Mains powered smokes taking live off the light switch

[cfsfire]

Been to quota for a fire alarm today and one electrical company has quoted for mains powered smokes and told the client the live is not in the ceiling roses but in the light switch and they will run trunking from the switch to the position of the detector and take the live and neutral from the light switch.

Question. Is the compliant to 17th edition?? I know you can power the smokes from the lighting circuit but dosent sound right to me taking it from the LS even if it is ok it dosnt sound very good pratice?

Thanks guys,

 

[Lou7]

I've said about neutrals at switches before, but everybody on here says it's ok, therefore you are alright to pick up supply from the switch.
I've got a feeling that it's ok to feed smokes from lighting circuit as long as they heve battery back up.

 

[Spudnik]

Its perfectly ok to feed the smokes from a regularly used lighting circuit.

Not sure about the trunking from the switch though but it sounds like thats your only option.

If you are having the floors up anyway, you could always trace the circuit wire in the ceiling above and bring that into your smoke and interlink cable from there.

 

[cfsfire]

Thanks for your help. I am a fire company so 99% of the time only install "fire alarm systems" on this occasion we have been asked to install a LD2 and normally we would wire them on a dedicated circuit taken from the local lighting circuit. But the other company quoted it the way i mentioned above and it just dosnt sound right and the client cannont have any floorboards removed at all.

One of those jobs that will be a bit of a bugger!!

Cheers,