New Zealand Gazette – 1927 – No. 48

Page 2376

✨ Electrical Supply Regulations



2376 THE NEW ZEALAND GAZETTE. [No. 48

SCHEDULE.

STILL-AIR SAG AND TENSION TABLES FOR ELECTRICAL CONDUCTORS.

MAXIMUM TENSION AND MINIMUM SAG ALLOWABLE.

TABLE I.—BARE (H.D.) COPPER.

Wind, 12 lb. per square foot of diametral plane.

Constants.—Coefficient of thermal expansion = 9.45 x 10⁻⁶ per degree Fahrenheit ; maximum allowable stress = 25,000 lb. per square inch ; modulus of elasticity = 18 x 10⁶ lb. per square inch.

(A.) 7/036 in. (7/20 S.W.G.).

Constants.—Area, 0.00712 sq. in. ; diameter, 0.108 in. ; loading factor, 3.987 ; maximum tension in conductor, 178 lb. ; weight, 0.028 lb. per foot.

Span. Datum. 0. Degrees Fahrenheit above Datum. 20. 40. 60. 80. 100.
Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag.
Ft. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in.
120 150 0 4 126 0 5 104 0 6 1/2 83 0 7 66 0 9 50 1 0
140 141 0 6 118 0 7 97 0 8 1/2 78 0 10 1/2 62 1 1 49 1 5
160 131 0 8 109 0 10 89 1 0 72 1 3 59 1 6 48 1 10
180 119 0 11 1/2 99 1 2 82 1 5 67 1 8 56 2 0 47 2 5

(B.) 7/044 in.

Constants.—Area, 0.01064 sq. in. ; diameter, 0.132 in. ; loading factor, 3.308 ; maximum tension in conductor, 266 lb. ; weight, 0.0418 lb. per foot.

Span. Datum. 0. Degrees Fahrenheit above Datum. 20. 40. 60. 80. 100.
Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag.
Ft. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in.
120 239 0 3 1/2 203 0 4 1/2 169 0 5 1/2 137 0 6 1/2 108 0 8 1/2 83 0 11
140 229 0 5 1/2 195 0 6 1/2 162 0 7 1/2 131 0 9 1/2 104 1 0 83 1 3
160 218 0 7 1/2 185 0 8 1/2 154 0 10 1/2 125 1 1 101 1 4 83 1 8
180 207 0 10 175 0 11 1/2 145 1 2 120 1 5 99 1 8 82 2 1

(C.) 7/052 in.

Constants.—Area, 0.01483 sq. in. ; diameter, 0.156 in. ; loading factor, 2.852 ; maximum tension in conductor, 371 lb. ; weight, 0.0583 lb. per foot.

Span. Datum. 0. Degrees Fahrenheit above Datum. 20. 40. 60. 80. 100.
Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag.
Ft. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in.
120 344 0 3 1/2 287 0 4 1/2 243 0 5 1/2 200 0 6 1/2 159 0 8 122 0 10
140 334 0 5 1/2 282 0 6 1/2 229 0 7 1/2 187 0 9 158 0 11 123 1 2
160 323 0 7 268 0 8 1/2 225 0 10 185 1 0 157 1 2 124 1 6
180 311 0 9 263 0 11 221 1 1 181 1 3 155 1 6 125 1 11

(D.) 7/064 in. (7/16 S.W.G.).

Constants.—Area, 0.0225 sq. in. ; diameter, 0.192 in. ; loading factor, 2.39 ; maximum tension in conductor, 562 lb. ; weight, 0.0885 lb. per foot.

Span. Datum. 0. Degrees Fahrenheit above Datum. 20. 40. 60. 80. 100.
Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag. Ten. Sag.
Ft. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in. lb. Ft. in.
120 534 0 3 1/2 460 0 4 1/2 387 0 5 317 0 6 252 0 7 1/2 195 0 10
140 524 0 5 451 0 5 1/2 380 0 7 312 0 8 1/2 250 0 10 1/2 199 1 1
160 515 0 6 1/2 441 0 7 1/2 372 0 9 307 0 11 249 1 2 202 1 5
180 502 0 8 1/2 431 0 10 364 1 0 302 1 2 248 1 5 204 1 9


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