I had a handyman (licensed for "simple" electrical work, but not master electrician) hang 3 new ceiling light fixtures and install dimmer switches on 2 of them (a 5-bulb and a 2-bulb). Each of the fixtures is rated for 100w incandescent bulbs, which I used. However, the dimmer switches get hot at full power and lower power. I replaced the 100w bulbs with 75w bulbs. Same problem. Any suggestions?