HC Deb 29 February 1932 vol 262 cc777-8
56. Mr. TURTON

asked the Minister of Transport whether he will state the cost per 100 yards of placing electric cables underground and of placing the same cables overland in rural areas; and what proportion of cables have at present been laid underground?

The MINISTER of TRANSPORT (Mr. Pybus)

As the information which the hon. Member desires contains a number of figures, I will, with his permission, circulate the answer in the OFFICIAL REPORT.

Following is the answer:

It is only possible to give approximate figures as the relative costs depend upon a number of factors such as the market price of copper and lead for underground cables and of the materials used for overhead line conductors; the voltage and current-carrying capacity for which the cables and lines are intended; the nature of the rural roads in which the cables are laid and hence the cost of excavation and reinstatement; and the span and hence the number of poles per mile in the case of overhead lines.

An analysis of the returns of over 200 authorised undertakers who were supplying in rural areas at the end of March, 1930, showed that the average expendi- ture incurred up to that date on high tension systems in general was upwards of £1,000 per mile for overhead lines as compared with over £1,600 in the case of underground mains, a difference of over 60 per cent. The expenditure in the case of low tension systems in general was upwards of £560 per mile on overhead lines as compared with upwards of £1,100 on underground mains, a difference of about 100 per cent.

Since that date there has been a substantial fall in the price of materials and an alteration in the relative costs, particularly in the case of low tension systems. Estimates at the present time indicate that the approximate costs per 100 yards now range between the following figures:

Voltage. Approximate cost per 100 yards.
Overhead Lines. Underground Cables,
From
33,000 … £42 to £57 About four times the cost of overhead lines.
11,000 … £20 to £31 From £68 to £102.
400/230 … £28 to £40 From £34 to £71.

The above-mentioned analysis showed that out of upwards of 7,300 miles of high and low tension transmission and distribution lines provided by the 200 undertakers in rural areas at the end of March, 1930, about 59 per cent. were underground cables and 41 per cent. overhead lines. No later analysis is available.