Keeping the main breaker from tripping

[Alan Anderson]

Originally Posted by GeeTwo

For anyone trying to implement this --the voltage produced by the ring (which merely needs to be conductive, not ferrous) is directly related to the RATE OF CHANGE of the current....

That might be true if using an inductive sensor, but a Hall effect transducer responds to magnetic flux directly. The ring is not acting as a transformer element, but as a flux concentrator, and does need to be ferrous.