Smoke Alarm - Mains, Link and Wiring

[PASUK]

Hello

I am decorating a few rooms in my house and have the opportunity to install mains powered smoke alarms as I have floorboards up and routing other cables.

I need to install:
1 for the kitchen
1 for a study
1 for the dining/living room
and 1 for the landing

I need them to be linked as the study is a garage conversion and wouldn't hear the alarm from the bedrooms.

I know the kitchen one needs to be a heat alarm but unsure what to get for the other rooms. ionisation / optimcal / combined. Any advice?

Also could anyone recommend a reliable brand/model which is reasonably priced?

I am also planning to run a circuit just for the alarms from the consumer unit, I have no idea what cable I need to buy?

Thank you

 

[JohnW2]

I am also planning to run a circuit just for the alarms from the consumer unit,

Not necessarily a good idea - many favour running alarms from a lighting circuit, so that you will be much more rapidly aware if something goes wrong with the power supply to the alarms.

I have no idea what cable I need to buy?

Installing a new circuit from the consumer unit would be 'notifiable work' in terms of the Building Regulations. If you undertook the work yourself, and notified the work to your local authority, the notification fee could, at worst, be 'a few hundred pounds' - hence it would be likely to be far far cheaper to employ an electrician who was registered to 'self-certify' (and who would know what cable to use), in which case the notification fee would be trivial. This is maybe another reason for not installing a new dedicated circuit for the alarms!

Kind Regards, John

 

[Taylortwocities]

Agreed, power your alarms from a regularly used lighting circuit.

Personally I usually install AICO EI series alarms. I would go for the Optical (EI146) as this won't sound off so much if you burn the toast!

 

[AndyPRK]

Use 1mm 3core and earth

 

[sparkwright]

Where possible, always try to run the supply for smoke alarms back to the consumer unit, BUT connect to the lighting circuit.

This way you have future proofed it, it can be on it's own circuit if there should happen to be a good reason for it.

As said, 1.0 mm2 3 core and earth cable.

It is usual to run 1.0 mm2 twin and earth from the supply to the first detector though.

However, on the subject of future proofing again, this is not necessarily a good idea, if you want to add a test switch later on.

Check you don't require a smoke detector in the hallway.

 

[PrenticeBoyofDerry]

I too would recommend Aico alarms you can either link them with three core and earth from a lighting point or use radio frequency bases, they do not need to be linked but do require hardwiring to a power source and setting up to talk to each other.

Heat for kitchen
Optical or multi for lounge hallway and landing
ion or multi for bedrooms

Also consider CO alarms if you have gas fittings.

 

[AndyPRK]

Aico even have an iphone app

 

[flameport]

Aico even have an iphone app

For what purpose?

 

[AndyPRK]

Wiring instructions
Info
Facts

 

[OwainDIYer]

Aico even have an iphone app

For what purpose?

Updates your facebook status if your house is on fire.

Tweets @firebrigade

Searches gumtree for cheap caravans within 5 miles.

 

[flyingsparks]

Aico even have an iphone app

For what purpose?

Updates your facebook status if your house is on fire.

Tweets @firebrigade

Searches gumtree for cheap caravans within 5 miles.

 

[PASUK]

Where possible, always try to run the supply for smoke alarms back to the consumer unit, BUT connect to the lighting circuit.

This way you have future proofed it, it can be on it's own circuit if there should happen to be a good reason for it.

As said, 1.0 mm2 3 core and earth cable.

It is usual to run 1.0 mm2 twin and earth from the supply to the first detector though.

However, on the subject of future proofing again, this is not necessarily a good idea, if you want to add a test switch later on.

Check you don't require a smoke detector in the hallway.

Thanks very much for this advice, very clear and helpful.
Very basic question... why the earth cable? reading the smoke detector install guide it just says it connects to the connector block but not connected to the detector, so I wonder why?

thanks

 

[JohnW2]

Very basic question... why the earth cable? reading the smoke detector install guide it just says it connects to the connector block but not connected to the detector, so I wonder why?

There is a general requirement that an earth is run to every point an electrical cable goes to, even if it's not currently required (in case the 'something' connected is subsequently changed to something that does require an earth) - and that may apply to alarm cable as well as everything else. There's also the consideration that by having an earth within the cable, it's more likely that a protective device will trip if some kind person puts a drill, nail or screw through the cable!

Kind Regards, John

 

[Taylortwocities]

It is also VERY useful when carrying out the tests on the wiring before it is put into service.
EFLI cannot be determined unless there is an "E"

 

[JohnW2]

It is also VERY useful when carrying out the tests on the wiring before it is put into service. EFLI cannot be determined unless there is an "E"

That's an interesting, and valid, point. Mind you, if the cable did not have a CPC/earth, then there would not really be an EFLI, in the usual sense, to measure!

Of course, if it were a TT installation, the EFLI would be an irrelevance, anyway

Kind Regards, John