mystery switch

[ken hug]

i have a switch on the right side of mycharger transformer in my swift royal470 made in 2003,it is small and round with 1/0 on it it is wired to the charger but what it does is unknown anybody come across this before

 

[RogerL]

It may switch the charger off.

 

[ken hug]

that was my thought,i asked the man who serviced my caravan,and he said he didnt know i was the second person to ask him.thanks