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

 

[Leesparkykent]

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

Sound like a rubbish plan.

 

[Daljit68]

Sound like a rubbish plan.

Why would that be?

 

[Spoon]

Do you not think it would be a good idea to isolate the 'switch live' and 'neutral' as well?

 

[Charlie_]

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

 

[mhar]

You need to check the instructions for this new fan, a lot require a 3 Amp fuse fitting

 

[telectrix]

or give this guy a job.

 

[Wilko]

Hi - just so you know - new regulations from January mean that changing the wiring on a circuit with lights will require an RCD be fitted, if it’s not already. And depending on details, a building works notification (Part P) might also be required as you are doing electrical work in a bathroom. An Electrician can help you with both of these aspects, as well as testing the completed works are safe, just saying .

 

[HappyHippyDad]

That really doesn't sound good at all Daljit, also dangerous because:

1. You could be taking the permanent live (PL) from a different circuit.
2. You will only be isolating the PL not the switch live, so if you do use the isolator switch (i use the term lightly) you would still have a live fan when the light switch was on. Someone who moves in after you could well get an electric shock as they would never suspect that it had been wired so badly.

I realise you are probably trying to safe some money but you really should get an electrician to do this work.

 

[Daljit68]

Hi - just so you know - new regulations from January mean that changing the wiring on a circuit with lights will require an RCD be fitted, if it’s not already. And depending on details, a building works notification (Part P) might also be required as you are doing electrical work in a bathroom. An Electrician can help you with both of these aspects, as well as testing the completed works are safe, just saying .

Hi, WC so no special regs

 

[Daljit68]

Do you not think it would be a good idea to isolate the 'switch live' and 'neutral' as well?

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

 

[Daljit68]

That really doesn't sound good at all Daljit, also dangerous because:

1. You could be taking the permanent live (PL) from a different circuit.
2. You will only be isolating the PL not the switch live, so if you do use the isolator switch (i use the term lightly) you would still have a live fan when the light switch was on. Someone who moves in after you could well get an electric shock as they would never suspect that it had been wired so badly.

I realise you are probably trying to safe some money but you really should get an electrician to do this work.

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.

 

[Daljit68]

Hi - just so you know - new regulations from January mean that changing the wiring on a circuit with lights will require an RCD be fitted, if it’s not already. And depending on details, a building works notification (Part P) might also be required as you are doing electrical work in a bathroom. An Electrician can help you with both of these aspects, as well as testing the completed works are safe, just saying .

It’s a WC

 

[Charlie_]

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

I thought you also wanted it to work whilst the light was off?

 

[Daljit68]

or give this guy a job.
View attachment 49903

Couldn’t do worse than a scouser in my experience

 

[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?