Smoke detector wiring?

[Roger465]

Renovating a house at the moment, and have got to the smoke detectors. Their ceiling sockets are all over the place, but only half of them have detectors, and as far as I can tell, none of them work. They’re the kind which take a power supply from wiring in the ceiling, rather than just batteries.



What I’d like to know is are the wires to these things mains (little socket pictured below)? If so, they’re dead… do they go back to a fuse in the main fusebox, and have their own dedicated fuse there, or on a light circuit or something?



If it’s all a real mess, or electrically difficult, I’ll just take the sockets down and put ordinary battery detectors up, but I’d prefer to do it right using the existing wiring if possible. If that were possible, do these look like a current design to you, so maybe I can buy similar ones which will simply plug into the existing ceiling wiring?



Thanks

 

[sparkwright]

Wrong picture, surely?

 

[stillp]

Is that the photo you meant to post? Looks like a mirror light to me!

 

[Taylortwocities]

That's the photo of the fitting that you cannot get the lamp out of.

 

[Roger465]

Sorry guys, working on two laptops at the same time here & have screwed everything up... bear with me

 

[Roger465]

Right. Sorry about that. Note to self: Before asking daft questions on forums, check around a bit more first.



I’ve discovered a fuse missing in my fusebox, with some very faded writing on it which I now realise says “Smoke detectors” (you wouldn’t have been able to tell if you didn’t know, if you get me).



So I assume one or more of them was either constantly blowing the fuse, or more likely going off all the time. If you look at the label, through the nicotine, you can see it was made in 1990 (house built 1994, so about right), so they’re probably all knackered I’m guessing…?



So my (hopefully sensible this time) questions are (1) is that some kind of standard electrical connector which a modern detector will still fit; (2) is my best plan to take them all down, replace the fuse, buy a detector from Screwfix, and try it in each socket to see if it works OK – if so, buy a pile more?



http://www.screwfix.com/p/brk-670mb...up/81969#product_additional_details_container



Phew. Thanks View attachment 127180 View attachment 127181 View attachment 127180 View attachment 127181

 

[sparkwright]

Ignore the connector.

Take all of them down, and replace all of them with Aico detectors.

You will have to wire them in yourself though, so observe which wires are L, N and Interconnect.

Also, you will need to determine which rooms need optical, ionisation and heat.

 

[flameport]

Smoke detectors have a life of 10 years - yours are expired, and being full of nicotine they would be useless even if not expired.

There are no standard connectors - each manufacturer uses whatever they want, and manufacturers can and do change things over time, so it's unlikely you will get one to just plug in.

However the connections themselves are just L, N, E and an interconnect - very easy to fit a new connector should the new alarms require such a thing.

I would not recommend those BRK things, they are dreadful to fit as they attach to the backplate by twisting, the massive plug and wires always gets in the way, and they only fit on the plate properly one way, but can be made to jam on wonky in many ways.

These are far better: https://www.toolstation.com/shop/p69457
plate screws to the ceiling, wires connect directly to the plate, alarm clips to the plate by sliding.

 

[Roger465]

Ignore the connector.

Take all of them down, and replace all of them with Aico detectors.

You will have to wire them in yourself though, so observe which wires are L, N and Interconnect.

Also, you will need to determine which rooms need optical, ionisation and heat.

Thanks both. Not sure how to choose the type per room though... here's what we have at present. This is an L-shaped bungalow. Up the long arm of the L is a long hall going to the bedrooms and bathroom, and a dining room and conservatory off one side.

The living room is off the junction of the L, as is the kitchen, which then goes via a small utility room to a big second reception room.

There are (were) only 3 detector points fitted to the house - one at each end of the long hall, and one in the big 3nd reception room. Don't know the logic of that, but they were part of the original build of the house, as far as I can see.

All ionisation.

Should it be very different to this? Maybe building regs were different in 1994...?

Here's the wiring - not sure which wire is which. Obviously I can check for live if I put the fuse back...

 

[Iggifer]

Keep pulling, you might need to take the base down but up there behind it will be some connectors and then standard T+E/3 Core & Earth.

You should have a twin+earth and 3C+E at the first smoke from the board, two 3C+E at the second and a single 3C+E at the last smoke. You may not have a smoke with a twin+earth at it as some people will, unnecessarily feed the circuit in 3C+E from the board.

If this is the case you will need to establish which is Live & Neutral, you will then be left with the spare core which will be your interconnect. The earth will need to be connected to the brass terminal to keep continuity.

If you look on the Aico website there's a good guide about what device to put where, you know your house and layout so probably easier for you to look it at and decide what's best. I would recommend adding a Heat detector in your kitchen though - in a fashion recommended on the website (ie not too close to the oven/hob and certain distances away from light fittings and other distractions)

 

[Roger465]

Think it might be getting to the point where a spark is called for... I'll have a go at most things, but as Dirty Harry said in Magnum Force, a man's gotta know his limitations...

 

[Iggifer]

That's fair enough. In all honesty, it shouldn't be too pricey. I'd wager the cost of the smoke detectors will set you back more than the labour. Even with adding another, it's only a couple of hours work in a bungalow (assuming loft access to kitchen)

 

[Roger465]

Yeah… think I’m going to have get one in anyway. There’s all sorts of weirdness in this place – internal PIR detectors which blink at me, but no control box anywhere in the house, and no sounder box outside… think somebody’s just cut bits out and left others connected



Oh, and what the hell is this? It isn't the doorbell

Half way up the hall, above the airing cupboard door, with what looks a bit like a telephone wire disappearing into the ceiling in the airing cupboard...

 

[flameport]

Internal sounder for an intruder alarm.

 

[Roger465]

Internal sounder for an intruder alarm.

Aaaah, more mysterious parts of the alarm system. Got to get into the attic and find where all those wires go, but I want to wait till I have somebody else here to call the ambulance when I come crashing through the plasterboard...