If a dual-voltage generator is installed on an OSV -
(a) The neutral of the dual-voltage system must be solidly grounded at the switchboard's neutral bus and be accessible for checking the insulation resistance of the generator; and
(b) Ground detection must be provided that -
(1) For an alternating-current system, complies with § 111.05-27 of this chapter; and
(2) For a direct-current system, complies with § 111.05-29 of this chapter.