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:
     
    
        
        (1) 
         No direct ground connection at the emergency switchboard;
     
    
        
        (2) 
         The neutral bus permanently connected to the neutral bus on the main switchboard; and
     
    
        
        (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.