| No. of Conductors | Gauge of Conductors (B. & S.) | No. of Armour Wires | Gauge of Armour Wires B. W. G. | Outside Diameter (inch) | Weight per 1,000 Feet | |
|---|---|---|---|---|---|---|
| 1 | 14 | 12 | 8 | ⅞ | 1,150 | |
| 2 | 14 | 16 | 8 | 1 | 31/32 | 1,675 |
| 3 | 14 | 14 | 6 | 1¼ | 2,400 | |
| 4 | 14 | 16 | 6 | 1 | 5/16 | 2,750 |
| 5 | 14 | 19 | 6 | 1 | ⅜ | 3,100 |
| 6 | 14 | 21 | 6 | 1 | ½ | 3,500 |
| 7 | 14 | 21 | 6 | 1 | ½ | 3,600 |
| 10 | 14 | 22 | 4 | 1 | ⅞ | 4,600 |
NOTE.—The above specifications refer only to river and harbor cables. Ocean cables are of an entirely different character, and consist of "shore end," "intermediate" and "deep sea" types.
Fig. 813.—Gas engine ignition cable. This is a special cable made to stand the hard service necessary on automobiles. The conductor is composed of 36 strands of No. 27 tinned copper wire, equal to No. 14 in capacity, which gives it necessary flexibility. About this conductor are woven two layers of cotton thread. Over this are woven, in opposite directions, several layers of specially prepared tape which has been given two coatings of fine insulating varnish. Two strong braids of cotton form the outside covering, and each of these different braids is passed through a bath of insulating liquid and baked in a steam heated oven. With three layers of tape the cable will stand a test of 18,000 to 20,000 volts, and with five layers, 30,000 volts.
Fig. 814.—Paper insulated lead encased telephone cable.
Ques. For what service is slow burning weather proof wire not suited?
Ans. It is not adapted to outside work.