Provided I use a box large enough to meet the fill requirements (and use 10 AWG conductors), are there any additional requirements I should be aware of when installing a new 240v 30 amp receptacle for a clothes dryer?
More specifically, does the box need to be metal or have certain attributes that a standard blue plastic box might not have? Is a cable clamp required?
My state (CA) currently adopts the 2011 edition of the NEC. I haven't had much luck finding anything that specifically addresses this so far.
Best Answer
Be sure you use a 30A double-pole breaker to adequately protect your wiring. Make sure you provide an equipment ground and use a NEMA 14-30 receptacle.
The box can be metal or plastic. Some form of cable clamp is always required, it's just that most plastic boxes have an integrated clamp (that finger-trap style door).
If using NM cable, The cable must be supported and secured by staples, cable ties, straps, hangers, or similar ļ¬ttings designed and installed so as not to damage the cable, within 300 mm (12 in.) of the outlet box. If the wire is being fished through a finished wall and the wire cannot be secured in such a manner, this rule does not apply.
Pure Opinion
As far as selecting an actual box, from experience, I recommend getting a 2-gang plastic box (or something equivalent in size if you want to use metal). The larger the capacity the better because a NEMA 14-30 receptacle with four #10 wires is not only bulky, but can be a very stiff pain to manipulate. They even make boxes that are "specially" designed for this purpose.
If you use a 2-gang box, you'll want to get a faceplate that is designed to match (faceplates for NEMA 14-30 receptacles are also manufactured for 1-gang boxes).