If you can find one listed for that use, but if you are thinking regular plastic duplex cover plate I doubt you will find a listed one. Carlon round plastic floor boxes have listed plastic covers for receptacle outlets but the listed plastic covers are round, resemble the brass ones, except they do not have hinged snap covers for the receptacle openings like the brass ones do. You unscrew and remove the opening cover, which is why I use the brass ones.
