Mains powered smoke alarms

[Spark1979]

Well I know interlink ain't 240v as it doesn't have to be marked brown if it's the black core on a 3 core as its not 'live' but low voltage

 

[electric will]

Wouldn't have to be marked anyway, it's classed as a control wire like central heating, had this discussion with assessor a while ago. Then as the conversion went he didn't know if it'd be mains or low voltage either.

 

[grantr37]

that type of opto-isolator won't stop mains voltage, it will pop....generally a 4N25 4 pin.....older style smoke detectors used a 5volt TTL AND to give an output high signal (condition) connected to the same track on the board as the test button.....connecting AC mains to the signal pin of the base on any unit by mistake will fry all the detectors on that chain, resulting in fault chirping and a burning PCB smell.....and the recycling facility (ionising type must be legally recycled and not binned due to radio-metals contained inside) new optical sensor alarms are non-radio emitting and can be binned/recycled as normal, these are phasing out the ionising scintillation detector hardware...