Plastic Device Box's

[Teken]

Is there a reason people use the plastic device box's over the standard metal one's?

Please give me a example or situation where you would opt to use one over the other.

Also if someone can point me to a on line retailer which sells them for a good price that would be appreciated.

 

[Notch1988]

Are you talking about low voltage boxes?

 

[mrb]

plastic boxes with romex, metal boxes with conduit......

 

[Teken]

No, for 120 use . . .

 

[Shayne_B]

Cost & time = money.. Plastic boxes are quick to install, & the nails are already in them plus they have a plastic tab that holds the wire in place. where with a metal box that cost more, you would have to install a romex connector & provide you own nails! Plastic boxes are also available in one through four gang, metal boxes have to be screwed together.

 

[rhdave]

Not sure why people prefer plastic boxes. If I have to screw a machine screw into a box, plastic is always terrible. The metal ones are far more durable.

I prefer the metal ones, and yes, they come in 1-4 gang with romex clamps. I personally prefer the 2104 boxes. I usually just screw them to wood studs top & bottom. They also come with wing-type things attached for use with steel studs.

 

[osu69]

Ever try using a Rotozip to cut around a metal box? Plastic is the way to go for residential.

 

[Stuart in MN]

Cost & time = money.

There's the answer. Durability isn't an issue once they're installed and the wallboard is in place.

 

[Coach James]

I greatly dislike plastic boxes. In my building, I have had several where the screws that held outlets in place had stripped out the threads in the plastic. I was able to fix them, but I never had that problem with metal.

Coach

 

[Teken]

Is there any instance where you can not use these box's in a residential install? I live in a very cold area in Canada so would they be alright to be installed outside?

 

[Teken]

I have had several where the screws that held outlets in place had stripped out the threads in the plastic. I was able to fix them, but I never had that problem with metal.

Coach

Ahhhhhhhhhh, this is a deal breaker for me then . . . I can see those plastic tabs where you screw in the plate stripping or breaking off . . .

 

[tfi racing]

I don't like them one bit,but out here on the west coast they are used exclusively in residential,in Alberta you would get laughed out of town for using them.I suggest using what the locals use,that way a lot of unnecessary questions don't get asked,and the other trades don't have to adjust their tried and true methods.

 

[1969]

Metal boxes are far superior IMO. On exterior walls use VB1 thru VB4 depending on the need. (thin skins)

 

[Norcal]

The metal boxes shown above are horrible, w/ #3 being the absolute worst, that type was popular in the sixties & earlier & a PITA to deal with, 4 square box, AKA a "1900 box" & a plaster ring is the best IMO, using a ring 1/8" deeper then the finish drywall, 5/8" for 1/2" drywall & 3/4" for 5/8" drywall. Plastic is used due to low cost, EZ to install & no need for grounding, w/ tract home construction everything is bottom dollar so whatever is cheap & quick because they are built & wired as cheap as they can get away with. (I refuse to say they are built to minimum code).

 

[cowboyjosh]

I've never built a house that didn't have plastic boxes; nor have I seen a custom or tract home built in Colorado, Arizona, Ohio, Florida, California, and Hawaii (all states I have family or friends) newer then 25 years that had metal boxes; I know of no electrician including myself that use them (metal boxes) in new residential construction. One of the only places that requires metal boxes is because they require conduit in residential, is in and around Chicago. Do they still require new residential in Illinois to still be piped? Anyone know?

I have never in any house my electrical contracting company has wired or any home my custom home company has built, had a customer request or require metal boxes in their new home. I agree with Norcal, 4 square metal boxes with plaster / mud rings are the best.

Personally if I ever get a chance to build my dream home, my house will be piped and BX cabled, thus requiring metal boxes.

 

[v7guy]

I did a gut job on my house. I used plastic boxes extensively.

anything more than a 2 gang outlet I wish I had used metal, there is some give. With switches, even the 4 gang is fine.

next time I do it the home will get plastic for all the switches regardless of the number of switches. the outlets will only get plastic if they are single, the double will probably be fine, anything over two outlets will always get metal.
In the garage I would use metal in every outlet that's not a single as I tend to use them extensively.

this is just my opinion from my experiences after a year.

 

[MrMark]

I like 4S or 5S boxes with rings for pretty much everything. My house is a mix of flex and romex and the only place I used plastic boxes was for triplex switch boxes and single outlets. I don't like how the plastic move in and out. With the triple box I feel that is the cut off where you need support on two sides.

For remodel I like the new smart boxes which are plastic. I hate metal remodel boxes. The main thing for me is to get the biggest box within reason.

 

[pentavolvo]

I've never built a house that didn't have plastic boxes; nor have I seen a custom or tract home built in Colorado, Arizona, Ohio, Florida, California, and Hawaii (all states I have family or friends) newer then 25 years that had metal boxes; I know of no electrician including myself that use them (metal boxes) in new residential construction. One of the only places that requires metal boxes is because they require conduit in residential, is in and around Chicago. Do they still require new residential in Illinois to still be piped? Anyone know?

I have never in any house my electrical contracting company has wired or any home my custom home company has built, had a customer request or require metal boxes in their new home. I agree with Norcal, 4 square metal boxes with plaster / mud rings are the best.

Personally if I ever get a chance to build my dream home, my house will be piped and BX cabled, thus requiring metal boxes.

certain countys require conduit in IL still including chicago area

 

[kbs2244]

Cook County (the county Chicago is in) is an EMT code.

 

[ishiboo]

I greatly dislike plastic boxes. In my building, I have had several where the screws that held outlets in place had stripped out the threads in the plastic. I was able to fix them, but I never had that problem with metal.

Coach

I've never had this with the cheap-o wall boxes, however I did just run into just the opposite of this with the heavy-duty PVC boxes used for pvc conduit.

I installed 20 of them on the 1st floor of the barn, to install temporary fluorescent lights. Out of the 20, 4 of the outlets I installed had their hold down screws snap off in the PVC boxes. If I had a bunch of circuits ran in the conduit, this would have been a major pain in the *** to fix. Fortunately it is just temporary fluorescent, and to save time/$$ I cheated and ran a piece of 14-2 NM in it. (Yes, not code - but it's one 14-2 in 1 1/4" conduit, it'll be FINE)

For the most part, I always use plastic for walls/etc protected by sheetrock. For surface mount, either PVC or metal. I've never had an issue with the plastic boxes I've installed, though I've seen lots of issues when they are not properly secured to the stud.

 

[Teken]

Is the PVC style box's close to the price point as a metal device box?

 

[cowboyjosh]

whenever the threads in the plastic strip on the Carlon type boxes we always use a 2 inch or smaller drywall screw to then hold the device to the box, its perfectly legal and does the trick, but ya'll probably already knew this trick of the trade.

 

[kb2tha]

Is there any instance where you can not use these box's in a residential install? I live in a very cold area in Canada so would they be alright to be installed outside?

Specialty boxes for ceiling fans are metal. I do not know of any plastic box that would do the same as the metal fan box is designed for.
Ken

 

[ishiboo]

whenever the threads in the plastic strip on the Carlon type boxes we always use a 2 inch or smaller drywall screw to then hold the device to the box, its perfectly legal and does the trick, but ya'll probably already knew this trick of the trade.

That sounds like a great issue to have...

My hold-down screws snapped off flush with the box

 

[mrb]

Specialty boxes for ceiling fans are metal. I do not know of any plastic box that would do the same as the metal fan box is designed for.
Ken

there are plastic fan / heavy fixture boxes that straddle a joist allowing long wood screws to go directly into wood. They work quite well. Arlington FB423 is one. They have other types as well.

 

[mrb]

Is the PVC style box's close to the price point as a metal device box?

considerably cheaper, at least here in the US

 

[Charles (in GA)]

Fortunately it is just temporary fluorescent, and to save time/$$ I cheated and ran a piece of 14-2 NM in it. (Yes, not code - but it's one 14-2 in 1 1/4" conduit, it'll be FINE).

Nobodys saying anything because there is nothing wrong with running "Romex" in conduit. You still have to meet fill requirements based on notes per Chapter 9 of the NEC, but it would not be anywhere close with 1-1/4" conduit.

Charles

 

[Norcal]

whenever the threads in the plastic strip on the Carlon type boxes we always use a 2 inch or smaller drywall screw to then hold the device to the box, its perfectly legal and does the trick, but ya'll probably already knew this trick of the trade.

My method of repairing stripped plastic boxes is to use a Heli-Coil kit, works great & you get to use the proper device screws. Allied Molded fiberglass boxes are known for shearing off 6/32 screws.

 

[Norcal]

whenever the threads in the plastic strip on the Carlon type boxes we always use a 2 inch or smaller drywall screw to then hold the device to the box, its perfectly legal and does the trick, but ya'll probably already knew this trick of the trade.

My method of repairing stripped plastic boxes is to use a Heli-Coil kit, works great & you get to use the proper device screws. Allied Molded fiberglass boxes are known for shearing off 6/32 screws, Slater "Quik-Clik" are another POS box that I refuse to use & curse whoever does....

 

[79firebird]

most people i know use the plastic ones. There are ones for the outer walls that have foam on them that seal when the wire goes into them and seals around the edges for the drywall. when i was in Alberta i saw them in a lot of newer homes.

 

[sneezer41]

You also must ground a metal box, and IIRC the strain relief counts against conductor count, so you can have that issue

 

[Rosco]

I did a gut job on my house. I used plastic boxes extensively.

anything more than a 2 gang outlet I wish I had used metal, there is some give. With switches, even the 4 gang is fine.

next time I do it the home will get plastic for all the switches regardless of the number of switches. the outlets will only get plastic if they are single, the double will probably be fine, anything over two outlets will always get metal.
In the garage I would use metal in every outlet that's not a single as I tend to use them extensively.

this is just my opinion from my experiences after a year.

I just screw a 12" long piece of 2X4 to the plastic box on the opposite side of the stud it is mounted to. Once sheetrock or any wallcovering is installed, one screw in the 2X4 block and a plastic 3 or 4-gang is going nowhere.

 

[Charles (in GA)]

I just screw a 12" long piece of 2X4 to the plastic box on the opposite side of the stud it is mounted to. Once sheetrock or any wallcovering is installed, one screw in the 2X4 block and a plastic 3 or 4-gang is going nowhere.

Hope you are not running the screws thru from inside the box, that is a code violation on non-metallic boxes. NEC 314.43

Charles

 

[Grogan14]

Hope you are not running the screws thru from inside the box, that is a code violation on non-metallic boxes. NEC 314.43

 

[walrus]

Why the rolleyes? what he said is true and he even quoted the code

 

[Teken]

Why the rolleyes? what he said is true and he even quoted the code

Can you clarify why this is wrong? Maybe I need to see it visually to know why it is wrong.

Do you mean if ANY metal screw is inserted into the plastic device box this is a no no?

Or are we talking about someone being stupid and putting a screw from the back side entering the box?

 

[mrb]

Hope you are not running the screws thru from inside the box, that is a code violation on non-metallic boxes. NEC 314.43

Charles

can you explain further? I was thinking it is ok to put a screw in the recessed dimple in the back of the box.

 

[Teken]

can you explain further? I was thinking it is ok to put a screw in the recessed dimple in the back of the box.

I also would like to know and have clarification on this too. I don't understand what would be the problem with that to be honest?

If you have a metal box, its screwed or nailed down, and the box is also grounded. With a plastic box there is no need to ground the box as its plastic etc.

Plus, the screw going into the wood would not transfer any voltage else where.

 

[Charles (in GA)]

Don't know what else to say, sometimes, on the surface, the code doesn't seem to make sense, but USUALLY, but not always, there is some good underlying reason. All I can do is quote what they say.

Charles

NEC 314.43 Nonmetallic Boxes. Provisions for supports or other mounting means for nonmetallic boxes shall be ouside of the box, or the box shall be constructed so as to prevent contact between the conductors in the box and the supporting screws.

 

[MrMark]

The issue with the screws is not grounding it is chaffing. You can't install screws in places the box wasn't designed to accomodate. The section Charles quoted is why the smart boxes have protection for the screws that are driven internal to the box. I personally would never put a screw through the inside of a plastic box.