Mixing plastic and metal boxes and conduit on same run

[jragain]

I have a 120 volt 12-2 circuit coming into my garage that is not being used. It was run along the ceiling of the garage in emt and presently terminates in a metal box on the ceiling. I want to use this circuit to power a couple of new receptacles on the surface of a concrete wall, then go into a finished wall and put more receptacles inside that wall. Can I use plastic boxes in the finished wall with metal boxes on the concrete wall? How do I handle the grounds on such a run? Thanks in advance for any advice.

 

[Alchymist]

Any metal boxes in the run will have to be grounded. I ran 1" plastic for 2 runs in my garage, both terminated in a metal box. Ground wire was broken out and attached to box. Wouldn't use a metal box in the middle of a plastic run, as it would have to be grounded also. The plastic junction boxes are pretty cheap. I always try to put the receptacle in a metal box, though, and securely grounded. Just more rugged that way.