I’ve never worked with the blue plastic receptacle boxes before. I’ve always used metal in the past. I’m in a situation where I need to wire the outlets on a circuit in an addition for a family member. They have nailed the blue boxes to the studs, and run the romex to all these boxes. They punched the holes out of the blue boxes. The wire is really loose, since there are no clamps in these boxes. These punch-out holes seem pretty big to me. Do they make clamps that fit the holes? Or don’t you need clamps with the blue plastic boxes? Is the staple fastener near the box all you need?
Thanks.
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I've used those plastic boxes alot. Really, I don't think you're supposed to punch the tabs out entirely, just pull-push the romex through and leave the tab there to prevent the cable from being pulled back out. Sometimes if you screw up, those tabs either get pretty loose or seperate entirely. My inspector has always passed those, as long as I made sure the wire was stapled to a stud within 8" of the box. I always try for less than 8", though.
Oops. I guess they shouldn't have popped those tabs all the way out. Live and learn.
Thanks for the info.
Depends on the style. Some have rectangular tabs that you just punch open, and they spring back to (supposedly) hold the wire. Others have a round opening for which there is a pop-in plastic deal that is sort of a one-way valve for wire.
In theory you don't need a box clamp if you staple within so many inches (4? 6?) of the box.
Glatt,
Per Code, a single-gang plastic box for NM cable need not have a cable clamp. If you're working with the blue Carlon boxes, the most common brand in my area, the single-gang boxes have four knockouts, one in each corner. Those pop completely out, and are of no use as a clamp.
Some other brands of SG plastic box have some sort of cable clamp. I think it's Arlington fiberglass boxes that have a plastic insert that makes the cable bend sharply as it enters the box, and secures it after a fashion.
For two-gang and bigger boxes, cable clamps are required. On Carlons and some others, the clamps are plastic tabs that you push the cable past as it goes into the box, that then spring back and grab the cable (sometimes). A lot of guys break those clamps off because they are a PITA, but in that case an inspector would have every right to red-tag the job.
Code calls for securing NM cable within 8" of where it enters the box if there is no clamp, and within 12" where a box clamp is used.
And yea, a holes in the SG boxes is big, if you have a 14/2 running through it. But it's O.K., because it's the cable staple (or clip or whatever) that keeps the cable from falling back into the wall.
Work safe,
Cliff