111.05-17—Generation and distribution system grounding.
The neutral of each grounded generation and distribution system must:
(a)
Be grounded at the generator switchboard, except the neutral of an emergency power generation system must be grounded with:
(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
(b)
Have the ground connection accessible for checking the insulation resistance of the generator to ground before the generator is connected to the bus.