bath fan and light problem

[sm2000]

I have wired bath fan with isolator. it is a timer one. so once the light is on it remains on for few minutes.

It is always keeps on unless i switch off from isolator switch.
Please help. i have enclosed the drawing i used.

please see my album for the image.

 

[PrenticeBoyofDerry]

Recheck your wiring, and make sure you have not got your switch live and live conductors terminated in reverse at fan and at light fitting.
The drawing looks fine, if the problem then continues, you will require to test for voltage, using an approved double pole/probe tester.
Test at fan perm live to neutral or earth, you should get a reading of around 240V, when resting or active. Then test at switch live to neutral/earth, you should get around 240V when switched and around 0V when rested.
Also test across neutral to earth to confirm polarity for 0V reading.
If these readings are confirmed your fan is faulty.
Please be aware if this fan is newly installed (not replacement) and electrical equipment installed within bathroom zones one and two, it is deemed notifiable work and requires building controls notification and either minor works or electrical installation certificate and chased/ buried cable will require to be within permitted routes and depths of chase compliant to part A of building regulations. Also 30mA RCD will be required.

 

[sm2000]

I have checked the wiring seems fine . The fan is good. One thing more to further investigate if I disconnect the commen wire in light switch then fan works properly as it should but then light turns off.

 

[PrenticeBoyofDerry]

You mean bathroom lights do not come on at all?
What type of lights in bathroom, do they have extra low voltage transformers connected to them?
Check the timer setting on the fan is at minimum time and what model of fan is it?
Reconnect switch com and see what happens.

 

[sm2000]

please read my last post in conjuction with first post . I explain here again. I can switch on lights or fan at the same time not both and if I do then only lights turn on not fan. Nothing wrong with fan as I have tried another fan there and other fan works exactly as same. When I join switched live with fan's swtiched live then fan does not turn on however if I remove switched live of light (brown or common wire then fan works fine but not light.

 

[sm2000]

lights are ip44 from b n q and they do not need transformer, nothing wrong with the lights.

 

[sm2000]

Sorry forgot to mention the make of the fan. It is REX fan with timer.