Bypassing a smoke alarm feed on lighting circuit

[Alarm Engineer]

Hi,

I recently removed a redundant mains smoke detector which feeds other now redundant smoke detectors along with a couple of lights too. One of these I recently removed and did not join the two wires together therefore as a result lost some lights!!!

I have a T&E incoming with 240v on it and another cable with a Brown, Black & Grey which must be the outgoing to the rest of the circuit. Old smokes had a trigger line to sound other detectors I believe. This one could well have been 1st on the circuit as its next to consumer unit .

What do I need to connect to what to get the circuit working again? Or is it a matter of tracing the colours around?

Can anyone shed some light....

Thank you.

 

[Taylortwocities]

You need to identify which of the three wires (brown, black grey) is the trigger wire, which is neutral and which is line. You should know that from when you disconnected the smoke! Or look at another smoke, or use the two-probe voltage tester that any self-respecting service engineer carries.

Then connect the earth line and neutrals together inside a proper enclosure, leaving the trigger wire separate in an insulated connector.

And strip back the brown and blue conductors properly, jamming the terminal screws through the insulation is a certain way to create problems.

How come the alarms are redundant? Surely they are still required?

 

[Alarm Engineer]

Ok, thank you.

All mains smokes removed and replaced for intruder alarm smoke detectors which provide remote monitoring & look
better etc..

I have removed all others and put in proper enclosures as suggested.

The wire pictured was placed in choc block until i worked out the connections.

The Brown/Black/Grey is outgoing so what would be best way to work out what colour is for what? I take it I no longer need the switch line and only need the L & N ?

 

[Alarm Engineer]

Sorted now, it was Grey & Brown that I needed.

 

[Taylortwocities]

And earth

 

[deadshort]

Sorted now, it was Grey & Brown that I needed.

Well, i would use black for neutral on 3 core , is that wrong ?

DS

 

[flameport]

black for neutral on 3 core

Certain organisations suggested that black should not be used for neutral to differentiate between old and new wiring colours, black being neutral in the past on red/black wiring.
Therefore brown line, grey neutral, black earth, with the appropriate coloured sleeves for neutral and earth.
However there is nothing to prevent black being used as a neutral, but it would require a blue sleeve, just as grey would require a green/yellow sleeve if it was used as earth.

Other methods of identification are available, particularly when cables contain wires of all the same colour.

 

[Iggifer]

Aico bases 'somewhat' suggest you should use the black for switch. The IC is black, and tbh, the way their bases are laid out you'd be silly to use anything else, it's just the easiest way