So what your saying is, the breaker (and I'm not really sure which one) is fine if turned on with no load and then loaded, but fails in the neutral pole if turned on with a load connected?
Relays can do this, which is why their contact material has to be chosen carefully for the application. With relays, the contacts bounce and spark, and the spark puts some oxide in between the contacts.
In reply to your two questions, if the current pulled by the "load" to earth is under 30mA/300mA they will not trip, and clearly there appears to be no amps overload. A bad neutral would be dragged up to phase voltage by the load.
[This message has been edited by gideonr (edited 05-23-2005).]
