i have an old still functioning gfci and a metal box right now i have a 16 AWG extinsion cord made out of it. but i'm thinking about putting it on the end of an old 12AWG cord i have been using to power my light, power supply, soldering iron + what ever i may be working on (probly a computer or fixing something then testing it.) would replacing the normal extinsion cord socket with the gfci be a good idea. (i know it is safe but for some reason exposed metal bexes always make me a little nervous.) the cord would be laying on the floor near my work bench. should i just get a plastic box or would that defeat the gfci porpus?