'Isolator'/switch for smoke etc. alarms?

[Murdochcat]

Ei3016 Optical Smoke Alarm | Aico

The Ei3016 Optical Smoke Alarm is best for detecting slow, smouldering fires in the home in the living room, bedroom, hallway, landing, or dining room.

www.aico.co.uk

This type. Never had issues with these so why do you think they are frowned upon

 

[sparkymarka]

They never last 10 years …..

 

[sparkymarka]

Ei3016 Optical Smoke Alarm | Aico

The Ei3016 Optical Smoke Alarm is best for detecting slow, smouldering fires in the home in the living room, bedroom, hallway, landing, or dining room.

www.aico.co.uk

This type. Never had issues with these so why do you think they are frowned upon

That type has a rechargeable lithium battery

 

[JohnW2]

.... This type. Never had issues with these so why do you think they are frowned upon

No, I'm not talking about that. I use those, but they are mains-powered with lithium-ion battery back-up.

The ones which I said are 'frowned upon' (even though I would personally be comfortable with them) are powered only by a non-rechargeable (and not replaceable) lithium battery with an alleged 10-year in-service life - such as the Aico Ei650i

 

[Murdochcat]

Kiddie are pure carp

 

[JohnW2]

Kiddie are pure carp

Maybe they are (I have no personal experience).

However, that's got absolutely nothing to do with the question I posed when I started this thread, nor even any of the subsequent off-shoots of the discussion!

 

[JohnW2]

Maybe I'm scraping the very same barrel as you, with your need to have the alarms on your lighting circuit .... As Sparkamarka pointed out, most/all such alarms, bleep annoyingly, anyway, making them incredibly difficult to ignore.

I would suggest you are wrong there, one would need to be really stupid, not to be able to appreciate that a regular noise from an alarm, was meant to convey that something was amiss with the alarm.

I thought I was right, but have just studied the Aico documentation to confirm and, furthermore, have 'done the experiment' to further confirm (as far as I can) that the documentation is telling the truth [although I do not have any switch, or FCU, I do have easy access to the point where the alarms are fed from the downstairs lighting circuit, so was easily able to disconnect the mains supply to the alarms ].

I have four interconnected Aico 3000 series alarms. When I disconnect the mains, ALL that happens is that the (usually constantly 'on') green LED on each alarm goes out and, instead flashes (for a fraction of a second) once every 48 seconds. I doubt that many people would notice that, particularly in a house like mine with very high ceilings. Of most importance to the discussion, nothing 'beeps'.

I obviously have to take Aico's word for it but, apparently, if the state of battery charge gets worryingly low, it then starts beeping (I suspect very briefly) (they call it 'chirping') once every 48 seconds - but that could presumably be weeks or months after the mains supply had failed and, even then, might not be 'compelling enough' to result in immediate action by the occupants (since occasional 'chirps' might well not be very 'annoying').

I would say that this underlines my personal view that, at least with Aico alarms, it is much more sensible to have them powered from a constantly-used lighting circuit than from a 'dedicated' circuit of their own.

 

[Harry Bloomfield]

I obviously have to take Aico's word for it but, apparently, if the state of battery charge gets worryingly low, it then starts beeping (I suspect very briefly) (they call it 'chirping') once every 48 seconds - but that could presumably be weeks or months after the mains supply had failed and, even then, might not be 'compelling enough' to result in immediate action by the occupants (since occasional 'chirps' might well not be very 'annoying').

That seems to suggest a very poor design.

 

[JohnW2]

That seems to suggest a very poor design.

Maybe it is (if one want to 'annoy' occupants in the event of a mains failure).

However, Aico are one of the most widely used and most 'respected' brands of alarms, so they must feel that their design is satisfactory, and countless people are seemingly happy to use (and recommend) their products.

Whatever, as I wrote, at least in the case of Aico alarms I think it vindicates my personal view about the most desirable mains power source

 

[JohnW2]

I have four interconnected Aico 3000 series alarms. When I disconnect the mains, ALL that happens is that the (usually constantly 'on') green LED on each alarm goes out and, instead flashes (for a fraction of a second) once every 48 seconds. I doubt that many people would notice that, particularly in a house like mine with very high ceilings.

... I might have added ... and it's a pretty small LED at the best of times (whether on continuously or flashing every 48 secs), so even less likely to be noticed ...

 

[Harry Bloomfield]

I might have added ... and it's a pretty small LED at the best of times (whether on continuously or flashing every 48 secs), so even less likely to be noticed ...

Even fed via a lighting circuit, it still doesn't guarantee your alarms are getting their mains supply - they could be omitted during repairs/upgrades/modifications, or the internal mains adaptor could fail. The only near certain way, is a mains failure bleep, built into the alarm itself. A regular bleep from an alarm, is near impossible to ignore for long.

 

[JohnW2]

Even fed via a lighting circuit, it still doesn't guarantee your alarms are getting their mains supply - they could be omitted during repairs/upgrades/modifications, or the internal mains adaptor could fail.

Sure. The same is true of a dedicated circuit - the circuit could still be working fine, but mains supply not getting to one or more of the alarms. However, common things being common, having the alarms running off a lighting circuit make it very likely that one will immediately know when the alarms are not getting mains.

The only near certain way, is a mains failure bleep, built into the alarm itself.

To be fair to Aico, the beeping/chirping does start when one is approaching (probably a fair way off) the point at which there is a risk that the alarms will stop working because the batteries have gone flat. One therefore may well not notice the alarm telling one that the mains has failed (just the occasionally flashing LED) but is much more likely to notice if/when there is any risk of the alarms stopping working. It's therefore essentially a 'safe' design.

A regular bleep from an alarm, is near impossible to ignore for long.

Often yes, but, as I've said, I'm not necessarily convinced that will always be the case.

Two or three years ago, a CO alarm owned by my neighbour which had a non-replaceable and non-rechargeable battery started beeping, to indicate that its battery was getting old. Since she couldn't stop in beeping, and didn't want to get bin men thinking it was a bomb, she threw it into her back garden 'to stay there until it shut up'. Two or three years later, it is still beeping every couple of minutes, but I've got so used to it that I don't even 'notice' when I'm in my garden close to hers

In case you, or anyone, is interested, this is what the three (green, yellow and red) LEDs and the 'chirping' on Aico 3000s are meant to do and
when ....

 

[Harry Bloomfield]

To be fair to Aico, the beeping/chirping does start when one is approaching (probably a fair way off) the point at which there is a risk that the alarms will stop working because the batteries have gone flat. One therefore may well not notice the alarm telling one that the mains has failed (just the occasionally flashing LED) but is much more likely to notice if/when there is any risk of the alarms stopping working. It's therefore essentially a 'safe' design.

Are those alarms mains interlinked? If they are then would the interlinking still work, during a mains failure? Obviously they would fail to all trigger if the wiring failed to one or more of the alarms - another plus point for a mains fail bleep.. It ensures both that the mains supply is active, and that the interlink is working.

 

[JohnW2]

Are those alarms mains interlinked? If they are then would the interlinking still work, during a mains failure?

We had that discussion (when we were talking about cable colours). Although mains-powered,and using the mains to charge the battery, the 'interconnect' must be at ELV, since the 'interlinking' does still work it the absence of mains.

As I said in that other discussion, had the interlinking been at mains voltage, not only would it not work in the absence of mains, but it would have put Aico in conflict with BS7671, since their instruction to use 'black' to identify the 'interconnect' conductor would have been trumped by BS761's requirement for it to be sleved in brown

Obviously they would fail to all trigger if the wiring failed to one or more of the alarms - another plus point for a mains fail bleep.. It ensures both that the mains supply is active, and that the interlink is working.

As above, the interlink works in the absence of mains. Failure of the actual interlinking (e.g. due to a wiring problem) could only be detected by 'manual testing';

I would have no major problem with an audible warning of mains failure, but don't really need it, since I would rapidly become aware of failure of my ground floor lighting, and consider other scenarios resulting in mains not getting to the alarms to be exceedingly improbable!
As for 'minor problems' (of having an audible warning of mains failure) if it were loud and persistent enough to be 'annoying'; in the manner you would like, it would be somewhat a case of 'adding insult to injury' if I had to endure that additional 'annoyance'' for the full duration of a protracted power cut