Extractor Fan

[Mr T]

Hi

I have a question about wiring a bathroom extractor fan that is to be turned on and off by a PIR

Here is what I have I would just like some clarification on the wiring

So from the Spur I have my ring cables so they connect into the supply side of the spur

I then need to connect from the Load Side of the Spur to the PIR - The PIR has a SL-L-N and Earth connections , so is it Line from the load to line on the PIR , N from the Load to N on the PIR and the same with E ?

I then need a switched live to take from the PIR to the fan , so here is my bit of confusion , if a 3 core and Earth cable is required from the supply side of the spur where would I connect my spare cable at the supply , Im aware all 4 terminals on the PIR would be in use but what about back at the Spur ?

Thanks in advance ?

Stephen

 

[revjames]

there would only be L and N at the spur, you will need a switch wire either from the switch or the fitting depending on which is easiest. You can get an isolator switch that has L, L1, and N (L1 = switched)

 

[spinlondon]

You don't need 3 core from the FCU.

You need a switched live from the PIR to the fan, to tell the fan to operate. You then obviously need a permanent live to the fan, a neutral and an earth. You can take these from just about anywhere, the FCU or the PIR. You could run direct in T&E from the FCU to the fan, then with a JB near the PIR, run T&E to the PIR and from the PIR, a single to the fan for the switched live.

Or you could run T&E to the fan, and 3C&E to the PIR.

Or T&E to the PIR, and then 3C&E to the fan.

I don't know where the PIR, fan and the spur are being positioned?

 

[revjames]

better taking a bathroom fan from lighting circuit than a spur in any case. Are you doing this job for yourself ie at your own property?

 

[Mr T]

You don't need 3 core from the FCU.You need a switched live from the PIR to the fan, to tell the fan to operate. You then obviously need a permanent live to the fan, a neutral and an earth. You can take these from just about anywhere, the FCU or the PIR. You could run direct in T&E from the FCU to the fan, then with a JB near the PIR, run T&E to the PIR and from the PIR, a single to the fan for the switched live.

Or you could run T&E to the fan, and 3C&E to the PIR.

Or T&E to the PIR, and then 3C&E to the fan.

I don't know where the PIR, fan and the spur are being positioned?

The Spur is to be mounted above a suspended ceiling , the fan is already in place , the PIR will be near the entrance to the door..

So am I right in saying it would be twin&e to the PIR so Live from the Load to Live on the PIR and N from the Load to N on the PIR then take 3 core from the PIR to the Fan i.e. SL on the PIR to L on the fan ?? If the Fan doesnt have a timed overun then am I right in saying you dont need 3 core ??

 

[batty]

Generally pir will control how long fan stays on for so you do not need timer fan all wired in tw/e.

 

[spinlondon]

Yes Mr T, that's about it.

 

[Mr T]

Hi just just thought Id post back some feedback in reference to the above

I connected these Extractor fans today and our wiring method was

From the Spur I ran a 2core&e flex to the fan brown to SL and blue to N and then a 3 core&e flex from the Spur to the PIR..

At the SPUR we connector blocked the brown from the 2core&e flex with the black from the 3core&e flex , the 2 blues were connected to N and the Brown from the 3core&e connected to L

I understand we wired this way to ensure there was only 1 cable going to the PIR due to them being a sod to wire into...

(So at the PIR we have the 3core&e flex ,firstly black (which is linked to the brown that goes to the fan & brown (which is in L at the spur) and finally grey , so am I right in saying that the brown will connect to L at the PIR as this is a permanent live from the Spur and then the black will be the switched Live as this is the cable linked through to the fan ?

 

[spinlondon]

Sounds like it will work, as long as the fan will work withoit a permenant live. May have to link that with the S/L.

Might have problems with the fan switching off while someone's in the bath.

 

[Mr T]

Sounds like it will work, as long as the fan will work withoit a permenant live. May have to link that with the S/L.Might have problems with the fan switching off while someone's in the bath.

I linked out the L and the SL at the fan

 

[sanny]

I hope you identified the black and the grey with the appropiate coloured sleeving : O)

 

[Mr T]

I hope you identified the black and the grey with the appropiate coloured sleeving : O)

Yes