Insulating Electrical Sockets/Boxes

[Phishin]

What do you guys find the best procedure is to seal around electrical boxes? I have a decent draft flowing out the boxes on my exterior walls.

Many reviews love and hate foam gaskets for the covers. Some people warn of using spray foam around them as well. What to BITOG'ers do?

Almost all the boxes I want to fix out are single outlets. They have a receptacle to plug in an appliance on the top and bottom (standard outlets). Should I remove the receptacle and foam the inside of the box to seal the holes where the wires come into the box? Or just simply spray foam around the edge of the box to create a seal against the dry wall? Add a foam gasket as well?

Looking for advice. I'm looking to do my whole house tonight after work. I'll end up doing the interior walls as well.

 

[Corvette Owner]

Most people recommend sealing any large cracks between drywall and OUTSIDE of electrical box with a latex sealant/chaulk ( non expanding and easy to clean up) and using gaskets and child outlet protectors.

If the gasket covers the drywall, there is no need to use sealant.

This should take care of air infiltration.

 

[daman]

I understand what he is saying air is coming in from INSIDE the box, I have the same issue.

 

[The_Jeff]

I would not use spray foam, I'd hate to introduce something flammable inside an outlet box. They are supposed to have just air.

If your walls have "pink fiberglass" I'd seperate a small clump of that and stuff it in the back of the box around and through the romex clamp with an appropriate tool-- flat screwdriver, bent butter knife, etc. That way if your house burns down it would seem plausible that the fiberglass just "worked itself in there".

If your drywall is sloppy around the box (are we talking blue plastic carlon boxes?) you might be able to get a coat hanger in there and pull the big wad of existing insulation behind the box if you can see it was sloppilly stuffed around it instead.

 

[Inspecktor]

Also, use safety plugs in outlets, air often flows out through the plug slots.

 

[Dufus2]

Years ago there were some foam gaskets to place under the wall plates to slow drafts. You may try some felt to slow the air draft from coming into your home.

 

[EdwardC]

I would probably use some kind of spray foam like you mentioned. A latex based foam, like this: http://www.dap.com/product_details.aspx?BrandID=20&SubcatID=4 should work, and expand minimally. The TDS even mentions the use around electrical junction boxes. The straw allows you to get behind the j-box easily to fill that gap.

I wouldn't try to insulate inside the box.

Edit:
Looks like Dow has a Great Stuff branded expanding foam that's suppose to be more fire proof that they suggest for this application: http://greatstuff.dow.com/where-to-use/living-space/electrical-outlets/

 

[DBMaster]

I am satisfied with the performance of the foam gaskets I installed fifteen years ago on exterior wall outlets. They work fine.

 

[IndyIan]

Do you have a lot of vacuum on the house for some reason? We have our boxes in plastic air blocker boxes, taped to the vapor barrier and still get a little leakage on some with the woodstove going, as it needs makeup air from outside somewhere in the house.

 

[Phishin]

Originally Posted By: IndyIan
Do you have a lot of vacuum on the house for some reason?


Possibly. Last year I had an energy audit done on my home. He used a gauge of some kind to measure the velocity of air coming off the hot water heater before it enters into the exhaust ductwork. He said my house was sealed really well based on those numbers alone.

I'm going to get some spray foam tonight and see what I can do. I'll skip the gaskets for now, until I see the results of just using foam. Right now, the flow coming out a few of the receptacles is astonishing.

 

[Pop_Rivit]

If it were mine I'd drill 4 small holes, one on each side of the electrical box. Then take a can of expanding spray foam insulation and stick the spray tube in each hole. Spray liberally around each of the 4 sides of the box. Pull the tube out as you continue spraying and stop just before then end of the tube exits the hole. You should be able to seal not only the box, but also the edge where the box meets the drywall. Then touch up the hole with a little drywall compound and touch up the paint. If the gap between the drywall and the edge of the box is large enough, you can use that and forgo the drilled holes.

 

[HerrStig]

No connection is truly ZERO ohms. I (squared) X R losses can heat up the inside of the box. Best be careful in high current applications.

 

[sleddriver]

I installed the foam gaskets about 30 yrs ago on both switches and outlets. I also had to seal up some bad drywall/switchbox junctions. Though gaskets will take care of this, I used regular caulk here.

A few years back, I climbed in the attic and used foam + caulk (depending on the size of the hole) to seal up all the wire/plumbing penetrations through the top plates. This prevents cold attic air from sinking down your interior wall cavities. I also used foam board to seal off several open fur-downs (thanks Mr. "custom builder") that were open to cold attic air. Result? No more cold interior walls.

Re: Can foam...I like Hilti the best. You can actually use the can for several weeks after initial use compared to the other stuff which soon hardens after you use it. More economical.

 

[sleddriver]

Originally Posted By: Phishin
Originally Posted By: IndyIan
Do you have a lot of vacuum on the house for some reason?

Possibly. Last year I had an energy audit done on my home. He used a gauge of some kind to measure the velocity of air coming off the hot water heater before it enters into the exhaust ductwork. He said my house was sealed really well based on those numbers alone.

I'm going to get some spray foam tonight and see what I can do. I'll skip the gaskets for now, until I see the results of just using foam. Right now, the flow coming out a few of the receptacles is astonishing.

I don't understand the contradiction...previous testing revealed your house was "sealed really well", yet "the flow coming out a few of the receptacles is astonishing?" Doesn't make sense.

 

[Corvette Owner]

Don't understand why you are against the foam gaskets made for this? Try them they work really good! Then add the baby socket plugs to stop Air coming through those plug openings.