D.—l

Bombay-Waikino. —Lightning caused an outage of the Bombay-Kerepeehi section on 15th December, 1940, and of the Kerepeehi-Waikino section on 14th December, 1940. An outage of the whole line occurred on 9tli August, 1940, but nothing was found to account for the tripping. Waikino-Aongatete. —Outages were caused on 9th October, 14th December, and 15th and 20th March by lightning ; on Ist and 4th January due to cause unknown ; on 24th January by the failure of an insulator ; on 19th February by trouble on McLarens Falls system ; on 20th February by a scrub fire ; and on 7th, 12th, I4th, and 21st March by trouble on the Power Board system. Horahora-Matamata-Waihou.—Both sections tripped out during a thunderstorm on 18th March, 1941. Horahora-Hamilton. —Outages were caused by lightning on Ist October and 14th December. A tap line was run to Karapiro Substation in October. All Coutts connectors on the telephone-line have been removed and the joints remade and soldered. Hamilton-Huntly.—An outage was caused by the failure of an insulator on 13th December. Te Awamutu - Hangatiki. —Two outages occurred, one on 28th April, 1940, when the line was accidentally earthed, and the other on 7th November, 1940, during a thunderstorm. Ngongotaha-Edgecumbe.—A telephone-wire in the sulphur area broke, due to corrosion. Both wires were renewed in spans 158 to 162. Edgecumbe-Waiotahi.- -An outage occurred during a thunderstorm on 6th May. Arapuni-Ngongotaha and Waihou-Paeroa. —The usual patrol and maintenance duties were carried out on each line. (iii) 11 kV. Horahora-Hautapu. —An 11 kY. lightning-arrester broke down at Hautapu on 21st August, 1940. Hamilton-Frankton.—An outage was caused on 7th April, 1940, by a piece of fencing-wire being thrown over the line, and on 23rd November, 1940, and 31st December, 1940, by insulator failures on the 11 kY. change-over A.B.S. at the New Zealand Railway substation. Waikino-Waihi.—Corroded steelwork on towers was replaced by reconditioned parts taken from the dismantled Waiorongomai-Waikino 50 kV. tower-line. Grand Junction Tap. —The work of dismantling this line was completed in August. Arapuni Villa,ge. —Considerable time was spent on alterations to old service lines and dismantling of old poles. Ongarue-Manunui.—A set of lightning-arresters was installed at Taumarunui. (iv) General. Line-maintenance.—Routine work was carried out on the various lines according to schedule, including the live-line testing of insulators on JlO kV. and 50 kY. lines and the testing of poles by boring. Insulator Replacements. —The results of insulator testing or inspection are as follows :—

Twenty insulators were replaced under live-line conditions. In addition to the above replacements, four defective insulators on 11 kV. lines also were replaced. Pole Replacements. —Forty-seven defective poles were replaced during the year, the total being made up of eight 52 ft. poles on 110 kV. lines, one 38 ft. and two 42 ft. poles on 50 kV'. linos, four 35 ft. poles on 11 kV. lines, and one 52 ft., one 35 ft., and twenty-nine 25 ft. poles on telephone lines. Two 25 ft. poles broke off at the ground-line, and replacements of the balance were mainly on account of decayed heartwood. (d) TESTING. Routine tests wore made on meters, relays, instruments, &c., throughout the district, installation tests on new equipment at the various substations—Hipot tests on all 110 kV. and 50 kV. bushings, resistance tests on stator windings at Arapuni, and tests on new distance relays and on other relays. All telephone connections were checked and the system diagram brought up to date. Incorrect relay operations were investigated, and insulators were tested on the H.T. set.

44

I , 110 kV. Units. 50 kV. Units. | 50 kV. Pin. Totals. | Number tested .. .. .. .. 61,434: 13,769 ■ 15,687 90,890 Number defective by test.. .... 4 2 212 218 Number defective by inspection .. .. 2 ., 66 68 Total number defective . . . . 6 2 278 286 Percentage defective .. '.. 0-017 0-023 1-772 0-315