This is more to satisfy my curiosity than anything else.
The bathroom has the light and a 12v extractor fan both activated by the pullswitch by the door. The fan appears to be wired from the ceiling light with a three core and earth. Permanent live, switched live (with a brown sleeve on the core) and neutral (blue sleeve on the core)
As I understand it, the point of having the live and switched live is to allow the fan to overrun on a timer after the light is switched off. Only it doesn't. It seems to go off with the light.
If I can track down the transformer, which is presumably somewhere in the loft, should there be a control or selector switch for a timer overrun?
Also, while I think of it, the downstairs shower room has an identical fan and light, but wired completely differently. There's a light switch on the outside of the door, but also a fan isolator--presumably a three pole switch--and the ceiling light is fed with one twin and earth cable. That fan does overrun.
Why does the downstairs shower need a separate fan isolator switch when the bathrom upstairs doesn't?