Despite being a virtual novice I decided to replace our plastic light switches with metal ones - 2 standard, four dimmers. The first one worked, then the one in the hall blew up after I fitted it! Some of the switches have 2 wires, some three, all red in colour. Now the kitchen lights & the living room don\\\'t work but every thing else does. I\\\'ve put back a plastic switch where the metal one exploded! I\\\'m confused, someone help!