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.

 

[littlespark]

First check there isn’t a live and neutral at the light... older houses, this is where it was. Neutrals at switches is a fairly new thing.

from the light, you only need a live, neutral and earth to first smoke, then a 3 core and earth in a daisy chain to each other detector in turn. Live neutral earth and interconnecting cable.

some manufacturers offer 10 yr lithium detectors with radio signal interlink, for when you don’t want to disturb decoration,
Or mains with a radio module. Or the house can be a mix of wired and wireless...

 

[Strima]

AICO do a very good wireless range.

 

[loz2754]

AICO do a very good wireless range.

Also AICO bases have a cut out that accepts mini trunking.

 

[Dartlec]

One thing you will need to be careful of is the requirement for protection against premature collapse in the recent regulations.

Plastic trunking along a ceiling or high up on a wall could be liable to collapse during a fire, and cause potential risks to the tenants getting out, or fire fighters who are dealing with the situation.

There are metal clips available that fit inside plastic trunking to support the cabling in the event of the worst. I believe best practise is to fix them not with plastic rawl plugs, but with entirely metal fittings - you may be able to get metal screws into the joists for example.

In a standard hallway you may only need one or two of the clips on a run of trunking, with other fixings being normal rawl plugs if necessary

 

[littlespark]

^ another reason to go with battery radiolink versions.

 

[Neptune]

Thanks for all the responses. Really appreciate it.
How about the trunking detail when it connects to the light pendant?

Also, is there a certain type/profile of trunking you recommend? I noted the point re. metal clips.

 

[westward10]

You can get ceiling rose adapters for mini trunking it will drop the rose a bit but gives a neat solution.

Mini Trunking Ceiling Rose Adaptor White (Sold in 1's)

For use with mini trunking MMT1 and MMT2

www.cef.co.uk

As for internal metal fixings most are designed for 25 × 16 and upwards but if using 16 × 16 there are these although I have never tried them.

D-Line Safe-D Mini Trunking Spring Clips

Secure single cables with an outer diameter of up to 7mm by using these D-Line Safe-D spring clips. Suitable for use in PVC micro trunking or for direct-to-surface fitting – when secured with D-Fixings, the springs can hold cables in-situ at 970°C for up to two hours.Safe-D springs use...

www.toolstation.com

 

[MJPD29]

I would look into aico wireless base ones as well, nothing I hate more than mini trunking. Although sometimes it has its uses, I find it looks very amateur.

 

[i=p/u]

Also AICO bases have a cut out that accepts mini trunking.

Wash ur mouth out, yuck.

 

[loz2754]

Wash ur mouth out, yuck.

The OP has stated that he intends to use trunking to supply power to the smoke alarms from either a light or a switch, regardless of whether they're interconnected wirelessly, they still need power.

 

[pirate]

TBF, they can all be battery and radio-linked, at least the Aico ones can. I generally used to install the hall smoke as a wired, from a light, with a 10 year battery, and the rest just 10 year battery, radio linked. No mains wired for me now...why bother?
Unless your local BC have other ideas...
Better to have something that works, IMHO.

 

[loz2754]

TBF, they can all be battery and radio-linked, at least the Aico ones can. I generally used to install the hall smoke as a wired, from a light, with a 10 year battery, and the rest just 10 year battery, radio linked. No mains wired for me now...why bother?
Unless your local BC have other ideas...
Better to have something that works, IMHO.

This would be a Grade F system according to BS5839:6. You're quite correct in saying that some local building control/councils will not accept anything other than Grade D (mains interlinked).

However it should be ok in the private rented sector, as the actual legislation from October 2015 doesn't require mains OR interlinking, just smoke alarms on each floor.

 

[brianmoooore]

However it should be ok in the private rented sector, as the actual legislation from October 2015 doesn't require mains OR interlinking, just smoke alarms on each floor.

Another "C2 or C3" future thread in the making?

 

[loz2754]

Another "C2 or C3" future thread in the making?

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

 

[brianmoooore]

Not yet.

 

[loz2754]

Not yet.

I give your comment a C3. ?

 

[pirate]

To clarify, I was commenting from a Scottish perspective.

 

[loz2754]

To clarify, I was commenting from a Scottish perspective.

Ah. Different set of riddles rules.

 

[Neptune]

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]

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]

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]

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]

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.

 

[Neptune]

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]

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]

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]

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]

Is 1.5mm 3 core and earth required for this?

You'll need 3 core for the link.

 

[brianmoooore]

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.

 

[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)

 

[Mike Johnson]

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

Perhaps talk to your local Fire Brigade prevention officer.

 

[Mike Johnson]

Should say "Fire Brigade, Fire Prevention officer"

 

[Mike Johnson]

- 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

More modern radio linked test switch: RadioLINK Alarm Controller - https://www.tlc-direct.co.uk/Products/EI450.html?

 

[Lister1987]

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

Request to see the evidence to support Thier stance. If they can't provide it, ignore it, if they can't find it to show you then they won't find it to hit you with either.

 

[baldelectrician]

We install Aico alarms only

The mains bases have a bit that snaps out to allow YT2 mini trunking.

Also- BS5839 Pt6 has been updated to allow 10 year sealed radio linked detectors.
As others have said - ask the council officer for documentation requiring the mains only ones

The 10 year ones do work and last- the Aico ones even bounce the signal from one detector to others in a 'mesh' type of system. This way if the alarming unit is almost out of range of the furthest unit the ones on the way pass the alarm signal on (as well as the silence signal)