On Thu, 16 May 2019 06:31:44 -0700 (PDT), trader_4
wrote:

On Thursday, May 16, 2019 at 9:29:04 AM UTC-4, trader_4 wrote:
On Thursday, May 16, 2019 at 9:08:33 AM UTC-4, Biff Tannen wrote:
On 5/16/19 8:56 AM, Home Guy wrote:
I'm installing a couple ceiling fans in adjacent roons and was going to install the switch controls on opposite sides of the same wall, at the same location.

I'm thinking there is, of course, such a thing as a two-sided, through-wall outlet box.Â* Because 2x4's and drywall are standardized enough so you can make a box that will work for this application -right?

I do some web-searching and come across some post in some DYI forum from 10+ years ago where someone is asking the same question, and no, for some reason there is no such box.

I also come across this:

https://www.youtube.com/watch?v=pg7XdoBnKjU

Seems to be a video made by someone who patented a through-wall double-sided box.Â* Really?Â* A patent for the obvious?

It's crazy that these don't exist.


I like the idea but...

Wire fill limits?

Would there be enough depth for two back-to-back switches?

Probably. 3.5+.5+.5=4.5. I think a switch is ~1.5", a regular box is 3"
deep, so you'd gain 1.5" of depth, but then you also have another switch
which takes up that space. Sounds like two switches with the associated
wiring with about the same empty space as a one switch box.

That didn't come out quite right. I was focused on the "wire fill limits?"
and by "probably" I meant there probably is a wire fill limit problem, as per
the math.


A 2x4x4.5 (3.5" of wood and an inch of drywall) is 36 cu/in and that
would support a wire count of 16 14 ga "wires" and 14 12 ga "wires".
2 devices eat 4 of those "wires" and the grounds all eat a total of 1.
that gives you 9 #12s or 11 # 14s. That should be plenty.

A possible reason the building/fire code. They really want to maintain
that 15 minute rating you get with drywall. In fact some jurisdictions
get funny about having boxes in the same bay serving opposite sides of
the wall, depending on the requirement.

You could always make this box you want by ganging three 1.5"
extension rings together.