Triple pole shower isolator wiring

[JACKC]

Just looked at a friends 1st fix shower installation as asked to finish off as electrician keeps failing to turn up to finish, building regs informed to cover me. Sussed out all other circuits for utility room and wall lights but no experience on this circuit.
basically 1.5mm twin and earth to hole in ceiling for extractor fan and 3 core and earth from same hole to box in wall which I assume is isolator. What is the circuit for this switch please.
Any help or pointers in right direction are greatfully received.

 

[C&GStudent]

Preparing to get shot down...

Are you sure the hole in ceiling is not the light? The 3c+e then goes to the isolator, then should go on to fan.

Is there only one 3c+e in the box?

 

[JACKC]

the fan is a combined light and extractor

 

[ban-all-sheds]

Does the fan part have a timed overrun?

What you have described in terms of cabling won't work - with only one cable going to the isolator, how can it isolate anything? And what will it do with respect to the other cable going to the light?

Was the guy who started this job really an electrician, or was it your friend?

And did you really inform the council, and pay their fee? What did they say about what you plan to do?

 

[JACKC]

Yes he was a part P electrician who carried out initial installation, I'm going back up to have a look at circuit again as it sounds like I have described it wrong, also will check extractor, will post back with new info, Thanks for help so far.

 

[Steve]

So, no, he hasn't paid their fee

 

[ban-all-sheds]

He was a bit of a silly-billy to inform them then, wasn't he, boys and girls?