Wiring new smoke alarm

[flickaz]

We are trying to replace very old, outdated smoke alarms. When we have tried to use the existing connection the new alarms won't fit. This is the wiring we currently have:

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The new alarm is a FireAngel sw1-R with the following cables:

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What goes with what?

[Someone-Else]

Its quite "normal" to have to rewire smoke alarms as they have different connection methods.
You said smoke alarms, as in more than one, I suggest you change them all at the same time, next question, what do the other alarm connections look like?

Smoke alarms only have 3 wires, Live, neutral and interlink, so it is fairly easy to do, but you do have to get it right first time, hence my asking about the others.

[flickaz]

We have 2: top and bottom of stairs. We have bought 2 the same to replace a matching pair which both have the same wiring as pictured. The house was built late 90s and now we've got the existing pair down we can see they say 'replace by 2005' so they're definitely very old!

[Someone-Else]

both have the same wiring as pictured

That does not sound right, are you sure there is not another cable "hiding" behind one of them?
Also (This is going to sound silly) why did you decide to change them?

[flickaz]

We didn't go exploring much beyond what you can see. The 3 cables seemed to come out of one flex. We changed them because the downstairs one suddenly started beeping for no reason. We took it down to clean it and then realised the age.

[Someone-Else]

The 3 cables seemed to come out of one flex.

and the other alarm please.

I am thinking there is something else wrong, that is why I need to see both.

[flickaz]

They're both the same except the downstairs one came out of a bigger hole.

[Someone-Else]

The 3 cables seemed to come out of one flex.

and the other alarm please.

I am thinking there is something else wrong, that is why I need to see both.