smoke alarm

ashley124 · Posted: Sun Oct 01, 2006 1:17 am Post Subject: smoke alarm

could u add a electric smoke alarm on a lighting circuit?

sorry for all the questions tonight peeps

breezer · Posted: Sun Oct 01, 2006 9:10 am Post Subject:

yes

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paulfree · Posted: Sun Oct 01, 2006 12:07 pm Post Subject:

i think it may need a seperate supply not on the rcd circuit.

breezer · Posted: Sun Oct 01, 2006 12:09 pm Post Subject:

it doesn't and lights are not usualy on the rcd side

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plugwash · Posted: Sun Oct 01, 2006 12:13 pm Post Subject:

you can either put smoke alarms on a local lighting circuit or on thier own dedicated circuit.

the trouble with the first option is that interlinking alarms on different circuits could be dodgy depending on exactly how the interlink is implemented and in most houses no one lighting circuit will be local to everywhere.

breezer · Posted: Sun Oct 01, 2006 12:16 pm Post Subject:

but its improbable he is putting in interlinking detectors. Besides if they are interlinking they only need one feed

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paulfree · Posted: Sun Oct 01, 2006 12:25 pm Post Subject:

im pretty sure they should be on a seperate supply not through the rcd the cables dont have to be ran seperate like fire alarm systems it can be ordinary twin and earth or 3 core and earth fo interconnecting between alarms each alarm has to be inter connected to each other alarm so as they will all be set off in the property and i think now they recommend a heat sensor alarm for the kitchen so as not to get false triggers while burning the toast its a bit more complicated than just connecting from the nearest ceiling rose but it does make sense.

didthathurt · Posted: Sun Oct 01, 2006 12:36 pm Post Subject:

A smoke alarm that incorporates a back up power supply can be connected into a local, regularly used, lighting cct, though a dedicated supply is recommended. A local regularly used lighting cct means, practically, a cct in the same house that is used often enough for a loss of supply to it to be identified in a relatively short period of time - I don't think the interlinking issue affects this.

The RCD bit says that it should not be on an RCD, if it is, it should be on its own RCD and definitely not be on the same RCD as protects sockets liable to provide outdoor equipment. That can be a real problem in TT earthed houses that have a non-split load board (not uncommon in installations as new as, say, 6 years old!).

Ashley still needs to come clean, though, over exactly what it is he is doing.

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