why do smokes randomly go off??

[accordfire]

thanks for pointing out the colours used today??????<<<<>>>>....the yellow that i am talking about comes on the smoke alarm it has a brown (phase) blue (neutral) yellow (monitoring cable) what i was trying to say he may have connected the yellow as an earth so when you plug this into the smoke alarm it creates an inbalance tripping your rcd.

I see. That wasn't clear in your first post.

That said, I'm not aware of many smoke detector which have flying tails in them any longer. What brand of detector are you using?

And in principle, you're totally right - connecting an interconnect signal to earth will trip an RCD.