Twidec 2 Pieces Oscillating Switch 6 Pin 3 Position On Off Ac 10A 125V 6A 250V Dpdt Car Boat Black Kcd4 Oscillating Switch Kcd2-203 Black

Q: Will the led light if the switch is used for a 12vdc circuit?

Light only connect to AC 110 -125V,Can light up

Q: what size is the switch?

Mounting Size: 26 x 21.5mm / 1.02" x 0.85" (L*W); Overall Size: 30 x 25 x 35mm / 1.2" x 1" x 1.4" (L*W*H)

Q: Can this be used as a transfer switch where a single load (i.e. furnace) can be switched between 2 power sources such as a generator and line power?

This is no where near the wattage rating you would need for such an application. Most furnaces are in the KILOWATT range. This switch is only 10 amp, 120 volt switch or 6 amp 240v switch. Most furnaces I have seen are 240v hardlined. I suspect the load for a furnace will be higher than the 1200 Watt max this switch can hold (unless just a controller for a gas furnace). It is a fire hazard if more wattage is going through this rocker and is not to code for such a practice. I would look for a higher rated one. Also, there are dedicated switches for that that are better suited - especially as once the power grid is energized you will want to make sure the generator and the grid are isolated and this little rocker is no where as powerful as needed. All in all, no. Get a better, higher rated switch.