Safest way to make a high-voltage switch
You could use a slide switch such as "Arcoelectric" (great name- dealt with a Taiwan company called "Sure Fire Electric" for some stuff, but I digress..) screwdriver-slot-switched K22208EB DPDT, UL CSA rated at 300VAC (424V peak) 4A. It does not have a DC rating but since it will never be switched under load.. it might be okay depending on your regulatory requirements. 

These are of the same ilk as the voltage selector switches used to switch the capacitor doublers in PC power supplies.