Interconnected smoke alarms

Hi,

I am looking to invest in a Texecom Premier system and also want 3 interconnected smoke alarms (2 regular units on ground and first floor, heat sensor in kitchen).
I understand that they can be connected into my Texecom system and wanted some advice on this please:

- do each of these connect to their own zone or can it only take a single zone
- can I have a specific alert generated by telephone if one of these zones is activated
- how do I cable these? Do I just need alarm cable going back to the control panel or does it also require separate power/interlink cable

Sorry for all the questions but I am hoping that someone has already done this and can point me in the correct direction.

Thanks in advance

2 options , 3 Texecom smoke detectors and sounders
Or 240v interlink smokes with relay bases , wired to separate zones via alarm cable

If I went for the 3 Texecom smoke detectors and sounders, do they all need to be wired into a single zone and do they need any cables other than the alarm cable going back to the panel?

Personally I prefer to keep what are essentially 'safety critical' and 'convenience' devices completely separate. If your Texecom alarm fails for some reason then that's unfortunate, though it's unlikely to cost you your life. However, if your smoke alarms don't activate and wake you up because of a fire at 2am then this is more serious.

In a full Grade A or Grade B fire alarm system everything is centrally powered and monitored, and connected to individual sensors and sounders using fireproof cable. If there is a fire then you can be pretty sure that the alarm system is going to activate. If individual sensors fail the fire panel will detect this pretty quickly and alert that this is the case. Fire panels are also pretty much fail-safe and will carry out their own internal self-tests to make sure that any problems are quickly identified.

Sensors like those from Texecom and Menvier are great, but are centrally powered, and have no inbuilt sounder. If the power supply fails, or the Texecom panel fails then you instantly lose all protection. I've avoided installing this type of detectors for exactly this reason. Instead I opted for a set of Aico self-contained mains powered interlinked alarms with a ei128r relay module. If the alarms sound then the relay module triggers a zone on the alarm. If the power fails or the alarm processor has a ill-timed funny five minutes then the individual alarms can work independently, powered by their own internal 9v battery. You don't have quite the same 'convenience' of knowing which particular smoke detector operated, though if you're in the building this is easy to identify - and if you're not then this information still doesn't confirm whether its a false alarm or not.

You don't have quite the same 'convenience' of knowing which particular smoke detector operated, though if you're in the building this is easy to identify - and if you're not then this information still doesn't confirm whether its a false alarm or not.

If the relay bases are wired individual to separate zones then you do know which one activated

sparkymarka said:

You don't have quite the same 'convenience' of knowing which particular smoke detector operated, though if you're in the building this is easy to identify - and if you're not then this information still doesn't confirm whether its a false alarm or not.

If the relay bases are wired individual to separate zones then you do know which one activated

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Agreed. With the addition of a ComIP or ComWiFi and the Texecom app you can be remotely notified that a detector operated. If you have everything on separate zones and more than one goes off then it sounds like your house is on fire!

Ideally I'd like to have each detector on separate zones, and retain the Aico interlink - so that all of the alarms in the house sound simultaneously, and have panel notify me of which particular detector was triggered. However, there is only a single interlink terminal. Even with a relay base on each detector you've no way of knowing if the relay has been activated by the local detector activating, or by means of current back-feeding down the interconnect cable from a detector elsewhere in the house.

Short of putting diodes on each detector I can't think how to do this - and I'd rather not interfere with what is essentially a 'safety critical' system for the reasons above.

Thanks @ultomoat. That was very helpful.
If I have understood you correctly, you are suggesting an AICO interconnected system which can work independently of the Texecom system in the event that the panel fails. In this situation the smokes would work directly off the mains. If the mains failed, it has a backup battery and if all was working, it can send a message to the Texecom panel and trigger a zone. Have I understood this correctly?

Assuming yes to the above, I guess that I need to wire in the smokes as conventional mains powered interconnected devices and then also have alarm cable going to the panel?

Jupiter01 said:

If I have understood you correctly, you are suggesting an AICO interconnected system which can work independently of the Texecom system in the event that the panel fails. In this situation the smokes would work directly off the mains. If the mains failed, it has a backup battery and if all was working, it can send a message to the Texecom panel and trigger a zone. Have I understood this correctly? Assuming yes to the above, I guess that I need to wire in the smokes as conventional mains powered interconnected devices and then also have alarm cable going to the panel?

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Yes. I have a set of Aico mains powered smoke alarms, which each have a 9v PP3 battery inside them. The alarms are powered off the mains and if the mains fails they are powered off the internal battery. They are connected together with conventional 3 core and earth cable. If one alarm sounds then they all do. In theory if something should go wrong with the interlink (or a fire burns through the cable before any of the alarms detects it) then the alarms continue to work in isolation. This is standard stuff that all new-build houses are required to have now.

Separately I bought a Aico EI128R relay base. This connects into the interconnect cable in the same way as the smoke alarms themselves do. It contains a set of relay contacts which close when any of the smoke alarms sound. I've then got my alarm connected to this relay, which triggers a zone on the panel. If the smoke alarms go off then the relay switches, changes the state of the zone - and it activates both the internal alarm sounders, and separately sends SMS messages to warn that something is amiss. I'm using a Honeywell alarm panel, though you can do exactly the same with Texecom and ComIP or ComWiFi. The relay base is intended for warden call systems in sheltered housing etc, though does a very good job here.

The advantage of this set up is that everything remains self-contained and isolated from other components. If the Texecom alarm itself bursts into flames, or the cable linking the detectors/relay/alarm etc is compromised then hopefully at least one of the smoke alarms remains operational and wakes you up before the house burns down. The problem with the Texecom etc detectors is that there is too much to go wrong in a very small number of places - such single points of failure on safety critical systems are dangerous.

If you go this route ensure that you keep the mains and alarm cables well away from each other in the AI128R relay. I seem to remember the instructions recommending that ELV (ie 12v) cables are 'double-insulated' - ie insulation over the existing insulation to remove the risk of 12v and 240v wiring coming into contact with each other.

I found Edwardes by far the cheapest for Aico bits. If you can find cheaper let me know - I need to buy another detector for the garage at some point. See the Aico website for a handy 'what should I fit where?' guide. Hint: Ionisation detectors anywhere near the kitchen are the reason for false alarms from toast etc.

Aico: https://www.edwardes.co.uk/en/products/aico-ei141rc-240v-ionisation-smoke-alarm---base
Relay base: https://www.edwardes.co.uk/en/products/aico-ei128r-relay-mounting-base-for-140-160-alarm

As above, the disadvantage of this set up is that unless you're at home you cannot tell which alarm caused the system to trigger - but you can phone a friendly neighbour and say "Hi Bob, I think my smoke alarms are going off, would you mind going and checking that there isn't smoke coming out of the windows?"

One more thing. You cannot mix and match brands and/or models of interconnected alarms. If you go the Aico route then everything must be from Aico (I can't remember if you can mix 140 and 160 devices). You certainly can't start adding Kidde and similar alarms - it won't work and will most probably damage them.

I thought you only need one relay base ? End of line then your LV cable back to the panel.
And it's 230v now

Can I please confirm that I will need a 1.5mm twin and earth cable from the consumer unit to feed the first alarm and from there, there will be a 3 core and earth cable going from that alarm to the next and then from there to the next and so on, until all of the alarms are conected in a sequence.

Can you please confirm that the above is correct.

Finally, can you please clarify how the relay base fits into the above. I understand that my alarm cable will connect to the relay base and then to the alarm panel but I’m uncertain on how the relay base is accommodated by the above setup.

Yes two core t&e to first alarm then a 3 core & earth to each of the others.
On my last job I fitted the relay base onto the last alarm,fit the base first then the smoke just screws into that

oh ok. That suggests that there is no wiring between the relay base and the smoke alarm? It just screws on?

Hi,

Apologies for the delay in replying. Yes. The first alarm in the chain is powered using normal 1mm 2 core and earth cable. Subsequent alarms are chained off this using three core and earth cable.

You have two choices with the relay. As Phil suggested you could fit one of the alarms to it (the alarms mount on top of the relay enclosure), though this does mean that the alarm will be about an inch lower than normal.

Alternatively have a run of 3 core and earth explicitly feeding the relay, connected off the closest alarm. Aico manufacture a lid for the purpose which is on the Edwardes website that I linked to. Personally I have the relay in the garage and a cable through the wall to the smoke alarm in the hallway.

In terms of powering them you can either power them from a dedicated 6A circuit breaker if one already exists, or power them from the downstairs lighting circuit. The regs (both electrical and building) allow either. The advantage if powering the smoke alarms from the lighting circuit is that you'll notice if the circuit breaker trips pretty quickly. There is a risk that if a dedicated breaker tripped then it wouldn't be noticed immediately - though the 9v batteries would kick in at this point.

If you go the lighting circuit route then building regs suggest that there should be a means of isolating the smoke alarms without affecting the lights, though I've never seen this done. A clearly labelled 20A switch would suffice.

Jupiter01 said:

oh ok. That suggests that there is no wiring between the relay base and the smoke alarm? It just screws on?

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In this configuration there are still wires between the two (albeit a couple of inches long). These aren't supplied with the alarm or relay - as with the other devices 1mm 3 core and earth would be fine.

Thanks @ultomoat.
That was very helpful. I will buy the cap and situate the rely base next to my control panel.