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continued throughout the year. The temporary 50/11 kv. substation supplying the Franklin Power Board has continued in operation throughout the year. Hamilton No. 2 (.11.0/50 kv.). —A start was made on erection of the steel structure and switchgear about the end of April, and was finished in October, except for the extra steelwork and additional oil-switches which were ordered subsequently to the main structure. Hamilton No. 1 (50/11 kv.). —Three additional 500 kv.a. transformers were dried out and installed, thus duplicating the previous installation of 1,500 kv.a. capacity. The necessary pole structure and air-break switches were erected to control these, and the new bank was almost ready to go in service at the end of the year. Extensions to Hamilton workshop were started, and the old crane from Horahora was transferred for use in the workshop. Plans were prepared for a new test-room, and new layout for the substation. Waikino (50/11 kv.). —A 1,500 kv.a. synchronous condenser was, placed in service in November, this serving both to improve power-factor at Horahora, and to enable voltage at Waikino to be controlled. The additional 50 kv. lines terminating at Waikino— i.e., those from McLaren's Falls and Bombay —in addition to the original Horahora-Waikino line, made the installation of 50 kv. oilswitches on each line desirable, together with a bus-sectionalizing oil-switch. These four oil-switches, and lightning arresters on the Bombay and McLaren's lines, were installed during the year, the work being completed in November. The original horn gap and resistance arresters on the Waihi 11 kv. line were replaced by Oxide film pellet-type arresters. Takapuna (50/11 kv.). —Construction work on the steelwork and. switch-gear was completed in May, and this was put in service, replacing the temporary installation, which had been in service since the previous December. Henderson ( Waitemala) (50/11 kv.). —The work was completed on the steel structure and the permanent equipment put in operation in November, replacing the temporary installation which had been in service since the previous December. Kerepeehi (50/11 kv.). —A 1,000 kv.a. three-phase transformer, with air-break switches controlling the 50 kv. side, was put in service on the 10th July. Construction of the substation building started in August, and was completed in March. A house also was completed, but the permanent substation switch-gear and transformers did not arrive during the year. Mamaku (50/11 kv. to 150 kv.a.). —This substation was completed and placed in service on the 14th April. Edgecumbe (Rangitaiki), Waiotahi, Huntly, and Matamata Substations (50 kv.). —Sites were selected for these substations, the first two to supply the Bay of Plenty Power Board, and the others for Central Power Board and Thames Valley Board, and the necessary equipment was ordered to enable them to be completed towards the end of 1928. New transformers were ordered for Waikino Substation (7-1,000 kv.a.) and for Waihou (4-750 kv.a.) to be connected 50 kv. delta to 11 kv. star, to be substituted for the original star-star and deltadelta connected transformers at these two points, so that that operation with the 11 kv. neutral earthed would be possible. The transformers thus replaced at Waikino arc to be sent to the Gisborne substation, and those replaced at Waihou to the two Bay of Plenty substations. Operation and Maintenance. Headworks and Power-house, Horahora. The plant has been running on. overload almost every day now for two years, and has on occasions been carrying continuous overload for ten days at a time. This apparently, has not had any detrimental effect on the machines, but it has necessitated refitting of a number of the switch contacts and connections to prevent overheating. Apart from trouble directly due to the debris brought down by the Arapuni diversion, the following difficulties have been met with : — (1) Failure in May of 1,310 kv.a. main transformer, 5/50 kv., No. 2 transformer, No. 2 bank. The failure was due to breakdown of one of the 50,000-volt. porcelain bushings, which, flashed over inside the tank and punctured the top turn of the lead cooling-coils. The punctured turn was removed, the damaged bushing replaced by a spare, and the transformer dried out and put in the spare position. (2) One of the guide-wheel castings of No. 1 turbine was found seriously worn, and a new one was ordered from the makers to replace it. Replacement was carried out in February, and took about three weeks. (3) The three cables carrying power from the power-station to the transformer-house were found to be heating excessively. (The fourth had previously been replaced by overhead wires.) This was remedied by placing split 12 in. earthenware pipes around them to allow ventilation. (4) To improve ventilation, the holes that had previously been cut through the bottom of the generator-pits were enlarged. (5) Six cracked vanes in No. 2 runner of No. 5 turbine were repaired by welding ; also on. No. 2 turbine, three vanes on No. 4 runner and four on No. 3 runner ; on No. 3 turbine, two on No. 3 runner and one on No. 2 runner; and on No. 4 turbine, two on No. 3 runner and two on No. 2 runner. A lamp was connected in the secondary of No. 2 neutral earthing transformer to indicate discharge to earth. Overload and earth-leakage relays were put in service on outgoing 11 kv. feeders in October. On the installation of the synchronous condenser at Waikino, voltage at Horahora was lowered 5 per cent, and was raised at all substations a corresponding amount on the 11th December.