The switch doesn't care what voltage the system runs. However, loose connections are always "hot" connections- - - -looseness produces resistance, and overcoming resistance causes heat. A 6V ignition switch actually has bigger, heavier contacts than a 12V, because it takes twice the current to produce the same wattage as a 12V accessory- - - -"voltage X amperage = Wattage". 6V wiring is always heavier gauge than 12V, also.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!