The estimates given in Table No. 2 were criticised by Mr. Kapp, who thought that “a more reliable conductor could be obtained by using a high-class lead-covered cable, which might be laid in the ground with the simple protection of a rough tarred plank to cover it.” The cost of digging the trench and running in the cable from the drum was quoted at 3_s._ a yard, and the total cost, inclusive of £10 for surface boxes, at £155 per 100 yards, instead of £187, as shown by the Table.
_Cost of Laying 100 Yards of Double Conductor underneath the Footway of a London Street._
-------------------------------+---------+--------+--------+ | Single. | 7/16 | 19/15 | | No. 16. | | | -------------------------------+---------+--------+--------+ Area, square inch | ·0032 | ·0225 | ·0773 | Area, square millimetre | 2·08 | 14·6 | 50 | Weight per 100 yards run lb. | 7½ | 53½ | 183¼ | Cost of copper at 7¾_d._ |£ 0 4 10| 1 14 6| 5 18 0| Cost of insulation | 1 3 2| 4 8 6|11 2 0| +---------+--------+--------+ Total cost of Cables | 1 8 0| 6 3 0|17 0 0| Casing, bitumen, and cement | 5 3 0| 5 5 0| 8 0 0| Labour, Laying | 3 0 0| 4 0 0| 5 0 0| Trenching and repairing | 25 0 0|25 0 0|25 0 0| Surface boxes and connection | 5 0 0| 7 0 0|10 0 0| Engineer and superintendent | 3 0 0| 4 0 0| 5 0 0| +---------+--------+--------+ Total |£42 11 0|51 8 0|70 0 0| Add extra if copper, at | | | | 9½_d._ | 0 1 1| 0 8 0| 1 7 0| +---------+--------+--------+ | 42 12 1|51 16 0|71 7 0| Cost of copper per lb., | | | | laid complete | 5 13 6| 0 19 4| 0 7 9| Current in ampères | 1·2 | 8·1 | 28 | Cost per ampère | 35 10 0| 6 8 0| 2 10 6| -------------------------------+---------+--------+--------+
-------------------------------+--------+---------+ | 19/12 | 19/10 | | | | -------------------------------+--------+---------+ Area, square inches | ·1613 | 0·25 | Area, square millimetres | 104 | 161·25 | Weight per 100 yards run lb. | 392 | 576 | Cost of copper at 7¾_d._ |12 13 0| 18 15 0| Cost of insulation |24 17 0| 35 17 0| +--------+---------+ Total cost of Cables |37 10 0| 54 12 0| Casing, bitumen, and cement |12 10 0| 12 10 0| Labour, Laying | 5 0 0| 6 0 0| Trenching and repairing |25 0 0| 25 0 0| Surface boxes and connection |10 0 0| 10 0 0| Engineer and superintendent | 5 0 0| 6 0 0| +--------+---------+ Total |95 0 0|114 2 0| Add extra if copper, at | | | 9½_d._ | 2 17 0| 3 5 0| +--------+---------+ |97 17 0|117 7 0| Cost of copper per lb., | | | laid complete | 0 5 0| 0 4 1| Current in ampères | 58 | 90 | Cost per ampère | 1 13 9 | 1 6 0| -------------------------------+--------+---------+