I).—1.

BROKEN WIRES AND POLES. There were 1,517 broken wires reported by electric-supply authorities, with 126,097 miles of conductor erected. The corresponding figures for the previous year were 1,386 broken wires and 119,432 miles of conductor in use. Trees were again the principal cause of the breaks, and accounted for 27 per cent, of the total, as against 29-4 per cent, for i 938. The following table has been prepared to show the various factors which have been reported as responsible for broken wires during the past six years : —

Causes of Breakages of Wires.

102

Note. —Percentages less than 1 per cent, of total are not shown. 1934. 1935. 1936. 1937. 1938. 1939. Total ; ; Reported Causes. for Six p er p er cen t_ Per cent- Per cent- Per cent- Per centears. Number, age of Number, age of Number, age of Number, age of Number, age of Number, age of Total. Total. Total. Total. Total. Total. Trees .. .. 2,949 262 27 319 27 1,341 47 370 28 255 29 402 27 Wires contacting .. 1,585 172 18 206 17 361 13 367 28 188 22 291 19 Galea .. .. 723 110 11 108 9 171 6 105 8 51 6 178 12 Binder-failure.. .. 794 128 13 154 13 163 6 105 8 79 9 165 11 Insulator-failure .. 223 13 1 4 13 52 4 40 5 101 7 Poles broken .. .. 266 39 4 34 3 89 3 36 3 19 2 49 3 Poles hit by vehicles .. 232 39 4 39 3 40 1 4.8 4 32 4 34 2 Corrosion .. .. 97 15 2 11 5 15 1 11 1 4:0 3 Short circuit .. . . 47 . . .. .. .. .. .. I •. 13 2 33 2 Roofins-iron .. .. 139 4 .. .. .. 90 3 12 8 . . 25 2 Birds " .. .. 92 9 1 13 1 11 18 1 20 2 21 1 Joint failure .. .. 140 12 1 30 2 22 29 2 28 3 19 1 Overstress .. .. 50 .. .. 4 .. 12 .. 16 1 4 .. 14 Snow .. .. 479 .. .. Ill 9 348 12 5 .. 2 .. 13 Span-breaks .. .. 13 .. .. .. .. .. .. .. ■ ■ ■■ •. 13 Vibration .. .. 126 1 .. 30 3 44 2 22 2 17 2 12 Blasting .. .. 31 1 ■ ■ 7 .. 6 .. 2 .. 7 .. 8 Lightning .. .. 35 2 .. 7 .. 11 .. 7 .. 2 .. 6 Contacting earth-guard.. 28 6 .. 3 .. 7 .. 2 .. 5 .. 5 Opossums . . .. 9 1 • • • • • ■ 1 • • 1 • • I • • 5 Bad workmanship .. 85 25 3 19 2 17 6 10 1 8 Jumper-failure .. 18 1 .. 4.. 2.. 6.. 1 .. 4.. Haystacker .. .. 41 9 1 10 . . 5 .. 5 .. 5 .. 7 Radio-mast .. .. 39 5 .. 12 1 12 4 2 .. 4 Football .. .. 4 .. .. .. .. 1 •• .. .. .. .. 3 Threshing-mill .. 10 2 .. 1 .. 1 .. 3 .. .. .. 3 Crane .. .. 9 .. .. 2 .. .. .. 1 .. 3 .. 3 Kite .. .. .. 8 .. .. 3 .. 1 2 .. 2 Falling pole .. .. 3 1 .. .. .. .. .. .. .. .. .. 2 Loaded lorry .. .. 5 .. .. 2 .. 1 .. .. .. .. .. 2 Wire over line.. .. 13 7 .. 3 .. 1 .. .. .. .. .. 2 Falling chimney .. 2 .. .. .. .. 1 .. •. . • • • • • 1 Ladder .. .. 1 .. .. • • • • • • • • • • • • • • • • 1 Scrub fire .. .. 27 1 .. 4 2 3 14 2 3 House fire .. ... 32 15 2 .. .. 2 .. 13 1 1 .. I Flood .. .. 7 .. .. 2 .. 3 2 Rifle-shot .. .. 7 .. .. .. .. .. .. .. .. 6 .. 1 Landslip .. .. 7 .. .. 4 .. 1 .. 1 .. .. .. 1 Aeroplane .. .. 5 2 .. .. .. 1 .. 1 .. .. .. 1 Ship's mast .. .. 6 .. .. .. .. 2 .. 1 .. 3 Cut by slasher .. 11 2 .. 2 .. 2 .. 4 .. 1 Earthquake .. .. 26 26 3 Tram-trolley pole .. 14 1 .. 3 .. .. '.. 7 .. 3 Failure under-ground cable 4 2 .. 2 Excessive sag .. .. 1 1 Straw blown on line .. 1 1 Contact with roof .. 6 2 .. 1 .. .. .. 3 Frost .. .. 17 11 1 .. .. 1 .. 1 .. 4 Broken by workmen .. 2 1 .. 1 Cross-arm burnt or broken 4 4 Contact with stay wire 8 I .. 3 .. I .. 3 Animals rubbing poles .. 3 2 .. .. .. 1 Fouled by excavator .. 1 1 Sea erosion .. .. 2 1 .. . . .. 1 Contact with pole .. 9 .. .. 3 .. 2 .. 4 Contact with P. and T. lines 12 .. .. 1 .. 10 .. 1 Contact with P.W.D. lines 6 .. .. .. .. 3 .. 3 Fouled by building material 15 4 .. 1 .. 8 .. 2 Storm damage to buildings 26 .. .. •. .. 19 .. 7 Unknown .. 179 31 3 37 3 17 33 2 29 3 32 2 Totals .. .. .. 973 .. 1,200 .. 2,853 .. 1,325 .. 866 .. 1,517 Total breakages reported for six years = 8,734, of which trees were responsible for 33-75 per cent.