Box fill

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nizak

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I'm looking at a Raco product, part #404.It is a 1" deep bracketed metal box. It has a capacity of 6.5 cu/in.

I can't see where any combination of wire and device will fit in this and be code compliant.

1-14/2 NM cable= 6 cu/in. (2) insulated conductors and (1) egc.
1- duplex receptacle = 2 cu/in.

What am I figuring wrong?

Thanks
 
nizak said:
I'm looking at a Raco product, part #404.It is a 1" deep bracketed metal box. It has a capacity of 6.5 cu/in.

I can't see where any combination of wire and device will fit in this and be code compliant.

1-14/2 NM cable= 6 cu/in. (2) insulated conductors and (1) egc.
1- duplex receptacle = 2 cu/in.

What am I figuring wrong?

Thanks
Click to expand...
Please pardon the nitpick: 1 - duplex receptacle = conductor count of 2, or, 4 cu/in.

I don't think you are missing anything. The only way this box can be used is with a surface extension of some sort.
 
nizak said:
I'm looking at a Raco product, part #404.It is a 1" deep bracketed metal box. It has a capacity of 6.5 cu/in.

I can't see where any combination of wire and device will fit in this and be code compliant.

1-14/2 NM cable= 6 cu/in. (2) insulated conductors and (1) egc.
1- duplex receptacle = 2 cu/in.

What am I figuring wrong?

Thanks
Click to expand...
Are you sure it's not 16 cuun?

Sent from my SM-T350 using Tapatalk
 
I don't see any application using Class 1 Wiring, however, one could use this box for a RJ-45 Jack or similar.
 
"RACO® Shallow switch boxes are made for use with furring strips and 1/4" paneling."

Says so right in the catalog. :lol: 6.5cu/in is correct. You see them a lot in old houses with paneling over furring strips on the basement walls. What code cycle did we have to include the device when calculating box fill?

-Hal
 
hbiss said:
What code cycle did we have to include the device when calculating box fill?
Click to expand...

Hal, that Code cycle goes back before the 1965 NEC, and it was a single conductor count per yoke. Then, in the early '90s, as a result of full body GFCI, and dimmers, and other electronic devices, the count was increased to two.
 
Funny that those boxes even have an internal clamp which means that you need to further reduce the volume by one conductor. I could see using that with a Wiremold collar style box over it or for something like a thermostat.
raco-404-1-deep-switch-electrical-box-welded-with-side-stud-bracket-1-1-2-end-knockout-2-nmsc-cable-clamps-3-3-4-x-2_29897223.jpeg
 
MiElectrician said:
What about using smart mc with an aluminum bonding wire instead of the ground and using grounding receptacles
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Still not enough volume.

ungrounded conductor
grounded conductor
device counts as two conductors

4x2=8 cubic inches needed.

self grounding receptacles don't make any difference as a grounding pigtail that doesn't leave the box doesn't need to be counted.

Before NEC changed the device count to 2 conductors - it would have worked, presuming there were no internal clamps or anything else that needs counted.
 
kwired said:
Still not enough volume.

ungrounded conductor
grounded conductor
device counts as two conductors

4x2=8 cubic inches needed.

self grounding receptacles don't make any difference as a grounding pigtail that doesn't leave the box doesn't need to be counted.

Before NEC changed the device count to 2 conductors - it would have worked, presuming there were no internal clamps or anything else that needs counted.
Click to expand...
Don't use this Box! Dead end only.

Sent from my SM-T350 using Tapatalk
 
MiElectrician said:
What about using smart mc with an aluminum bonding wire instead of the ground and using grounding receptacles
Click to expand...

You'd have to show that the box integral clamps are listed for grounding termination of MC cable, which I highly doubt the clamps are.

But, even with MC-AP, #14, you'd still need 10 cubic inches in that 6.5 cubic inch box.
 
I have used boxes like that for light switches where the architect specified dual pocket doors for the room entrance and there was not enough clearance between wall and door for a standard box. Had to put a surface wiring extension box on top of it, of course....
 
Santa49 said:
Too bad this isn't 1959. I believe this might work according to NEC 1959.
Click to expand...

Boy how times (and the Code) have changed. This morning's coffee and my curiosity got me to open my copy of the '59 NEC. The rule on the number of conductors in a box is located in 370-6.

1959 NEC Table 370-6(a-1) lists the shallowest wall case as 2 x 1-3/4 x 2-3/4 and allows a maximum of 5 #14 conductors (with no device or clamp).

Below Table 370-6(a-1) there is an exception: Where there is not sufficient space for a deeper box, four No. 14 Awg conductors may enter a box provided with cable clamps and containing one or more devices on a single mounting strap.

So, there you have it. What, today, calculates to 16 cubic inches (4-#14 conductors, EGC, clamp, and device) was permitted in the OP box of 6.4 cubic inch capacity back in the days of the 1959 NEC when NM cable did not have an EGC, if "there [was] not sufficient space for a deeper box".
 
JFletcher said:
Those are worthless. Heck, if I had a wall that shallow, I'd just buy self-contained switches and receptacles like trailers use and be done with it.
Click to expand...
I haven't seen one of those devices in a while, but seems they need more depth then the box in question has.
 
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