Can You Put Expanding Foam Around Wires?

Expanding foam is great for stopping air flow, bugs, and providing great insulation to regulate your home. Some concerns come with using it though. Its expanding nature can cause damage to certain things if done improperly.

You can put expanding foam around wires. You will need to be cautious and use the proper type of foam before you apply it. You will also need to secure any wires that may be moved when the foam expands.

Securing Wires

While expanding foam won’t cause any damage to your wires, if you do not properly secure the wires beforehand they may pull when the foam expands.

Wires being pulled can cause shorts and make it difficult to locate wires if you are using expanding foam to insulate large portions of your house.

If you are only insulating an electrical outlet or other small section all you have to do is spray the expanding foam slowly and adjust the wires as you go. Don’t pull the wires, just move them gently.

If you are using spray foam to insulate large sections then it is a good idea to use screw-in fasteners to secure your wires. Place them often. Between three and six feet should provide adequate security.

Also, properly secure wires inside any electrical outlet before you spray large amounts of foam. You might even consider spraying foam around the box before the rest of the building.

If you do that let the foam cure before doing the rest of the building. That won’t stop unsecured wires from being pulled but will provide a safe zone where that section of wire won’t experience anything when you spray the majority of the foam.

Types Of Foam

There are two types of foam. Sealing foam and insulating foam. While these are technically very similar the application of them is very different.

Sealing foam is the kind that comes in small cans. It’s generally used by self-application for small projects like replacing windows or sealing electrical outlets. It is not flame retardant so normally it goes inside walls.

When picking sealing foams you have plenty of options. Really any of them will work for electric outlets and for around wires. Any that are high expansion foams you will need to apply more carefully. Though it probably wouldn’t cause any problems, any careless application could result in wire movement and potential damage.

Insulating foams are going to require wire securing. Insulating foams are used to cover large areas when insulating a home. These come in two types. Half pound and two-pound. The two-pound foam shouldn’t give you any trouble because it doesn’t expand very much.

Half-pound foams may cause you a lot of trouble. These expand a lot very quickly. So before you apply half-pound expanding foam make sure your wires are properly secured with fasteners.

Insulating foams are often fire retardent as well, which means you shouldn’t have any worries in case your wires do get pulled and short out. Chances are you would notice the short pretty fast and get it fixed.

If you do need to fix a wire after the expanding foam has cured you will need to cut the foam away and look for the problem wire.

Proper Application

Proper application of sealing foams is a pretty straightforward process. Protecting your wires can be a little more tricky.

If you are sealing an electrical outlet then you will need to apply foam a few times. Follow this process.

You will need expanding foam, nozzle (most cans come with their own), and soft plastic tubing.

  • Flip breaker to Off
  • Wait a few minutes for electrical dissipation
  • Unscrew faceplate and outlet
  • Gently pull the outlet out
  • Grab a spray can nozzle
  • Optional: Attach flexible tubing to the end of the nozzle (this will give you more control over where the foam goes)
  • Slowly spray back half, covering all holes
  • Wait for the foam to cure
  • Screw outlet back in
  • Spray foam around the socket (the box the outlet rests in)
  • Wait for it to cure
  • Screw on faceplate

It’s a little wordy and seems like it would take a long time. Sealing foam generally only takes a few minutes to cure though. So this process altogether would only take ten or fifteen minutes.

By doing it this way you can safely spray expanding foam around wires contained in an electrical outlet.

If you are applying to a hole the wire is going through all you need to do is apply the foam slowly to the hole. That shouldn’t pose any problem whatsoever.

Future Wiring

If you are planning on changing wire after expanding foam is applied, it could be quite the project. Expanding foam is an excellent adhesive, so it wouldn’t be something you can pull or scrape off. Depending on the type it could be very difficult.

Using sealing foam basically means you have to remove it the hard way if you change anything after it cures.

With a little forethought though we can avoid having any big problems with insulating foam. If you are planning on putting in any wire after a building has been insulated with expanding foam all you need to do is put conduit where your wire will be going before your spray.

Make sure you place the proper size conduit though. Use conduit big enough to allow for wire to be fed easily. PVC pipe would work well for this. The size would depend on how much wire you are planning on putting in.

Luckily wire feeds through plastic very easily. So putting the wire in after you spray won’t be an issue so long as you planned and put the proper size conduit in.

To Sum Up

Using expanding foam around wires is safe and easy. It poses no real issues and all you need to do to use expanding foam hassle-free is take a few precautions. Secure your wires, move them gently, and place conduits.

Keeping these things in mind will make the process easy and smoother.

Ricky Kesler

With all of the projects I've done over the years, you'd think that I work on my house full-time. But I actually enjoy other things like spending time outdoors and time with my family.

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