From a theoretical point of view you want the impedance of the PCBelarge's effective ground fault current path to be low enough to trip the breaker within a reasonable time.
If the 20A breaker is designed to be very forgiving to momentary surges in current while the 60A breaker so to speak is "trigger happy", you could get this counterintuitive result. The breaker manufacturers or their websites can no doubt tell.
[This message has been edited by C-H (edited 11-02-2005).]
[This message has been edited by C-H (edited 11-02-2005).]
