All building structures were grounded to a 3/4 inch by 8 foot ground rod driven into the coral adjacent to the building. Build- ing electrical equipment and service neutral conductor were grounded to a similar but separate rod. Power houses were similarly grounded. Individual rods were used for each piece or group of equipment. Transformer cases were grounded to ground rod at the base of the pole. Lightning arrestors for transformers were grounded to a similar but separate rod, Grounding was made difficult by the strata of ledge coral which often appeared near the surface and sometimes made blasting necessary, Installation of voltage regulators was not considered advisable because of the uncertainty as to what the final disposition of loads would be. Because of this and the large mumber of Jsers, each with specific voltage requirements, it was decided that they should supply their own regulators. OVERHEAD DISTRIBUTION For corner and transformer poles on overhead distribution, Class 2 Douglas fir poles treated full length with 8 pound creosote were used; similar Class 4 poles were used for distribution at more lightly loaded locations. Poles were 30 to 40 feet long and set approximately five feet into earth. Cross arms were untreated Douglas fir, 3-1/2 inches by 4-1/2 inches for power distribution and 3-1/4 inches by 4-1/4 inches for signal and telephone installations, ware was double-dipped galvanized. All pole-hard- Guy wires were 7/16 inch size, 7-strand, galvanized, 10,000 pound breaking strength. Insulators for the 2400 volt primary system were wet-process porcelain rated for 15 kw service, with a wet flashover rating of 60 kv. Both pin and suspension type were used. The high rated insulator was chosen to offset the effects of the high humidity and salt spray amd to assure a great degree of mechanical strength. Bare copper wire supported on 60 kv wet flashover insulators was used for primary overhead distribution of 2400 volts delta; and weatherproof wire was used for secondary services supported on secondary racks for 120/240 volt single-phase, 208 volt wye, and 240 volt delta distribution, The type of secom service depended on the kind of load served, The following list of major materials used in the overhead distribution indicates the magnitude of the work designed and installed. 5 kv Wire 600 v Wire Transformers Poles (All classes and lengths) Street lights 77,800 feet 172,050 feet 287 418 131 5-233