Mains operated interconnected smoke alarm

Neptune · Apr 23, 2021

I fitted these into my own house a few years ago when everything was ripped open and hence, am familiar with the process.
However, on this occasion I need to fit these into a property that I let out and I don't have access to the ceiling void on ground floor.

I was thinking about using trunking and wanted to check on what type of trunking is neat and recommended for this purpose. Also, how will this merge into the existing light pendant (standard light pendant hanging from the ceiling).

Finally, I assume that I will need to trunk to the switch and not light if that's where the permanent live is. If this is the case, how will the trunking merge into the existing light switch?

Never had to use trunking before. Thanks in advance.

brianmoooore · Apr 24, 2021

Not yet.

loz2754 · Apr 24, 2021

brianmoooore said:
Not yet.

I give your comment a C3. ?

pirate · Apr 25, 2021

To clarify, I was commenting from a Scottish perspective.

loz2754 · Apr 25, 2021

pirate said:
To clarify, I was commenting from a Scottish perspective.

Ah. Different set of ~~riddles~~ rules.

Neptune · Apr 26, 2021

Thanks for all the responses. I really appreciate it.
My Local Authority has expressly stated that I need mains powered and cable interconnected smoke alarms. they do not approve the wireless system.

Once, I have confirmed the presence of permanent live in the ceiling rose I will use the trunking and clips mentioned to complete this task.

I also thought there was a "heat resistant" type 3 core and earth cable. Perhaps I should use that for the interconnect?

Thanks again

loz2754 · Apr 26, 2021

Neptune said:
I also thought there was a "heat resistant" type 3 core and earth cable. Perhaps I should use that for the interconnect?

No, the correct cable to use is PVC twin and earth, 1mm².

Twin and earth for the supply to the first smoke alarm, and 3 core and earth for the links from the first smoke alarm to the 2nd, from the 2nd to the 3rd, etc.

Neptune · Apr 26, 2021

loz2754 said:
No, the correct cable to use is PVC twin and earth, 1mm².

Twin and earth for the supply to the first smoke alarm, and 3 core and earth for the links from the first smoke alarm to the 2nd, from the 2nd to the 3rd, etc.

I was wondering if there is a heat resistant version of each of these cables or should I be using the conventional type?

Dartlec · Apr 26, 2021

Neptune said:
I was wondering if there is a heat resistant version of each of these cables or should I be using the conventional type?

You can get LSF (Low Smoke and Fume) twin and earth, but it's not necessary. Normal 3 core and earth will be fine for interconnected smoke alarms in your sort of application.

DJAndy · Apr 26, 2021

Neptune said:
Once, I have confirmed the presence of permanent live in the ceiling rose I will use the trunking and clips mentioned to complete this task.

If there is a ceiling void you might be able to use cable rods or similar to get a cable from your light fittings to the alarms without trunking. Takes longer but worth the effort.

[ElectriciansForums.net] Mains operated interconnected smoke alarm

Neptune · May 10, 2021

Morning Guys,
I've been advised that I require Grade D LD 2 interlinked mains wired detectors.
Can someone please advise if these would suffice:

Aico Ei141RC Easi-fit Ionisation Smoke Alarm 230V + 9V Alkaline Battery Back-up | Toolstation

• Long life ionisation sensor more responsive to flaming fires (paper, clothing) • Easi-fit base • RadioLINK base provides wireless interconnection • Low battery warning • Test/silence button • Fit in bedrooms BS EN 14604:2005 KM 552831. This alarm conforms to the latest British...

www.toolstation.com

Aico Ei144RC Easi-fit Heat Alarm 230V + 9V Alkaline Battery Back-up - https://www.toolstation.com/aico-ei144rc-easi-fit-heat-alarm/p49808 (kitchen)

I have also seen "optical" devices and don't understand the difference between these and the above ionisation ones.

Finally, are there any good practices in how the conduit should be laid out on the ceiling? For instance, should I go along the outer edge of the ceiling and then cut across to the detector or should the trunking go in straight lines across the ceilings, from one room to another.

I really appreciate your help with this.

Strima · May 10, 2021

You would need to buy the radio link bases with those. I’ve used them in the past and they’re very easy to instal and set up.

Where possible take the supply from the nearest light fitting, read the manufacturers instructions but generally they should be placed more than 300mm from any other fixture or wall. The bases are designed to accept 25x16 trunking and it would be advisable to use fire clips to support the cables.

Neptune · May 10, 2021

Strima said:
You would need to buy the radio link bases with those.

I was planning to hard wire the interconnect. Presumably the radio link bases wont be required in that case?

Also, can you please confirm that these meet the Grade D LD2 standard as I couldn't find this info anywhere.

Neptune · May 10, 2021

loz2754 said:
3 core and earth for the links from the first smoke alarm to the 2nd, from the 2nd to the 3rd, etc.

Is 1.5mm 3 core and earth required for this?

DPG · May 10, 2021

Neptune said:
Is 1.5mm 3 core and earth required for this?

You'll need 3 core for the link.

brianmoooore · May 10, 2021

DPG said:
You'll need 3 core for the link.

Dangerous advice to a DIYer!!
T&E is '3 core'. 4 core, otherwise known as 3 & E is required.

Mains operated interconnected smoke alarm

Neptune

brianmoooore

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loz2754

pirate

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loz2754

Neptune

loz2754

Neptune

Dartlec

DJAndy

Neptune

Aico Ei141RC Easi-fit Ionisation Smoke Alarm 230V + 9V Alkaline Battery Back-up | Toolstation

Strima

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Neptune

Neptune

DPG

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brianmoooore

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