- UNDERGROUND POWER DISTRIBUTICN The underground primary distribution consisted of three-conductor, 5000 volt, rubber insulated, non-metallic sheathed, type RJ cable suitable for direct burial. This cable was laid on a bed of fine sand, covered by a layer of sand,and topped with 2 inch by 6 inch creosotetreated planks, Trenches were backfilled and trench depths varied from three to four feet, Taps to primary cables were made in the trench and extended to buildings or to transformers on concrete pads adjacent to buildings. The underground secondary distribution consisted of two, three, or four conductor, 600 volt, rmabber insulated, nonmetallic sheathed cable suitable for direct burial. These cables were not laid in sand, and plank covers were not installed, See Figures 5.16-1, 5.16-2, and 5.16-3 for schematic power-distribution drawings for Runit, The Aomon Group, and Engebi The following is a list of major items included in the underground distribution system: 5 kv direct burial cable 600 v direct burial cable 5 kw submarine power cable 56,270 feet 45,850 feet 27,500 feet MAINTENANCE It was known that steel, although galvanized, deteriorates rapidly in the climatic conditions prevalent at Eniwetok and a careful investigation was made of possible materials for guy wires other than galvanized steel. As a result, the conclusion was reached that there was no other material econamically feasible, and galvanized steel guy wires were specified, knowing that there would be contimial maintenance and replacement of guy wires required. Some oxidation occurred on the overhead bare copper lines, This oxidation is a surface phenomena and experience has shown that this does not result in an unreasonable maintenance problem. 5-234