want to Understand Fan Wiring

[ste3g]

I have a new ceiling bathroom extractor fan which has 2 terminals. blue & Black. The house supply cable in the loft has 4 wires. Earth, brown, black and grey ( switched live presumably )

The light switch controls the fan and there is an isolator switch higher up on the wall.

Please can someone explain the wiring diagram because I wan’t to understand the circuit.
Many thanks.

( see attached pix )

 

[ProDave]

Convention is grey= neutral, brown= permanent live and black = switched L, but there are variations so you would normally check to confirm that.

In that case brown and E you safely terminate as they are not used. Black to the fan blue, and grey to the fan black

What's the red and black crimped together?