UK Extractor Fan (red and black wires only)

raggaroo · Jul 18, 2021

Hi,

I'm updating our bathroom and I'm changing our extractor fan from a simple ceiling mounted one to a more powerful inline version (Blauberg) mounted in the loft.

The fan only had 2 wires - a black and a red.
It has an isolator switch outside the door in a twin switch plate shared with the lighting. (so 2 switches - the left for the fan and the right for the lights).
There is no timer on the current fan.

We are happy for the new fan to run in the same way - i.e. when the switch is on

The new fan however has 3 connections - Neutral (N), Live (L), Switched Live (LT).

I wired up as:
black to N (from the isolator switch this comes from a blue wire)
red to L (again its red to red in the isolator switch).

The fan doesn't work.

I attached photos of the twin switchplate with the isolator switch (on the left) and the top of the fan.

You see that the red and black cables I mentioned are 2 core
There is then a 3 core + earth running up from the same switch plate to the lighting to the ceiling rose which is now in the loft and accessible.

Can anyone help?

Many thanks,

Chris

littlespark · Jul 18, 2021

We can only guess here what is the feed to the switch, so someone with a voltage tester would have to clarify….

the 3 terminals in the fan are neutral…. Permanent live, which actually runs the fan and a switched live, this is normally joined to the light so the fan operates when the light goes on, and the permanent live runs on after the light is turned off.
It appears you have a live, switched live and neutral at this switch.
you may also have the same at the light….

westward10 · Jul 18, 2021

Put a link between L and L1.

sinewove · Jul 18, 2021

raggaroo said:
Hi,

I'm updating our bathroom and I'm changing our extractor fan from a simple ceiling mounted one to a more powerful inline version (Blauberg) mounted in the loft.

The fan only had 2 wires - a black and a red.
It has an isolator switch outside the door in a twin switch plate shared with the lighting. (so 2 switches - the left for the fan and the right for the lights).
There is no timer on the current fan.

We are happy for the new fan to run in the same way - i.e. when the switch is on

The new fan however has 3 connections - Neutral (N), Live (L), Switched Live (LT).

I wired up as:
black to N (from the isolator switch this comes from a blue wire)
red to L (again its red to red in the isolator switch).

The fan doesn't work.

I attached photos of the twin switchplate with the isolator switch (on the left) and the top of the fan.

You see that the red and black cables I mentioned are 2 core

There is then a 3 core + earth running up from the same switch plate to the lighting to the ceiling rose which is now in the loft and accessible.

Can anyone help?

Many thanks,

Chris