ECN Forum Forums General Topics of the Trade General Discussion Area AFCI's Tripping upon Ground Fault Test

Hmm, I can see both sides of the argument for smoke detectors on their own circuit or combined with lights.

I suppose the ultimate system to get the best of both worlds would be an individual circuit for the detectors fed from a C/B with an integral alarm contact which sounds a separate buzzer if it trips, a little like the alarm fuses used in telephone exchanges.
That's probably getting carried away for residential though.

Brendan,
How did Cutler-Hammer come up with 30mA as the trip threshold for integral ground-fault protection in your AFCIs? Is is just coincidence that 30mA happens to be the standard ground-fault threshold for GFI in Europe now, or were your breakers designed with IEC specifications in mind as well as UL/ANSI?