I assume you mean, that it give you a shock when you turn it off, DO you get the shock as you touch the switch, or when you operate it. The switch shorts the spark voltage to earth, i.e the frame when switched. If you are getting a shock after switching, I would think loose connection on the earthing of switch, check connections. Shock as you touch it, would suggest contamination of switch, so it is connecting to you, clean switch.
SD, July 2011
