Hi
Firstly some generators have a ' phase and neutral ' output with a separate earthed chassis, the others have a ' phase and neutral ' output with either the earth connected to neutral or means to allow this connection.
The former will require a dedicated 3 terminal earth electrode tester to test the electrode while the latter can be tested with a loop tester.
For this test the MFT should be switched to Hi loop and the red and earth test leads should be connected.
Remember that if there is no neutral earth connection there will be no loop so no test. A simple dead continuity test between neutral and earth will comfirm this after safely locking out the generator.
Regards
Megger TSG
