Discuss Strange 3 cables in old Fire Smoke Alarm in the UK Electrical Forum area at ElectriciansForums.net

Reaction score
2
I'm about to order this wired smoke alarm system as it can network but I just went to see how my existing fire alarms are hooked up and there appear to be three wires? What/how would I connect the new one when it arrives? This old one isn't linked tot eh other one on the landing as I know for sure it only goes off downstairs.

This is the old one:
 

Attachments

  • IMG_4268.jpg
    298.6 KB · Views: 50
If it has been done properly then you will find a backbox behind the mounting plate which encloses the single insulated conductors you can see there and whatever has been used to connect them to the installed cables.

Or you may find that there is a mess of connector blocks shoved into the ceiling void joining those wires to the installed cables.
 
If it has been done properly then you will find a backbox behind the mounting plate which encloses the single insulated conductors you can see there and whatever has been used to connect them to the installed cables.

Or you may find that there is a mess of connector blocks shoved into the ceiling void joining those wires to the installed cables.
This is all I can see?

And this is what I am swapping it out for hopefully

Deal: FireAngel Pro Connected Smart Smoke Alarm, Mains Powered with Wireless Interlink and 10 Year Life Back-Up Battery, FP1640W2-R , White https://amzn.eu/d/5QTCKeC
 

Attachments

  • IMG_4276.jpeg
    252 KB · Views: 42
The preferred make of alarms by most electricians is Aico, more reliable than most, I use the 3000 series as they do not have a flashing red light, just a steady green to indicate they are working, ten year battery life when mains connected and radio link to any others.
 
This is all I can see?
Very common on some newer houses.
If it won’t gently pull through to reveal the grey outer sleeved cable then the new one can’t be fitted in a compliant way.

The proper solution is to rewire it and remove the old.
The next best is to fit radio link units taking a new cable from a nearby light.
The last resort option is to make use of that wiring and some testing is needed to do that.
 
Doesn’t look like there’s a back box there. I think I can see the pinky coloured insulation in the ceiling. There should be, just as an enclosure for the joint.

The one pictured appears to be the first on a line. There’s a brown/blue twin and earth cable supplying the circuit, and a brown/black/ grey 3core and earth going to the next detector on the circuit.

The brown and blue are mains voltage 230v. Please isolate the circuit before proceeding!

The white cable that connects to black of the house wiring is just a signal wire that tells each detector to go off if one is sounding.

You can’t mix and match different makes of detector.
 
This is all I can see?

As I said above, a mess of connector blocks shoved into the ceiling void.

This is not compliant and should never have been done like this.

A back box should have been cut into the ceiling to enclose the joint and the exposed single insulated conductors.
 
Last edited by a moderator:
The proper solution is to rewire it and remove the old.
The next best is to fit radio link units taking a new cable from a nearby light.
The last resort option is to make use of that wiring and some testing is needed to do that.

Why do you say using the existing wiring is a last resort? I may have missed something but that looks to be modern brown and blue T&E/3C&E
 
Why do you say using the existing wiring is a last resort? I may have missed something but that looks to be modern brown and blue T&E/3C&E
It was me that missed something. Quite often you can’t actually get to the cable. But I agree that in this case it looks viable to simple pull it through.
 
I have seven Aico alarms in the house and in four in sheds in the garden and a barn over 10m away all radio interlinked, the test pad in the kitchen tells me witch one set the others off, information from each can be downloaded to an app and printed out, go the Aico web site, you will not get a better self install system.
 

Reply to Strange 3 cables in old Fire Smoke Alarm in the UK Electrical Forum area at ElectriciansForums.net

Similar Threads

I've asked a similar question before I think and we came to the conclusion that apart from new houses and HMO's etc there aren't any rules about...
Replies
3
Views
306
any BS 5839 experts know whether CO alarms should be connected to the smoke/heat alarm system ? after completing an efixx CPD it seems they should...
Replies
10
Views
1K
Hi All, Please may I ask if light fixtures must now always be fitted by an electrician? also for domestic homes, is it okay for there to be a...
Replies
4
Views
779
I'm about to start first fixing this fire alarm in the industrial unit we are wiring, at the moment its totally empty and eventually will have a...
Replies
5
Views
847
I'm installing mag-locks and fire door hold-open magnets at the moment and I'm wondering if any of the cable should be fire performance cable...
Replies
1
Views
622

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock