Hi, I have installed two interlinked fire alarms as part of a renovation
project. However they are not linked at present just have two white cables,
coming from each one. Is it ok to take a single core out of some 1mm/1.5mm2
cable I have laying around as I cant seem to find a single core that's not
red or black, and I have three way cable with a different colour core which
I could use.

Thanks
John