ECN Forum Forums Photo Discussion Forums Photos for General Discussion Foam in Boxes

(submitted by Joe Tedesco)

Kinda wrecks the old box fill calculations, don't it.

how do we calculate foam into box fill calculations?

Easy

4 x 4 x 1-1/2 Box = 21 cu in per 314.16 (A)

3 #12 conductor @ 2.25 cu in each = 6.75 cu in.

1 device @ 2 x 2.25 cu in = 4.5 cu in

1 Foam job @ 9.75 cu in

Perfect fit

4 x 4 x 1-1/2 Box = 21 cu in per 314.16 (A)

3 #12 conductor @ 2.25 cu in each = 6.75 cu in.

1 device @ 2 x 2.25 cu in = 4.5 cu in

1 Foam job @ 9.75 cu in
_________________________________________________

= 0.00 cu in + Fire Hazzard x (10)2 = Complete Violation & Installer must be shot.

But it keeps the recept. and terminals at a constant toasty temperature....what's the problem?

And it eliminates that annoying loose device wiggle, too.

Constantly amazes me how dumb some people can be...

Boy!,
I bet that was hard to get out!.
What's more concerning, is the stuff that Expanding foam is made out of.

I see what looking like pink fiberglass insulation the the lower corner of the box.. is there actually a box there? or just a mud ring?

"I see what looking like pink fiberglass insulation the the lower corner of the box.. is there actually a box there? or just a mud ring?"

Is there even a box here?

[This message has been edited by Theelectrikid (edited 08-07-2005).]

Yes there is a box there. You will notice that the insulation is actually on the outside of the mudring. What I'm wondering now is where the vapor barrier is. I wonder if somebody stuffed that in there at a later point to plug a leak. It looks like weatherstripping was a huge concern back when this place was renovated.

The reason there is a mudring is because the property is piped and most common pipe installs here use 4x4 boxes with mudrings. There are a few single-gang-with-knockout style boxes, but those are usually at the end of switch loops and only contain two #14s.

Don't let the lack of paint on the receptacle throw you off much either as the maintenance guy of the apartment was not in the habit of removing plates to paint. Almost every plate has a small ring of paint around it. That install has been there, foam and all, I would guess, about five years.

It is unknown to me if the other 166 suites in the building are identical with respect to foaming receptacles on outside walls. I assume so. Some of the suite designs that were missing receptacles in certain places (12 foot rule) had them added using wiremold, so whatever work was done, it obviously had to be made to conform to code at the time of renovation.

I should show you guys a very interesting install that I also snapped a picture of from the same complex. One type of suite had a bedroom receptacle directly behind the fridge, and that recept and the fridge recept were in a single box with a mudring on each side. With both plates off you can look through into the other room! Never, ever seen anything like that before but it was clearly original.

Honestly, aside from the foam, i'd say the wiring as a whole is actually pretty good. All of the devices are P&S, not back-stabbed, etc. Not your standard corner cutting, 35 cent, back stabbed, home depot special--which is much more common.

[This message has been edited by jdadamo (edited 08-07-2005).]