Smoke alarm wiring

[iep]

What type of cable should be used for a hardwired smoke alarm system (domestic install)?

Not doing the commissioning myself but want to run the cable this weekend when the ceilings are down.

My guess is that 3 core and earth (1.5mm as I have some) should be okay but I don't know for sure. Ideally I'd run this past a spark but I may not have time before the ceilings go back up (bad planning on my part).

Thanks,

iep

 

[Taylortwocities]

Not enough information.

How many smoke alarms will you have?
Will they be interlinked, through the cabling, or stand-alone?

 

[iep]

Sorry should have said. Four smoke detectors and one heat detector.

Was planning on running interlinked with all five independently run back to a central box (at spur in the lighting circuit).

Absolutely admit my knowledge here is light. Any advice gratefully received.

Cheers,

iep

 

[PrenticeBoyofDerry]

1.00mm2 three core and earth will do!
but if your taking a feed of the lighting circuit, I would use the same CSA cable that is on that, so if 1.5mm on existing lights go 1.5mm, if 1.00mm go 1.00mm.
I assume there is no loading issues and the addition of 5 smokes will not cause a problem?
Personally would go for smokes on an independent circuit, if spare at board?

 

[RF Lighting]

Don't run them back to a central point. It's just making the installation a PITA for no good reason.

T&E from the CU to the first alarm, the 3 core and earth from there to alarm two, 3 core and earth from there to alarm three, 3 core and earth from there to alarm four, 3 core and earth from there to alarm five etc...

 

[iep]

Thanks for the advice guys. I do have a few spare slots in the C.U. so an independent circuit is a good plan.

Cheers,

iep

 

[RMS]

Yes,

It's also acceptable to feed them from a regularly used lighting circuit. Some manufacturers actually recommend this method. This way you can supply them locally from your closest lighting permenant line and neutral/cpc supply. Normally carried out when access back to the consumer unit requires more work, so if it's easy to do then go back to the consumer unit.

 

[Workers]

Also poor placement in some circumstances of the detectors.
As they should be away from the light because of possible smoke dissipation from the heat of the light if on.
However it is accepted.

 

[RMS]

Normally >300mm is deemed acceptable away from light fittings/obstructions.

http://www.connevans.com/information/aico_smoke_q_a.pdf

 

[Adam_151]

T&E from the CU to the first alarm, the 3 core and earth from there to alarm two, 3 core and earth from there to alarm three, 3 core and earth from there to alarm four, 3 core and earth from there to alarm five etc...

I'd do the first leg in 6243Y as well... that way if you use aico and want their silence/locate/test switch, then that can be lcoated adj. the con unit