I replaced an older switch yesterday on an existing line of recessed lights. There are five lights on the one switch. On the same breaker; but different switch, there are 7 more recessed lights (all in a basement, in the process of being renovated, and easily accessible; also both lines are missing one bulb, so they are not pulling a full load). On the same breaker there is also an outlet that runs a dehumidifier. This has been the setup for over a year when the project started.
If it is an overload on the breaker it has never been an issue before. Yesterday I switched out an older switch that was very noisy when flipped, for a newer, quieter switch (not new, but pulled from another spot in the house). The major difference is that the newer switch had a ground and and the older switch did not.
When I came home tonight and flipped the switch I heard a noise and the breaker tripped (not the noise of the breaker tripping, an additional electrical noise, like a surge). The dehumidifier was also on when I turned the switch on. I reset the breaker and did it again, tripped again. I had this on for hours yesterday (though I think the dehumidifier went on after the lights were on). When I turn on the line with the 7 lights nothing trips. It only happens on the new switch. Can the ground be messing it up (or rather be pointing to a problem that I didn't know was there)?