Old Work Box: Difference between revisions
(→Round) |
(→Round) |
||
| Line 10: | Line 10: | ||
=Round= | =Round= | ||
*{{check}}Admissible parts - For resi, I prefer the 18 cu.in. 4” round, #C1-18 Slater boxes. A 3-3/4” hole saw is a perfect fit for it. | There is a known bug in most old work boxes - the clamps are too close to the edge and these must be cut out while using a hole saw for the round diameter. | ||
*{{check}}Admissible parts - ''For resi, I prefer the 18 cu.in. 4” round, #C1-18 Slater boxes. A 3-3/4” hole saw is a perfect fit for it. | |||
The Slater box is actually rated for 20lb fixture support, so I really like to use these for wall mount fixtures if the canopy will cover them. | The Slater box is actually rated for 20lb fixture support, so I really like to use these for wall mount fixtures if the canopy will cover them. | ||
The old standard 14 cu.in. 3-1/2” round T&B phenolic boxes are still great for lightweight low profile applications having only a few wires. A 3-5/8” hole saw allows the for the C-clamp and ears to set in perfectly. | The old standard 14 cu.in. 3-1/2” round T&B phenolic boxes are still great for lightweight low profile applications having only a few wires. A 3-5/8” hole saw allows the for the C-clamp and ears to set in perfectly. | ||
Revision as of 04:38, 12 May 2024
About
For cutouts in plywood, as opposed to frame mounted receptacles.
https://www.amazon.com/Lamson-B120R-Carlon-PVC-Outlet/dp/B00002N5FQ
Old work box in 60 seconds:
https://www.youtube.com/watch?v=WON0DKCe5P8
Round
There is a known bug in most old work boxes - the clamps are too close to the edge and these must be cut out while using a hole saw for the round diameter.
Admissible parts - For resi, I prefer the 18 cu.in. 4” round, #C1-18 Slater boxes. A 3-3/4” hole saw is a perfect fit for it.
The Slater box is actually rated for 20lb fixture support, so I really like to use these for wall mount fixtures if the canopy will cover them. The old standard 14 cu.in. 3-1/2” round T&B phenolic boxes are still great for lightweight low profile applications having only a few wires. A 3-5/8” hole saw allows the for the C-clamp and ears to set in perfectly.
- Slater - C1-18 box - [1]. Note that the clamp screws are recessed, allowing full coverage of flange with screws, up to 20 lb - no need for keyhole saw tab fixing.
- Cantex seems ok - [2]
Sourcing
Dimensions
Note on dimensions - the outlet mounting screws form the outer edge. These screws are protrusions, or inside the box, but their outer dimension defines the height of the box. That appears to be 3-5/8". It is safe to do 3-3/4" as the 4 front tabs are larger than this. The locking tabs on the back are even larger.
It seems safe that 3.75 is a safe height of cutout, and 2-3/8" is a safe width (widths all appear to be 2.25").
- 3-7/8-Inch Length by 2-3/8 [3]
- 4-1/8 x 2-1/4 [4]
- 2-3/4 in x 2-1/4 in [5]
- 2.75 x 2.25 x 4.3 [6]
- 3.65 x 2.3 x 4.3 [7]
- 2.25 x 4.38 x 2.75 [8]
Allowed in New Construction
https://forums.mikeholt.com/threads/installation-of-old-work-boxes-in-new-construction.61773/
Exceptions
From [9]
Just a heads up, if the wall is fire rated the box must be secured to the stud regardless of the box listing. This is a building code issue not a electrical code issue.
I have no idea if the opening posters wall is fire rated.