only on a programmable earth fault relay not a fixed RCD or anything like that. It's not a value I'd expect anyone to normally need. 30mA, 100mA 300mA and then multiples of half amps are the go-to values, and I'd not trust it to discriminate with half an amp or an amp. In my experience, admittedly limited to earth fault discrimination between layers of distribution and final circuits, correctly isolating the minimum area with a fault is better done with time nested delays, rather than by increasing fault levels. Mike
