Fans on lighting circuits

[Timlouth]

Can anyone tell me what the rules are regarding connecting extract fans to lighting circuits.
I was once told it was acceptable in certain situations but can find no reference in the 16th or 17th Edition regulations.

Tim.

 

[chivers67]

It is acceptable to wire in a fan via the lighting circuit, if it's timed use one of these:

http://www.tlc-direct.co.uk/Products/AA3PSW.html

 

[Timlouth]

Many thanks for the reply.
Do you know which regs refer. I am having a difference of opinion and want ammunition to further my argument.

Tim.

 

[Chri5]

Isolation of a fan is good practice, but it isn't a regulation.

The good practice comes from the (occasional) need to service / clean the fan and in some situations (such as rooms with no natural light) needing to use the lighting to see what your doing.

Switch on / off fans need no more than a switch or a fused spur, 3 pole isolations are only where the instal has perm and switched live feeds.

 

[Timlouth]

What I was after was a 17th Edition regulation referring to what could be added to lighting circuit.
I realise that bathroom extract fans can be added to the lighting circuit but I wanted to know what the rules are.
I am working on cabins that have a 6A MCB with 1.5 mm wire feeding the main lighting circuit and then 5 lights and extract fans spurred off to phone booths.
I want to know if there is a regulation that I can use to add weight to my argument that this is not good practice.

Tim

 

[Taylortwocities]

I dont believe there is a wiring reg that says you cannot.

Basically you have got a radial circuit rated at (nominally) 6 amps. The label on the consumer unit says "lights" but it could say

"lights, extractor fan, shaver point, TV amplifier and smoke alarm"

Its up to you what you connect to a radial so long as proper design principles apply.

There are restrictions on some radials - these may be Wiring regs or they may be other regs (Building Regs eg). For instance, a heater for a water vessel over 15 litres must be on a dedicated circuit.