I'm used to making sure electrical wire is setback 1 1/4 inch from the face of a wood stud, but what are the requirements (US NEC) for 2 1/2 inch steel studs? They appear to come punched out for wires or plumbing, but wouldn't provide enough setback to protect the wiring. The steel stud is designed for a screw to go through it. Are there thicker steel protection plates designed for steels studs, or would that even be necessary?
The NEC language for metal studs is different, it doesn't actually say 1.25", but enforced much the same.
300.4(B) Nonmetallic-Sheathed Cables and Electrical Nonmetallic Tubing Through Metal Framing Members.
(1) Nonmetallic-Sheathed Cable. In both exposed and concealed locations where nonmetallic-sheathed cables pass through either factory- or field-punched, cut, or drilled slots or holes in metal members, the cable shall be protected by listed bushings or listed grommets covering all metal edges that are securely fastened in the opening prior to installation of the cable.
(2) Nonmetallic-Sheathed Cable and Electrical Nonmetallic Tubing. Where nails or screws are likely to penetrate nonmetallic-sheathed cable or electrical nonmetallic tubing, a steel sleeve, steel plate, or steel clip not less than 1.6 mm (1∕16 in.) in thickness shall be used to protect the cable or tubing. Exception: A listed and marked steel plate less than 1.6 mm (1∕16 in.) thick that provides equal or better protection against nail or screw penetration shall be permitted.
Sometimes you can drill an extra 1/4" hole to use a zip-tie to pull the cable against one edge to require just one plate or zip-tie toward concrete wall if stud if stud is just furring.
The wording of the previous paragraph that covers wood leaves no wiggle room to not use nail plates on edges not likely to get nailed or screwed to like double walls or furring.