Hello! I am in the process of wiring for a woodshop in my basement. Several of my tools run on either 240 or 120 volts. I ran 100A service down there to a subpanel (using 2/2/2 wire) and ran two preliminary 20A circuits. One of these is only about 5' long and was run using 12/2 wire. The other was about 30' long and was run using 10/2 wire, just for future unknowns. Each circuit has a dedicated 20A receptacle. I attached a 60W shop light to the 5' run circuit and plugged in my radial arm saw (rated at 11A at 120V) to the other circuit's receptacle. I was suprised to see the light dim (albeit very, very briefly) when the saw was turned on. The house is served by 200A service. Probably less than 10 amps were separately flowing through the main panel when I did this test.
I didn't check, but it seems reasonable that both the light circuit and the saw circuit are sharing the same 120V feed. Regardless, should I be looking at migrating my jointer, saw, planer, and air compressor to the 240 volts that they can run on? Outside of the voltage drop that obviously occurred when I flipped on the saw, am I shortening the life of my tools as a function of this condition?