Each battery charger enclosure must meet § 111.01-9 . Additionally, each charger must be suitable for the size and type of battery installation that it serves. Chargers incorporating grounded autotransformers must not be used. Except for converters, chargers with a voltage exceeding 20 percent of the line voltage must be provided with automatic protection against reversal of current.
46 C.F.R. §111.15-30