For context, an isolated type single phase generator (no earth stake or neutral-earth link) had a residual current device connected to it and then a fault between active and earth was placed on the generator. The RCD did not trip, and I worked out why it didn't based on the single phase generator schematic below. What happens in a three phase system?
With no Earth - Neutral bond. If there is a connection (fault) between earth and active, then the active conductor will be bonded to earth (0V) and the Neutral line will oscillate between +/- 230 v.
What happens now if there is a connection (fault) between earth and one of the lines?
- A dead short and the Circuit Breakers trip?
- The line is bonded to zero volts and the other two lines and neutral oscillate around it?