Metal Vs Plastic Electrical Boxes | Avoid This Common DIY Mistake

As a child, my dad always made me watch him working around the house, so, as he put it, I would know how to fix things when I grew up. Dad was a custodian in a public school; had something called a black seal fireman's certification, and had learned all sorts of electrical, plumbing, and construction skills from the 'real' professionals during his lifetime, because he watched them, when they came to work on the systems at his school. It makes me so happy, to know that he really did know what he was doing, and how important it was to him, to make sure that I learned how to do things the right way. I watch your videos, and remember my dad, teaching me how to do so many things correctly and up to code, even though he wasn't a professional electrician. So I thank you, and I thank my dad, for the knowledge that you both pass along to me, so I won't burn my house down.

What I do with metal boxes is make the pigtails to 7" to allow me to wrap the bare ground wire around the green screw in the box; then, rest of the bare wire is attached to the ground screw to the outlet ground screw. That way you do not need the additional green pigtail and the Wago splice

Keep in mind that some jurisdictions require metal boxes and EMT per local code, such as Chicago and the surrounding area. Always check with your municipality on what they allow!

The metal box is far superior to the plastic box. Any real electrician would know to pigtail a ground wire before installing the outlet. But even for a novice who didn't know that just how is anyone going to come in contact with a hot box once it's behind the sheetrock? The best thing about the 1900 box is if at a later date you need additional outlets as in behind an entertainment system you cut the rock out a bit larger, remove the single gang ring and install a two gang ring and then add an additional plug. If you cut out carefully you can still hide the work behind a standard two gang outlet cover. I have installed thousands and thousands of outlets in my career and have never installed a single outlet or switch that I didn't wrap in tape. It's easy enough for the ground wire to touch the hot screws if you don't fold the wires in properly. And lastly I would never use anything in an outlet box except for a quality wire nut. I've had arguments over the years on which wire nut is better but no one I know has ever use a spring type device like a wago for anything beyond fixture wires. Age, current and load make most devices fail over years but wirenuts and yes the older crimp copper or steel buccanans are far superior to any type of lever or spring tension device. By code even wirenuts are required to have the wires twisted together to form a good connection not dependent on the wire nut.

I'm a commercial electrician, since I usually use metal boxes, I'd prefer the metal over plastic. They make push in plastic bushings for romex that is a bit easier for the DIYer to install their romex into the boxes; that would save them the effort of fiddling around with locknuts. I really like that you used the 2 1/8" deep box over the 1 1/2" boxes, if I can get away with using deep boxes like that, I always do. Quick tip for DIYers, if you don't want to mess with pigtails, rather than pulling more ground wire out of the romex, which shrinks the ground on the other side of the wire, give yourself enough space to attach that ground to both the box and the device. Typically when doing a rough-in, I like to give myself about 18" of wire at each box, yes there's a little waste at the end, but wire can always be cut to length and it gives enough ground wire for me to tie that ground onto the ground screw and make that bond, rather than cutting separate pigtails. I'm also a big fan of "fold as you go" so you're not fighting to install that device, it's not a big issue with the box you've got and a single device that you're installing, but if there's a possibility of adding another device in the future or the box is smaller, it's always a good habit to leave yourself extra space in the box, it also looks much neater and it will allown that device to go in straight. Either way, good video.

I've been and Electrician for over 40 years. Nice information. I use ALL metal boxes ALL the time. I am retired now in Arizona and do mostly old work with romex, as such the old work metal box comes with Romex clamps already installed. The main reason I learned to use metal boxes is NYC Code. The code was written in case the outlet catches fire the spark or fire would be contained. I tape EVERY OUTLET just in case and bare conductor has a chance of hitting a screw ect and so the next guy doesnt get zapped. Loved your information... and as per NYC Code .. you take the ground conductor and wrap it around the ground screw in the box and as one continuous wire go to the ground on the outlet Have a great day and keep up the good work

For grounding the box, a common thing I've seen in homes is to wrap the Romex's ground wire around the ground screw and then connect it to the outlet. Fewer wires makes for more space in the box, which is helpful on single-outlet metal boxes.

I use metal boxes almost exclusively. The one exception I made was when installing a pair of duplex outlets between my garage door openings on the inside; there was a gap such that the heavy-duty plastic box bridged it easily with the mounting ears.

If you have tile/backsplash an adjustable box is a great option. You just turn a screw to align the box to the exact finished face of the wall.

My dad built the house I grew up in back in 1957 and all the boxes were metal and the wiring was BX. So, when I did retrofits, I learned to work with both effectively. I do like the added strength of metal boxes.

I agree with everything you said, including when to use tape. Good point about ensuring the wires don't pressure the outlet from the side, to skew its position when mounting for the cover plate.

I still like the elegance of a metal box. They make plastic inserts for metal boxes allowing you to push in the wire.

I may be mistaken but I believe Canadian code does not allow using a separate wire to bond the metal box as you show. Instead the ground coming into the box must go to the box ground first and then continue to the outlet ground. So when bringing the cable into the box you plan on the ground wire hitting the ground screw first. If you plan this it works out elegantly most of the time. You "can" depend on the screw carrying the ground from the box to the outlet, but I prefer to have a solid connection. If you do a "workman" like job, you don't need to tape over the terminals.

I've been in my house over 18 years now (not a cheap one) and all the boxes are plastic. While going through to upgrade to newer switches and outlets, I'm finding that nearly 1/3rd of the boxes have stripped or broken threads, or they have come loose from the studs. Probably shoddy original work. There were many times when I had to hold the outlet cover in while pulling out power cords from the outlet. I guess I just like the solid feel of a metal box.

I just did this same installation on a meatal box. MY Home was built 1950. No grounds in any boxes. I ran pig tail and wall to ground to box. Good education. Thank you for the help.

I really like the Southwire MSB series boxes for old work; they mount to a stud, which is a lot better than trusting drywall and little tabs. Thanks for your work!

I am a commercial electrician, t Metal boxes are all I have ever used including in residential. I used a ground wire pig tail with a green screw in ever box. Ever Metal box is grounded to the ground wire in the MC 12-2 or romex 12-2. Never had a problem. Always passed rough in inspection.

When fishing into a metal box knockout you can use a plastic bashing which can be installed from inside the box. The bushings typical have retention ears built in to keep the wire from pulling out.

I use metal boxes in basements, attics, and garages. I wrap receptacles, and switches in a metal box with electrical tape before installing.

Thanks! I’ve always used metal boxes on my many many home remodeling projects, but your vid demonstrated that the time requirement is much less with plastic boxes. Yes plastic is flimsy, but once you finish your walls with drywall and cover plates, you have a fairly sturdy, non conductive assembly with less labor. I get it!! I’m getting ready for a whole house (knob and tube) replacement and I think I’ll use plastic for switches and receptacles and assign metal for areas that will not have wall coverings, such as basements, crawls and unfinished walls, such as accessory structures. Thanks for the quick, concise, well prepared vid! You’re the best!!