disused mains smoke alarms wiring

[lostheadnail]

Hi
My mum has 3 old mains base units, wired to mains. The tops (i.e. the detector parts) are long since gone having malfunctioned some years back. I have replaced with three FireAngel 10 yr LiIon alarms. thing is the old base units look ugly and are still screwed to the ceiling and connected (to what I am not sure)

. The wires seems to have been clipped onto the joist so hardly any movement. I want to remove the old base units and make good the ceiling but what to do with those pesky live wires? The consumer unit has an entry labelled lights/smoke alarms so I guess everything is spurred off the lighting circuit (each unit is near to a ceiling light).
There are 2 cables entering the unit: twin and earth, and a 3 core and earth (T&E + yellow, I seem to recall)
Can anybody please advise the safe way to render the wiring safe; I feel that just snipping them off, taping over and pushing the cable into the ceiling void is not right?

 

[333rocky333]

Are you sure you should remove them, they may be a Building Regs requirement, i think having at least 1 mains unit has been a Reg for some time in some homes, so may vary with age of premises, poking old wiring in ceiling is not an ideal option,

 

[Robin0577]

Removing them would be a backward step and possibly even illegal if building regs require them to be fitted. You can still buy alarms to fit those bases, all Ei 140 series will fit. https://www.tlc-direct.co.uk/Products/EI141RC.html

 

[mattylad]

yeah the 10yr ones are not always good for the 10 years they say they are.
Get some mains ones again.

 

[lostheadnail]

thanks guys.
I think I'll go for the mains powered ones then. Presumably the backup battery will last a long time? I should have posted this before buying 3 new battery powered ones ... I only realised when I was "up there" expecting to remove the old plate and put the new unit in its place!!

Just one more thing. There are 3 of these mounted in the landing/hall areas above the stairs in the the floors (it's a 3 floor semi about 18yrs old) .. would the standard "
Mains 141 Ionisation Smoke " be the right choice? I was bewildered by the range of different types available.
Thanks

 

[AndyPRK]

Looking at my Aico app

They say optical for landing.

Ionisation for bedroom

It's good to have mains ones, if the alarm is triggered on one floor, all go off

 

[EFLImpudence]

I was bewildered by the range of different types available.

Google it. Loads of information.

 

[AndyPRK]

Them base do look like the aico brand

If you went for them (look on eBay) you maybe able to just slide new ones onto the base with no damage to ceiling.

What are the chances of that

 

[flameport]

Presumably the backup battery will last a long time?

It's only used if there is a power failure. Will probably last for the life of the alarm(10 years) if power failures are infrequent or never.
Even if not, it's just a 9 volt PP3 item available for a couple of quid anywere.

 

[Taylortwocities]

it's a 3 floor semi about 18yrs old

Then you must have mains interlinked alarms with battery backup. Put the FireAngel things on eBay.

 

[SimonH2]

To expand on that ...
They need to be mains with battery back-up - that way they will keep working for a long time and the temptation to just take the batteries out when they run down is removed.
They need to be interlinked - that way, when one is triggered, all of them sound which means those sleeping on the top floor (where it's too high to climb out of a window and jump down) have some chance of being woken up before the fire from the kitchen has made the stairs impassible.
You can use radio links for interlinking, but that's a backwards step when the wiring is already in place - I would never use radio when it's possible/practical to use fixed wires.

 

[Taylortwocities]

You can use radio links for interlinking,

From the look of the base, they should already be hardwired interlinked.
@lostheadnail show us the connections to the terminals on the alarm base please.