My husband and I replaced the chandelier in our dining room two nights ago and also added a dimmer switch. The dimmer switch is rated for 600 watts and we only have five 40 watt bulbs in the fixture. This evening while the fixture was on, there was a loud popping sound and then the fixture went out. It isn't any of the bulbs and it seemed like the sound came from the wall. We think it's something with the switch. We checked the breaker and it was not tripped. All other fixtures on the same circuit are fine. The only thing that my husband could think of is that the switch was not grounded. The switch has a ground wire, but the plastic box did not have copper wire to connect to in it. There are twisted ground wires running through the box that my husband is going to connect another wire to and then twist that with the ground on a new dimmer switch. Does this make sense? Could the fact that the switch is not grounded cause this "blowout"? Any suggestions? Thanks in advance.

Even though the dimmer should be grounded, this should not have caused the popping you heard, sounds like just a new defective dimmer.

One thing the new dimmers require, this will be listed in the instructions, is that the power must be OFF to that circuit before connecting the dimmer.