Wiring Domestic heat and smoke detectors

[Nathwri]

Hi I have recently been to look at my friends newly built extension. The guy asked me about the fire alarms and how I would go about doing them as he wasn't sure . I advised that the way to meet regulation would be to take the existing Battery powered alarms down, and hard wire from an RCBO in the mains to the first detector and then link these going from one to the next with a 3 core cable.

He looked into this came back and said that it is possible and legal to take and existing feed from a nearby socket or line/neutral from a light to supply one detector and then have the others wireless controlled from this.

I haven't worked on domestic property's for over 5 years so the above method is simply what I used to do when I was working for a domestic company and this seamed logical as you are always having a mains supply to each detector fed by an independent RCBO. Also you had the 3rd core for feeding the signal to all the other detectors when one went off.

Please can you guys clear this up for me as it's doing my head in and don't like advising people wrongly and looking a twit!

 

[Anthony S]

Radio linked bases, but each base needs a 230volt supply if he don't want them hard wired.

 

[TJ Anderson]

Many electricians, myself includes, prefer to power them from a regularly used lighting circuit as they would quickly recognise if the supply to circuit was lost.

 

[telectrix]

Many electricians, myself includes, prefer to power them from a regularly used lighting circuit as they would quickly recognise if the supply to circuit was lost.

agreed, but not from a socket circuit.

 

[Nathwri]

So my original method of doing things isn't incorrect but just causing more work than is needed?
Yes I would have thought not a ring circuit for sure.So in essence you could just wire each Radio linked base to the nearest ceiling rose as long as there is a permanent line and neutral there and then interlink them via the radio signal?

In all fairness I hadn't even heard of the radio link bases, I've just looked them up and they seem fairy expensive compared to hard wire ones with normal bases.

 

[Anthony S]

The costs of the bases will offset the cost of running cables etc and making good after if the place is decorated and not to be messed up. Think about

 

[urbanmonkey]

Check your routes, you may be able to get away with just one radio base upstairs and one downstairs or a similar arrangement depending on ease of access.

 

[tazz]

The answer is weather its a new build or existing.....new build then you would hard wire, existing build you use wireless bases....A conversion, you could mix both. Just make sure the correct detection is fitted in the correct locations to meet Part 6

 

[Octopus]

Hold on. Why weren't they fitting when the extension was built. Most building inspectors insist on them

 

[R G]

Hold on. Why weren't they fitting when the extension was built. Most building inspectors insist on them

Exactly what I was thinking , after all any new extension or new build has to be designed accordingly ,I always factor in all smokes and heats when designing and I assume everyone else does as well to satisfy BC , if the house is nicely decorated then this is to be discussed and if cables can't be run then at its design stage radio linked units specified ,

 

[tazz]

Thats a point...any extension would move the circulation area. And BC would insist on detection

 

[Octopus]

Thats a point...any extension would move the circulation area. And BC would insist on detection

In which case has it been built without building control being involved?

 

[Nathwri]

Sorry guys,I failed to mention the building is erected and still in the joinery first fix phase. The guy was asking my advice as he knows I have worked in domestic property's before. He looked into his building regs given to him when he planed the build and told me about the radio type detectors after I had said they are to be hard wired. As said before I didn't have a clue what they were as I am not in that part of trade anymore.

Thanks for the info guys

 

[Octopus]

Sorry guys,I failed to mention the building is erected and still in the joinery first fix phase. The guy was asking my advice as he knows I have worked in domestic property's before. He looked into his building regs given to him when he planed the build and told me about the radio type detectors after I had said they are to be hard wired. As said before I didn't have a clue what they were as I am not in that part of trade anymore.

Thanks for the info guys

then ask ask the sparky contracted to do the work

 

[Nathwri]

then ask ask the sparky contracted to do the work

I'm not in contact or know the guys who he has coming in to do the work so I'm not going to cold call them and start hounding them about how they wire their fire alarms lol... I just wanted some friendly advice as I was not aware of this new method. The guy who's property it is was just asking me how I would go about it as he wasn't too keen in them causing a mess in the old hour connecting the existing fire alarms up! Next time I'll tell him to just ring the contractors up