is switches in residential work required to be grounded . I always ground them when i do a installation,but a teacher at work asked was it a "shall" in the trade. he has a new home and was shocked by a 3 way switch it had no ground, he found the problem a loose wire.

Sam,

On the national level, it became a requirement to ground the metal straps of all switches & dimmers, regardless of the occupancy, when the 1999 NEC was adopted. Prior to then, it was not a requirement.

Tom

Yes. Code requires that all plugs, and switches be grounded (Now)for new homes. Grounding is a MUST. If the 3 way switch had no ground, then he should replace the switch with the proper switch.