mains smoke alarm
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brickiepaul
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mains smoke alarm

by brickiepaul » Mon Sep 01, 2008 5:57 pm

Hi All

I need to install a mains smoke alarm (with batt back up), ideally i'd like to put it on its own fuse but this would mean chasing out one hell of a long way to get to the consumer unit.
Is it acceptable to spur off of the downstairs lighting circuit? and would this be inline with current regs?

Many Thanks

BLAKEY1963
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Re: mains smoke alarm

by BLAKEY1963 » Mon Sep 01, 2008 10:20 pm

[quote="brickiepaul"]Hi All

I need to install a mains smoke alarm (with batt back up), ideally i'd like to put it on its own fuse but this would mean chasing out one hell of a long way to get to the consumer unit.
Is it acceptable to spur off of the downstairs lighting circuit? and would this be inline with current regs?

Many Thanks[/quote]

BRICKIEPAUL
Looking at REG 560.7.1 , page 153 of BS 7671 : 2008
17th Edition Wiring regs , states :
Circuits of safety services shall be independant of other
Circuits.
I know some Local Area Building control officers
overseeing plans for alterations , extensions , and
new properties , have in my area specified smoke
alarms to be on thier own circuit.
If on lighting circuits , which have also been common
practise , then a fault on the lights , would also
isolate the smoke alarms , although they have thier
battery back up
IF i install mains smoke alarms with battery
back up , i put them on a separate circuit.
They are identified as an essential safety
Service are separate from everything else
and when inspection and testing is carried
out , it is clear to identify them as sensitive
equipment when insulation testing the
circuit.
You could consult local area building control
in your area to see if they would prefer
a separate circuit arangement or not.

BLAKEY 1963

desperado
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by desperado » Fri Jan 16, 2009 7:54 am

Connect to seperate circuit where possible otherwise regularly used local lighting circuit is ok but be sure to install a fused connection unit adjacent to the smoke alarm

sparx
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Location: The fifth continent.

by sparx » Fri Jan 16, 2009 5:33 pm

Hi LABC here take the very sensible view imho that Fire Alarms are safety circuits , smoke alarms are not.
see 560.4.1 page 152
If on seperate circuit they could trip off and battery back up go dead over a holiday period say & there would be no way of telling, but if on local lighting circuit it would be obvious when circuit is dead & less chance of them being deliberately turned off.
Desperado, why put in FCU? it could blow fuse and you are back to not knowing it's dead! If they were on seperate circuit lowest mcb normally used is 6A so they are designed with that in mind.
love to hear reasons as I hate to miss anything,
regards SPARX

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