Can't add much to what the pro's have already said.............except to say.......similar event happened at a house around corner from where our first home was. Same type of situation......some remodel work was down........and shortly after that the house burned to the ground.

The cause they came up with was a nail driven into a wall hit a wire.........and the short it created made the nail hot enough it ignited the pine board it was driven into. Apparently the breaker didn't see that level of short as a problem........just a load on the line. If a dimmer switch was melted, same condition may still exist. If it does, I'd want to be finding it at whatever the cost.

My old Electrical Code instructor had a problem with an arc fault breaker constantly tripping in the garage he just built. He went over and above with the arc faults, he doesn’t need them in a detached garage.
Tried a new one, same thing.. He pulled some sheets off and found a bunch of long staples from the crew that sheeted the outside, one bit through his 14/2 circuit. Guess they used up the long staples that were in the gun before switching to shorter ones.
Some folks switch to a normal breaker when the arc faults keep tripping, they’ll hold if there’s not enough of a fault……until it burns itself clear and nothing works, or the fire department shows up.
Sometimes when the breaker trips, it’s not weak or faulty, it’s actually doing its job……lol

Seen guys that will replace a breaker instead of hunting the cause of breaker tripping.

Might do better to just abandon the old wire and run new.

I got to do some trouble shooting today. I pulled the dimmer switch and put in a regular toggle switch. There are (3) sets of wires coming from above. I hooked up each set of wires individually to the toggle switch. Sets A and B did nothing. Set C tripped the breaker as soon as the switch was toggled.




I tried pulling the cans. I could only get the outside cover pulled. I found the junction box inside. It's all so tight.



It's looking like running a new wire is going to be easiest, but i doubt thats going to be very easy. Tomorrow I plan to get in the small attic area and see what it looks like from above. Luckily I've got an uncle who understands wiring and wants to help. I saw him today at a family get together. I'm going to call the electric company Monday and express my disappointments with their performance.

Built a house in 85 that had can lights in kitchen and dinning areas. This was before LED bulbs. The dimmer switch got very hot. Had to change to a dimmer that was rated for more amps. Seem to remember the bulbs drew 175 watts each.

Probably would not have been a problem with today’s LED bulbs.