Mains operated interconnected smoke alarm

[Neptune]

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.

 

[Dartlec]

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.

Grade D of the standard basically means mains powered with backup battery.

As of the 2019 BS 5839 standard there are now two levels though -

• Grade D1: the stand-by supply must be tamper-proof and last the full life of the alarm
• Grade D2: the stand-by supply is user-replaceable and will not last the full life of the alarm

So the one you've linked with a 9V battery would be Grade D2. Grade D1 is the type with a tamper proof lithium rechargeable battery installed.

Part B of the building Regulations suggests that Grade D2 is acceptable, so you would be covered.

LD2 then refers to where the alarms cover...

• LD2 – A system incorporating detectors in all circulation spaces that form part of the escape routes from the premises, and in all rooms or areas that present a high risk of fire to occupants.

As I understand it that means staircases or hallways (circulation spaces - one per level unless the hallways are long), with a heat alarm in the kitchen. Some guidance suggests the main lounge as well, but I don't believe that is set in stone - if there was an open fire in there then it could be said it presents a high risk of fire....

Optical or Ionisation are the different types of methods of detection, and each work better for certain types of fires (smouldering/flaming, etc). In general, optical is less prone to false alarms and are now the recommended option. They are less sensitive to smoke from toast, or steam from a shower room, though they are not recommended for use in a kitchen - a heat alarm is the preferred option there)

Ionisation alarms might be suitable for upstairs landings or stairwell - they are faster to react to fast flaming fires from paper, wood etc.

As previously mentioned, if you run the wiring in trunking, then you should use fire-rated cable clips to ensure against premature collapse of the wiring in the event of a fire. This applies to all trunking and cabling, not specifically ones supplying fire alarms though.

There is no specific 'right' way to run trunking on the ceiling - as long as the cabling within it is protected against premature collapse. It may be easier/neater to run around the edges, or the shorter direct route may be preferred.

3 Core and Earth is what you'll need for hard-wiring between then, though 1mm would be fine too.

 

[DPG]

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

Apologies, should have been clearer. Was agreeing that 3 core and earth is needed rather than twin and earth.

 

[i=p/u]

I smell smoke, good luck.

 

[Neptune]

Couple of further questions on this please:

- When slotting the trunking into the smoke detector, does some of the top and bottom section of the trunking disappear into the detectors base? I am trying to determine how neat my cut on the trunking needs to be.

- Secondly, when I am passing through walls (brick) as I go from the ceiling from one room to another, what are your recommendations on making this entry? I have an SDS drill but thought that it may not work right in the corner of the ceiling and wall.

- Thirdly, whilst the smoke detectors need to be daisy chained with the 3 core and earth cable, how do I install an Aico Fire Control Switch? Remote Control Alarm Switch 230v Mains - https://www.cef.co.uk/catalogue/products/1148678-remote-control-alarm-switch-230v-mains?gclid=16b5a446064114559754c4ddd79e91a2&gclsrc=3p.ds&msclkid=16b5a446064114559754c4ddd79e91a2

Is this just like another smoke detector in the sense that it should be included in the daisy chain i.e. one cable in and one out to the next detector?

Thanks for your continued support.

 

[Mike Johnson]

You need to get hold of "Electrical Contractors Handbook" Guides & Publications - Aico - https://www.aico.co.uk/technical-support/guides-publications/ free from Aico as a download or by post.

 

[Lister1987]

You need to get hold of "Electrical Contractors Handbook" Guides & Publications - Aico - https://www.aico.co.uk/technical-support/guides-publications/ free from Aico as a download or by post.

Also available as an app on Android

Aico Handybook - Apps on Google Play

For Electrical Contractors

play.google.com

 

[Lister1987]

Smoke alarms are not covered by an EICR, other than the mains feed.

Very much dependent on the Inspector. If you have working knowledge of 5839-6 then you can code it against 560.10, adding on relevant clauses in 5839-6 to bolster the inclusion in scope. BS7671 says in the early pages it is not exhaustive and can be supplemented by other standards, here is a perfect example of that in action.

 

[Neptune]

I do plan to go through the suggested booklet but would really appreciate a few pointers on the below as I am pushed for time.


When slotting the trunking into the smoke detector, does some of the top and bottom section of the trunking disappear into the detectors base? I am trying to determine how neat my cut on the trunking needs to be.

- Secondly, when I am passing through walls (brick) as I go from the ceiling from one room to another, what are your recommendations on making this entry? I have an SDS drill but thought that it may not work right in the corner of the ceiling and wall.

- Thirdly, whilst the smoke detectors need to be daisy chained with the 3 core and earth cable, how do I install an Aico Fire Control Switch? Remote Control Alarm Switch 230v Mains - https://www.cef.co.uk/catalogue/products/1148678-remote-control-alarm-switch-230v-mains?gclid=16b5a446064114559754c4ddd79e91a2&gclsrc=3p.ds&msclkid=16b5a446064114559754c4ddd79e91a2

Is this just like another smoke detector in the sense that it should be included in the daisy chain i.e. one cable in and one out to the next detector?


Thanks in advance

 

[Mike Johnson]

I am sorry you are pushed for time, but you need to do a little homework yourself: https://04646a9cf351cc0d3888-b8b406...49ac64a455d7d50c7c919cd8e8e8d5.pdf?1570024787

 

[Neptune]

Thanks guys. I’ve read the install doc but don’t see any guidance on the below.


When slotting the trunking into the smoke detector, does some of the top and bottom section of the trunking disappear into the detectors base? I am trying to determine how neat my cut on the trunking needs to be.

- Secondly, when I am passing through walls (brick) as I go from the ceiling from one room to another, what are your recommendations on making this entry? I have an SDS drill but thought that it may not work right in the corner of the ceiling and wall.

I would appreciate your advice on this please.

 

[Mike Johnson]

Can't get the quote up.

 

[Mike Johnson]

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

Challenge the Local Authority and ask where in the Regulations it says that wireless interlinked systems are unacceptable, which council is this? if they insist ask for it in writing.

Radio links are acceptable by most all authorities, what they are probably saying is the power to the alarms are to be from the mains to charge the non replaceable batteries, in this case the alarms can be powered from any lighting rose or power within the ceiling without the need for trunking or drilling walls.

 

[nicebutdim]

- Thirdly, whilst the smoke detectors need to be daisy chained with the 3 core and earth cable, how do I install an Aico Fire Control Switch? Remote Control Alarm Switch 230v Mains - https://www.cef.co.uk/catalogue/products/1148678-remote-control-alarm-switch-230v-mains?gclid=16b5a446064114559754c4ddd79e91a2&gclsrc=3p.ds&msclkid=16b5a446064114559754c4ddd79e91a2

Is this just like another smoke detector in the sense that it should be included in the daisy chain i.e. one cable in and one out to the next detector?

Yes - control switch fitted as though it were another head.

 

[Neptune]

Challenge the Local Authority and ask where in the Regulations it says that wireless interlinked systems are unacceptable, which council is this? if they insist ask for it in writing.

Radio links are acceptable by most all authorities, what they are probably saying is the power to the alarms are to be from the mains to charge the non replaceable batteries, in this case the alarms can be powered from any lighting rose or power within the ceiling without the need for trunking or drilling walls.

I can query again but the lady from council was categoric. The interlink should be cables and not wireless.

 

[littlespark]

Speak to someone else at the council (again, which council? Your county location)

I’ve had a recent customer, who on one hand was being told he needed a mains interconnected heat alarm in his kitchen and a carbon dioxide monitor in his bedroom...

And a sensible council official saying the kitchen wasn’t a recent change so didn’t need it.... and a carbon dioxide monitor in a 200 year old house with single glazed windows was totally pointless.

(carbon dioxide monitors being installed in new build passive homes where there is no ventilation. Different to carbon monoxide alarms)