Outlet Boxes - Metal or Plastic?

[glenn bradley]

Won't we all be happy when Glenn finally finishes his sub panel and we can get back to talking wood?

My plan involves a few different outlet box locations:

Some will be in a wall, stucco exterior wall, wood studs, drywall interior to be added after electrical.

Some will be in a wall, stucco exterior, wood studs, OSB interior to be added after electrical.

Some will be in the "ceiling" mounted to wood joists, no exterior or interior wall.

So, plastic boxes or metal boxes or a mix?

[Matt Meiser]

In my shop, all the in-wall ones are plastic, mainly because they are so easy to use, no knockouts and cable clamps to deal with. Anything surface mounted is metal with 1/2" EMT running to it, except for my welder recptacle which needed larger conduit because of the size of the wire running to it (4-#10 if I remember correctly.) There I used plastic conduit/box because it was easier to work with.

[glenn bradley]

In my shop, all the in-wall ones are plastic, mainly because they are so easy to use, no knockouts and cable clamps to deal with. Anything surface mounted is metal with 1/2" EMT running to it, except for my welder recptacle which needed larger conduit because of the size of the wire running to it (4-#10 if I remember correctly.) There I used plastic conduit/box because it was easier to work with.

Thanks for the quick reply Matt. What are your interior walls made of if you have them?

[Jim O'Dell]

I used plastic exclusively in walls and ceiling. I have about 20 in the ceiling, and about 22 in the walls. Most all the wall receptacles are on the outside walls I think 4 may be on inside walls (it's only 14' long, and has a 6' door opening in it). I like plastic because it is non conductive. Just an extra measure of safety for me. Jim.

[Jeff Raymond]

Here's a quick tip having just built a new shop.

Use nylon face plates. They don't crack like the plastic ones.

Good luck!

[John Terefenko]

I like to use metal for just the oposite reason because they are conductive. Any shorts or grounds are in the box are known well before me. Just a matter of choice. Do you like Chevys or Fords???

[Stan Welborn]

All mine in the ceiling and walls are plastic. Never really thought about it.

[Gene Jordan]

Glenn,
I use metal boxes exclusively because of strength. If you ever have to change a switch or an outlet and have the screw strip out that enters the (plastic) box you will see what I mean. Almost every metal box that I've seen will have a tapped hole (sometimes on a raised boss) for a ground screw to make the metal enclosure safe from shock hazard. I always run the ground to the metal ground screw and then to the swith or outlet, in essence grounding both items together. At times the larger guage (usually 10 AWG or larger)wire is pretty stiff and if there is a kink in the conductor behind whatever you are entering into the box, you can be fairly confident that the screw will not strip at the slightest resistance when using a metal box.
Just my 2 cents worth.

[David G Baker]

I use both plastic and metal depending on the type of material the box is going to mounted in or on, the number of wires in the box and what I have on hand.

[Michael Lutz]

I would use metal. I have been replacing the original plastic ones in my house for two reasons: the screws strip out in the plastic boxes and the metal ones are sturdier than the plastic ones.

Mike

[Kent Fitzgerald]

I like the heavy duty plastic boxes (e.g., Carlon Super Blue). They have a lot of capacity (up to 22 cu in single gang), retain screws well, and if you did manage to strip a screw, there's enough beef to replace it with a larger size.

[Kent Fitzgerald]

Or metal cover plates. I found some nice Pass & Seymour stainless steel plates. While I'm no interior designer, I think the gray devices and SS plates have a pretty cool industrial look.

[Mike Emde]

I have found the plastic boxes to be more user friendly, bringing cable into the box and mounting is easier. Just remember when putting any boxes on your outside walls that you use insulated boxes and vapour barrier boxes. You can buy a sleeve the goes over box that tapes onto your vapour barrier keeps the draft out.
i remember working on our last home and replacing a damaged plugin and it was a steel box. Depending what kindof boxes you use some are clamped together well this one came apart in the wall needless to say it was an interesting project

Best of luck
Mike Emde

[Matt Meiser]

What are your interior walls made of if you have them?

7/16" OSB, painted white.

[Greg Crawford]

Again it's the Chevy or Ford thing. I like metal for strength (I also use the SS plates for durability), but they are more work. I try to screw them to framing members with drywall screws so they don't move around like plastic boxes will. Remember, a metal box is required to be grounded so the breaker will trip to prevent a person from being shocked if they touch a metal box that is in contact with a live wire. The grounding pigtails can be a real pain.