I’ve been wiring for over 30 years, but never did it through steel studs. I know I have to use bushings to pass wires through holes, and use clamp type supports to fasten near boxes. How are boxes mounted? I’ve seen reference to some sort of crimping device, but can’f find more about that. Are regular strapped boxes used with metal screws? Is is necessary to use steel boxes, or to separately bond the studs to the equipment ground? Any other words of wisdom?
This is all for a basement shop. I plan to run several 20A/120v circuits for small tools, etc., and several 20A/240v. circuits for the heavy machines, including the dust collector. The latter will have outlets in boxes around the space, since I don’t yet know where I want things (and probably will never know; I’ll just have everything on mobile bases and keep moving them around till I’m happy — i.e., forever). I plan to have everything on GFCI’s (240v. included) since this is a basement.
Any thoughts, critiques would be welcomed.
Replies
I'm not an electrician. Electricians who work for me either get me to fasten a piece of two-by-whatever to the steel stud at the box location so they can use a normal box or they use boxes designed for steel studs which have straps which bend around the steel stud. These are also screwed on. Ganged boxes will usually need to have some bridging added between studs.
"This is all for a basement shop. I plan to run several 20A/120v circuits for small tools, etc., and several 20A/240v. circuits for the heavy machines, including the dust collector. The latter will have outlets in boxes around the space, since I don't yet know where I want things (and probably will never know; I'll just have everything on mobile bases and keep moving them around till I'm happy -- i.e., forever). I plan to have everything on GFCI's (240v. included) since this is a basement."
There is no requirement to have 240 circuits on GFCI's. And really only neglitable safety improvement.
All of that equipment will have equipment grounds.
GFCI's are required on 120 circuits becaue they are often used and ABUSED with portable equipment. Ground pins get cut off. Plugs are pulled out the wall by the cords. Tools are lifed by their cords. Cords get cut. Used with extension cords that also get cut, hanked on, stepped on, and run over.
Large 240v equipment is not going to see that kind of abuse. Likewise the code does not require GFCI protection on 120v receptacles that serve stationary appliances such as refigerators, wahsers, and sump pumps. Because they are not portable and won't see the abuse that portable appliances do.
I thought that not having refrigerators and sump pumps on gfci's also dealt with the consequences of a trip, be it false or minor (if there is such) from some other device.
Bob
While it is true that the false trip of GFCI on a refigerator or sump pump can cause lots of harm, the lack of GFCI protection IF IT WAS REALY NEEDED has a much higher risk.
And the code does not mention anything about what damages that there would be if there was a false GFCI trip.
The only requirment is that these be appliances that are not readily moved.
That includes a washer. And other than having dirty clothes there is no harm down if a it was connected to a GFCI and had a false trip.
Agree, the washer looks like it would be the most potential for injury with the least impact of a false. Some believe that since it is hooked to water lines that they have a ground, an error I believe since the solenoid bodies are pretty much insulators unless in the fill mode, even then not a true ground path.