Extractor fan to timer type

[Daljit68]

Hi

I’m thinking of changing an extractor fan (in a WC) to one with a run on/timer. The current set up doesn’t have an isolator, and wiring runs from the light bulb to the fan, which is sited in the ceiling about 18” away. The fan is vented through a flat roof above.

Now, I realise that i’ll need a permanent live and to fit an isolator switch. I’m thinking of doing this:
- to leave existing wiring as is, and take a live feed from a lighting circuit junction box in the attic;
- to install an isolator switch in the permanent feed run, ie in the attic.

I’d rather not have to channel into walls to run a new 3 core cable.

Thanks

 

[Daljit68]

The fan is in a flat roof.
You are going to take a feed to it from the attic?

You never seen hooses with pitched roofs to the front and flat at the back???

 

[Charlie_]

Couldn’t do worse than a scouser in my experience

The guy in the picture could well be a scouser

 

[Charlie_]

You never seen hooses with pitched roofs to the front and flat at the back???

So you are planning on taking a feed from the pitched roof at the front round to the flat roof at the back?

 

[Charlie_]

I would just change the light fitting to a sensor type.. pir or mw

 

[Spoon]

Surely anyone looking to service the fan will know it only operates when the light is switched on...

I’m thinking of changing an extractor fan (in a WC) to one with a run on/timer.

Hi mate. The fan will require a 'permanent live' as well as a 'switch live'. Both will need isolation, as well as the 'neutral'.
Have a look at the manual for the fan you are thinking of getting. This should tell you how to wired it.
What fan are you thinking of getting?

 

[Tony Reidy]

Thanks for considered comment! It’s less about saving cash, it is a simple job but just don’t like the idea of channelling into walls.

Why do you need to channel into the wall if all the wiring is in the flat roof

 

[Daljit68]

Hi mate. The fan will require a 'permanent live' as well as a 'switch live'. Both will need isolation, as well as the 'neutral'.
Have a look at the manual for the fan you are thinking of getting. This should tell you how to wired it.
What fan are you thinking of getting?

An Envirovent SilentT 100.

Now thinking I could run wires from lightbulb (which run direct to CU (in WC) via switch) and a permanent live from lightning circuit in attic to an isolator switch located in ceiling, adjacent to fan.

 

[telectrix]

Couldn’t do worse than a scouser in my experience

these are real fans.

better than bloody bagpipes

 

[Spoon]

As @Tony Reidy asked above, "Why do you need to channel into the wall if all the wiring is in the flat roof "??

 

[Wilko]

An Envirovent SilentT 100.

These fans are ok, got one in my bathroom .

 

[Daljit68]

As @Tony Reidy asked above, "Why do you need to channel into the wall if all the wiring is in the flat roof "??

Single wire runs to switch in WC then up wall into flat roof void, then out at light socket. Linked from there to existing (non-timer) fan.

 

[telectrix]

why not just leave the light on for 20 minutes? otherwise it's not essential as in a bathroom extracting steam, only fart gas. leave for the benefit of next user.

 

[Spoon]

Single wire runs to switch in WC then up wall into flat roof void, then out at light socket. Linked from there to existing (non-timer) fan.

So there is a switch live wire going to the switch from the light?
There should be a 'permanent live', 'switch live' & 'neutral' at the light then. Can you not tap of these?
Does your CU have an RCD?

 

[Andy78]

This seems to be following a familiar pattern.
DIYer asks for advice
Forum says no don't do that it would be wrong and possibly dangerous
DIYer says no it won't

From here it usually goes one of two ways. DIYer sees sense and employs the services of an electrician to protect their own safety and that of their family and property.
Or the forum end up being tarred as elitist scum whose trade is a doddle and we are only withholding information as we are rip off merchants.

I'm on the edge of my seat.

 

[telectrix]

This seems to be following a familiar pattern.
DIYer asks for advice
Forum says no don't do that it would be wrong and possibly dangerous
DIYer says no it won't

From here it usually goes one of two ways. DIYer sees sense and employs the services of an electrician to protect their own safety and that of their family and property.
Or the forum end up being tarred as elitist scum whose trade is a doddle and we are only withholding information as we are rip off merchants.

I'm on the edge of my seat.

well, it's only 2 wires 3 wires, 4 wires. oh bugger, it's on fire.