Slaved power control 'current transformer'

["Stuart Meier" <stuartm2007@xxxxxxxxx>]

I want to detect power starting to flow in one circuit, to trigger a
second.
EG, if any power is drawn by the electric cooker, the hood fan starts.
Direct connection is out for various reasons - the detection has to be
electrically isolated.

It requires a so 'called current transformer', but I can't find a supply of
one, apart from in those extension leads with a 'master switch'. I guess
could tear the guts out of one, but a supplier must exist. I could build
one
from scratch (op amps etc), but want to avoid the hastle.

Any suggestions?

Stuart