In article , "John A. Weeks III" wrote:

Are the plastic "legal" per building codes these days ? Allover ?

Yes, for household use. I don't know for sure about everywhere, but
they are in the midwest.

Not necessarily everywhere in the Midwest -- don't know for sure, but I'll bet
they're *not* legal in Chicago, which has unbelievably restrictive electrical
codes.

Or, does it depend on the local state building code (I live in Mass.) ?

It depends *entirely* on the local electrical code. This may be applied at the
state, county, township, or city/town level. Start at the city/town level and
work up the chain: it's entirely possible that there is a statewide code
which permits plastic boxes, but the city or town you live in has adopted a
more restrictive local code which prohibits them. The only way to know is to
talk to your *local* code enforcement authorities.