"Jay-T" wrote in message
...
"RBM" wrote in message
...

"Josh" wrote in message
...
I'm adding a couple of steel outlet boxes and switch boxes in my
residence, fed by 12-2 w/g Romex. I've noticed in Lowes some of the
boxes have clamps built inside to secure the Romex, and some don't.
Are clamps required by NEC?

The other thing I'm wondering about is the knockout holes on the sides
and back of the boxes. Are rubber grommets required for the holes I
run the Romex through?


Depending upon the box type and composition, clamps or connectors may or
may not be required. For metal boxes, I'm a big fan of the Arlington
button. They take up very little space and are easy to use. Be sure to
use boxes of adequate size for the size and amount of cables you plan to
use in each box.

I am curious...., why don't plastic boxes come with round knock-outs like
metal boxes have?

Instead of having to deal with the blue plastic bendable flaps, I would
much rather have a plastic box with round knock-out holes, and then use
Arlington buttons to secure the incoming wires.

You can get larger plastic boxes, like 4" square with knockouts, but I've
never seen them on single gang boxes. I'm not real sure that a button will
hold tight in a plastic box. It may be slightly thicker than steel