Safe to mix wire gauges when installing dimmer switch?
The wire that comes on the switch / dimmer is UL listed for use on 15 &amp; 20 amp circuits. They have a wattage limit many around 600W for incandescent / halogen type lights and 150W for the led type this is the limiting factor with dimmers put two many lights on the dimmer and they get hot and usually will shutdown if they don't have thermal limiterss the electronics in the switch fail before the wire is damaged so you are ok in this case joining the smaller factory installed wires from the switch to your 12 AWG wire.