The neutral of each grounded generation and distribution system must:

1. (a) Be grounded at the generator switchboard, except the neutral of an emergency power generation system must be grounded with:

   1. (1) No direct ground connection at the emergency switchboard;
   2. (2) The neutral bus permanently connected to the neutral bus on the main switchboard; and
   3. (3) No switch, circuit breaker, or fuse in the neutral conductor of the bus-tie feeder connecting the emergency switchboard to the main switchboard; and
2. (b) Have the ground connection accessible for checking the insulation resistance of the generator to ground before the generator is connected to the bus.