pancake box you would not have enough cubic inches to satisfy the NEC . Also told us that we should only use UF cable to feed outdoor luminaries because NM cable is not rated for damp locations. Like others posters stated never saw cubic inches provided by luminare domes.

 

[infinity]

Also told us that we should only use UF cable to feed outdoor luminaries because NM cable is not rated for damp locations.

The interior of the box is not by NEC definition a damp location. That one does come up quite a bit.