Installing wired smoke alarm to light circuit

LeeUK

LeeUK

LeeUK

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I want to install a wired smoke alarm at the top of my stairs. Is it safe to cut into the lighting circuit to wire it up or does it need it's own circuit?

If it needs it's own circuit then that is pretty much out of the question at the moment.
 
Depends if it has battery backup or not,
Don't want to die just because a blown bulb takes out the isolator.

On the plus side, if it trips then you will know about it, although I'd rather use a voltage fail alarm to indicate that, fires happen in daytime too.



IMO all critical equipment needs to be on it's own alarmed circuit, but electricians generally bodge it into the lighting circuit.
 
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Then lighting circuit is legal.

To me this is a risky way of doing it, although interestingly power failure devices are less common than I thought.
Personally I'd want to know the second the smoke alarms are off or the fridge circuit is down.

I think the 17th fudges it by saying they don't want the user to isolate the circuit. But their solution is still crap.



Edit.
eBay.com sells power failure alarms for $5, wire up a socket next to the consumer unit, label it as lighting circuit only and plug it into that.
Much safer, alarm sounds when smoke alarms are offline.
 
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Lighting circuit seems the most sensible way to me. They almost all have battery backup, and if the lighting circuit RCB trips, then you'll realise far sooner than if a separate alarm circuit trips.
 
bitslice said:
Depends if it has battery backup or not,
Don't want to die just because a blown bulb takes out the isolator.

On the plus side, if it trips then you will know about it, although I'd rather use a voltage fail alarm to indicate that, fires happen in daytime too.



IMO all critical equipment needs to be on it's own alarmed circuit, but electricians generally bodge it into the lighting circuit.
Click to expand...

Being a sparky I had to lol at this! In an ideal world most things should be on its own circuit but unfortunately if you quoted your jobs that way you'd never get any work as few people are willing to pay!

Edit : To op nothing wrong with wiring into the lights just make sure you connect to the loop (permanent live).
 
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It is a bodge though :)
relying on someone to turn on a light switch to determine if a breaker has tripped?

Nobody would get away with that in an industrial control system,
"ere mate, if this light doesn't come when you turn the kettle on, it means the reactor cooling system is offline"

:D
 
Aico EI166RC optical smoke alarms, they have a 10 years rechargeable lithium battery for £20 on Ebay.

Fitted three here, but I also interlinked them with a separately available Ei168RC RadioLINK system base,off Ebay about £18, as it was too awkward installing wired interlinks between alarms.

Look at others smoke alarms which use a replaceable 9v PP3 battery, but too much hassle replacing batteries.

I also have spured off the light circuit for the smoke alarms:o, but due to alarms location, it difficult running a seperate 3 amp circuit for them which I would prefer.
 
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I'd be more worried about extending your lighting circuit and not being RCD protected. If you are still on 3036's I'd get someone in to give you a price for a board change.

Not a thing wrong with coming off of the lighting circuit for smoke alarms. Buy the ones Nightglow has mentioned.

If you have a fault on your lighting circuit you will know pretty soon about it.. And the Aico alarms have LED status., you will know with a quick glance if power is out, being battery back up they will still work for a while on battery and once that battery starts to run low, they will beep once a min. If you fail to notice this then a smoke alarm isn't for you.

Bitslice just lol.
 
Aico EI166RC rechargeable lithium battery when fully charged, will give 6 months backup without mains power.

Also being a optical smoke alarm, it's very good for smouldering fires, best locations,top of stairway, lounge for them, I also got one in utility room.
Very sensitive alarm, burnt the toast the other morning, & the one in utility room went off along with the others, no way you could sleep through the racket, thankfully there is a silence button you can press.

Decided fitting one in the attic would be also a good idea.
 
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Thanks, will take advice on board. Will go for optical alarms also.

The alarm I already have in the hallway is due for renewal too as the sticker on it says replace by April 2014.

I was going to just replace that one with only a battery powered alarm due to not having easy access to the light circuit to wire one up.
 
bitslice said:
It is a bodge though :)
relying on someone to turn on a light switch to determine if a breaker has tripped?

Nobody would get away with that in an industrial control system,
"ere mate, if this light doesn't come when you turn the kettle on, it means the reactor cooling system is offline"

:D
Click to expand...

Any more drivel you would like to talk?

Sincerely,

5839 and 17th edition fire alarm engineer/electrician.
 
lewism said:
Any more drivel you would like to talk?

Sincerely,

5839 and 17th edition fire alarm engineer/electrician.
Click to expand...

So no defence for what is clearly not a fail safe installation?
Call yourself an engineer, lol.

Scenario: Battery fail, circuit tripped, alarm offline.
 
It's a domestic installation mate, not many fail safes are built into it. It's just not cost effective unfortunately.

Still no need to be saying electricians are bodging smoke alarm installation.
 
ZG002 said:
It's a domestic installation mate, not many fail safes are built into it. It's just not cost effective unfortunately.

Still no need to be saying electricians are bodging smoke alarm installation.
Click to expand...

Yep I understand that, I just think it's worthwhile considering why we do stuff a certain way and it that always the best way. Having pointed out a possible failure mode I wouldn't expect an engineer to just scoff.

I never meant to imply electricians bodge something, they have to work to 17th, I was using the term in the colloquial sense of "fix".

I'd still regard the current reliance by the 17th for a user noticing as being a poor solution. It's not their job to notice, it is the systems job to remove all avenues of failure. Otherwise it's not a fail safe system.
Compare that to all the other improvements in wiring which are fantastic, ignoring this one seems odd.

17th rationale.
Put it on a lighting circuit, more likely for a bulb to trip it but then the user notices
Vs
Put it on a separate circuit, but the user may isolate that circuit and nobody will realise.

Both have presumptive flaws tbh, hence my suggestion.




/
 
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Decided not to bother wiring up the alarms.

I've installed 2 new battery powered FirstAlert Optical alarms this afternoon from Screwfix. Job done for now.

I'll go for wired alarms when I eventually have the house rewired.
 
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