"thankyousam" wrote in message
oups.com...
I'm adding a couple of mains fed smoke alarms to my lighting circuit.
The first one is simple enough as there is a run of cable above the
location in the hallway. I'm intending to "loop in" the smoke alarm as
you would with a ceiling rose - allbeit without a switch

I'm not sure how to build the second alarm (upstairs) into the circuit.
Can I simply spur it off the downstairs smoke alarm using three+earth
(for the interconnect)? Or do I need to "loop in" the second alarm as
well? I've tried to illustrate both. I can't see why the first method
would be a problem, just wanted to check.

Spurred: ( = T&E, ||| 3&E Interconnect)

Rose ==== Smoke Alarm 1 ==== Rose
|||
|||
Smoke Alarm 2

Full Loop In: ( = T&E, =~= 3&E Interconnect)

Rose ==== Smoke Alarm 1 =~=~= Smoke Alarm 2 ==== Rose


You can just spur it off the first alarm.