New smoke alarms

[xr4x4]

Hi all,

Currently have a 2 year old house with mains fire alarms fitted when the house was built, one in hall, one on landing. This is (I assume) is connected to the lighting circuit, as there isn't one in the cu labeled smoke alarms.

Need to install new alarms all over the house for loft conversion and plans say they must be connected to a separate circuit.

Do I need to run a new circuit from cu (major pain) or just use existing wiring and extend?

Thoughts and facts welcome.

Thanks.

 

[Spark123]

They are fine connected to a regularly used lighting circuit, however if the plans say a separate circuit then you are a bit limited, unless you can get them changed (assuming you want to comply with them)

 

[sparkwright]

As above. The preferred method (at the moment) is connecting the alarms to a lighting circuit.

Best check first certain how vital it is that the alarms are on their own circuit.

There's a chance your existing alarms are on their own cable from the consumer unit - but has been tapped into the lighting MCB. IF this is the case (you never know) then it may be easy to adapt it.

I would consider it good practice, where possible, to run a smoke alarm cable back to the consumer unit, so you have the option of connecting it to the lights or on it's own circuit. This is just one of my quirks though, so there's no requirement to do it this way.

 

[xr4x4]

Ok, thanks lads, I'll have a look Monday.

 

[PrenticeBoyofDerry]

There is nothing in the regulations stating that Smoke alarms have to be on a dependant circuit and unless the property is complexed design you would only require a smoke alarm on each floor level, normally in hall, landing and converted room.

 

[xr4x4]

To remove the need for replacing (pretty much) all the bloody doors for fire doors, we've decided that it would be cheaper and easier to use more smoke alarms.

We have checked this with BC and they are ok with this, basicly the smoke alarms need to be in all liveable rooms and a heat detector in the kitchen and one fire door on the new bedroom in the loft.

 

[PrenticeBoyofDerry]

Would a wireless system be less disruptive? They still require some cable connections but the they are linked via radio signals.

 

[mfarrow]

The most common reason for having smokes on lighting circuits is that you are most likely to notice when the power to them has failed. I can understand the logic to this, however I feel is is misguided. Most smoke alarm circuits are connected to only smoke alarms. Equipment which can in many cases be on a non-RCBO circuit, to low current devices with low failure rate. Short of a nail through the cable, I doubt you'll ever see a problem with it.

Smoke alarms will also tell you when they're off because the low battery alarm will start whining at you day and night. Ignore or take the battery out at your peril.

I do not have smokes on our lighting circuit because we have a security timer on the downstairs lighting for when we go on holiday. Also I'd run the battery down each time I want to work on the lighting. There are also lots of people replacing lights etc and leaving wires out/incorrectly connected. sparkwright's suggestion helps this a bit but not many do this and just connect to the lighting circuit anywhere they can.

 

[xr4x4]

Would a wireless system be less disruptive? They still require some cable connections but the they are linked via radio signals.

Possibly.. I'll look into it.

I'm guessing tho that the price of them will rule them out.

 

[PrenticeBoyofDerry]

http://www.aico.co.uk/How-do-I-wire-RadioLINK.html