Alarms - Mains Wired, Interconnected

[nero44]

Hello Everyone,

FYI >> ca1900 period property, owner occupied, so regs/alarms in theory not required.

Regardless, I am looking to improve on this for my family's safety. My property currently has one heat detector in the loft (where I also store my PV batteries) and one interlinked smoke alarm in the closest hallway. They are fed by a nearby lighting circuit, which is in constant use. This has been installed by an MCS registered electrician. I also have a CM detector next to my gas boiler. The previous owner stated they had 3 battery operated smoke alarms, but I could only find one! So either they made a mistake or they had some non wall/ceiling mounted ones they took with them... no idea.

Anyway, I am looking to add one to each floor (+extra heat alarm in the kitchen) and have mapped some potential wiring routes. Hardwiring them all together is going to take some effort, but potentially doable without massive re-decorating. I am now facing two options:

1. If wiring permits, wire all onto the same existing lighting circuit using 3 core+cpc, which would also allow for hardwirde interconnection. Seems like the most stable/safe/cleanest route but most work to find routes across 3 floors. All linked to a frequently used lighting circuit so any circuit failures will be noted quickly.
2. Mains wire from separate lighting circuit of each floor and interlink all wirelessly. Probably a little less work, less disruptive, but might need to spend more and get a new set of alarms that can do wireless interlinks. Are these wireless interconnected ones reliable? Any downsides of "spreading" smoke alarms over different circuits?

Which one would you choose?

 

[Murdochcat]

If they are on seperate circuits they have to be linked by RF

The only make worth fitting is Aico as they are very reliable and have great support.

 

[JohnW2]

If they are on seperate circuits they have to be linked by RF

From what he writes, it would appear that the OP already knows that, and is asking about the pros and cons of hardwired and wireless/'RF' inter-connection.

Personally, in any context, I tend to prefer hard-wired connections (between anything) to 'wireless ones (unless hardwiring is impractical - e.g. in relation to something which 'moves around') but, as the OP acknowledges, that usually requires a bit more (and probably more disruptive) installation work. What are your views?

 

[trojanhawrs]

We would all prefer hardwired but it might be cheaper to get fully wireless if you can't hardwire the interlinks. The batteries are good for 10 years which is when they recommend to replace all fire alarms mains or otherwise. Mains will be cheapest but you'll pay in sweat and tears.

 

[nero44]

Thanks all. That's good enough for me to at least attempt to hardwire. Hallways and floors still have old carpet and I had them open already once for another issue.

Will have a go a this in a couple of weeks' time, too many unfinished other projects need attention first...

 

[nero44]

Follow-up question on this. What is your view of having a heat alarm in an unconverted damp victorian cellar? My cellar is half-height and looks like this. But it houses the consumer unit. (n.b. the picture is old and I have a new modern CU there now). I always thought the guidline is at least one per floor with habitual rooms, whereas my cellar is certainly not habitual, but has the CU.

 

[Murdochcat]

Why a heat alarm? I would put a normal alarm down there linked to the rest of the system

 

[nero44]

Same reasoning why my sparky put a heat alarm in my loft where I have my battery and inverter. Dusty environment more often then not can give false alarms, so it's common to use heat alarm in such environments according to them.

If I can realise the planned cabling routes for the other ones, then one in the cellar would be really easy. just wondering if it's necessary at all.

 

[JohnW2]

Why a heat alarm? I would put a normal alarm down there linked to the rest of the system

I was going to ask the same question but, as the OP has said, there is an argument that optical alarms may not be ideal in very dusty environments, if that's what his cellar is.

 

[Murdochcat]

I was going to ask the same question but, as the OP has said, there is an argument that optical alarms may not be ideal in very dusty environments, if that's what his cellar is.

If the OP was planning to fit Aico I would suggest he reached out to their tech support guys

 

[Murdochcat]

From what he writes, it would appear that the OP already knows that, and is asking about the pros and cons of hardwired and wireless/'RF' inter-connection.

Personally, in any context, I tend to prefer hard-wired connections (between anything) to 'wireless ones (unless hardwiring is impractical - e.g. in relation to something which 'moves around') but, as the OP acknowledges, that usually requires a bit more (and probably more disruptive) installation work. What are your views?

Ideally a totally hard wired set up is preferred , powered from one of the lighting circuits

 

[nero44]

Yes Aico, I already have two of them, so was planning to get a couple more and wire them up together. My question was more on whether it's worthwhile to fit one in the cellar and if this is standard practice. I guess certainly won't hurt (other than a little more electricity consumption)...as for location, I presume I can just attach it to one of the joist somewhat close to the CU?

 

[Murdochcat]

Yes Aico, I already have two of them, so was planning to get a couple more and wire them up together. My question was more on whether it's worthwhile to fit one in the cellar and if this is standard practice. I guess certainly won't hurt (other than a little more electricity consumption)...as for location, I presume I can just attach it to one of the joist somewhat close to the CU?

You could have one in every room, the cellar, the loft and your garage if you wanted to.

I put one in our garage as I often charge tools in there, and one in our kids TV room so we have 5 in total, all hard wired - you can never be too safe

 

[JohnW2]

I put one in our garage as I often charge tools in there, and one in our kids TV room so we have 5 in total, all hard wired - you can never be too safe

Yes, it's impossible to be 'too safe'. However, if one is not careful enough when choosing which type of sensor to put in which location, one could possibly end up being 'driven mad'

... and, of course, to be serious, the danger of people getting driven mad is that some may respond by removing or disabling the alarms.

 

[Murdochcat]

Yes, it's impossible to be 'too safe'. However, if one is not careful enough when choosing which type of sensor to put in which location, one could possibly end up being 'driven mad'

... and, of course, to be serious, the danger of people getting driven mad is that some may respond by removing or disabling the alarms.

Well, I always like to put a heat alarm in a kitchen but on a recent job the customer said she didn’t want one and the BCO said she didn’t need to have one - which I thought was odd because he normally said they had to be fitted