My daughter has just moved into a house and in the bathroom there is an isolator for the fan but i have never seen one wired like this one it is a 45amp DP pull switch with the neutrals joined and the permenant live and the switched live going through the switch permenant live in L switched live through N ,when it is in the on position the neon is on untill the light is turned on and the fan runs the neon then goes out untill the light is switched off then the fan stops and the neon comes back on.Is this some new way that people are isolating fans.