CO885-(7-8) — Page 107

PUBLIC

RECORD OFFICE

Reference :--

ECO.885¬

7

PUBLIC RECORD OFFICE, LONDON ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC-

COPYRIGHT PHOTOGRAPH-NOT TO

Pressure Tent.

Joints in Core.

Storage of Core.

Serving.

14

For the purposes of these tests the core shall be immersed, for at least 24 hours, in water having as nearly as practicable a temperature of 75° and 60° Fahrenheit respectively. A margin of 5 per cent. over and under the specified weights of conductor and dielectric being allowed, a corresponding margin in the resistances per nautical mile of the conductor and dielectric and in the capacity per nautical mile above specified, as far as these values are affected by such variation in weight, shall be allowed,

This allowance, boyever, to be applicable to single lengths of core completed cable.

only, and not to

The core shall be subjected under water to a pressure test of at least four English tons, or 80 ewts, to the square inch, in a suitable pressure tank, atud shall be tested with an alternating electric current of not less than :—

7,500 volts, mean voltage, for the fi. core.

5,000 4,000

+

"

"

B. core.

A. core.

་

No core shall be employed for the manufacture of the cable which does not comply with the aforesaid conditions.

The joints between single lengths of core are to be made by experienced workmen. In every case one joint maker is to be employed to join the conducting wires, and another to apply the insulating covering,

Each joint in the completed core shall be submitted for testing to the Government Engineers. Sufficient time shall be allowed by the Contractors for this operation.

Every joint in the core shall be tested by accumulation, and the leakage from any joint during one minute shall not be more than the leakage from the perfect core of a length twice that of the joint.

The core shall be coiled on drums, and shall be kept under water until it is taken to the sheathing works for the purpose of receiving its outer covering. The core on the drums is to be carefully protected.

The serving of tanned jute yarn laid round the core shall be kept wet during the process of sheathing the core.

The wire to be free from flaws, splits, splinters, irregularities, or other defects, and to Steel wires. be woll and evenly galvanised, free from lumps of zinc on the surface. Margin

allowed in diameter

of steel

wires.

Breaking

strain and elongation

A margin of 23 per cent, over and under the diameter specified for steel wires having a diameter of less than 0-200 of an inch, and of 5 per cent. over and under the diameter specifier for steel wires having a diameter of or exceeding 0200 of an inch, shall be allowed, but the mean diameter of each separate supply of each size of wire from the manta- facturer of the wire must not be less than the specified diameter.

The galvanised steel wire for the deep sen cable No. 1 shall have a breaking strain of not less than 96 tous per square inch, with an elongation averaging from 4 to 6 per cent. of the tem- when tested in lengths of 10 inches. The elongatioir of the wire in any coil, however, not pered steel to be less than 3 or more than 9 per cent, when tested in lengths of 10 inches. wire.

Ductility af steel wire.

Galvani-

wing.

The wire shall be tested for elongation by fastening the length to be tested betweer clamps 10 inches apart. The length of the wire at these two places 10 inches apart to be marked before subjecting it to the test. When the wire lus been elongated and broken under the test, the length of the stretched wire between the two marks, originally 10 inches apart, to be measured to ascertain the percentage of elongation. Or the wire may be tested by means of an apparatus (called an elongation rod) consisting of two rods of steel, one being fixed to a metal tube with a scule attached to it, the other sliding freely inside the tube, and carrying an index, so that by the sliding motion of this rod divisions on the fixed scale may be read off. Each rod at its other end, is bent in such a manner as to form a clip firmly to grip the wire to be tested for elongation. The two places where the wire is held by the clips during the test are 10 inches apart when the index carried by the sliding rod is on zero, and on exposing the wire to strain the index of the movable rod indicates on the scale the length by which the wire is being elongated.

The galvanised steel wires shall be capable of being wound round a wire or rod of their own diameter respectively, and wound back again without breaking.

The galvanised wire when dipped into a saturated solution of sulphate of copper having a temperature of 60° Fahrenheit, and allowed to remain in the solution for one minute, then withdrawn and wiped clean, shall admit of this process being performed four times without there being any sign of a reddish deposit of copper on the wire. The galvanised wire shall also, on being bent round a rod seven times the diameter of the wire, show no injury to the galvanising.

15

25%

Of each separate supply of each size of steel wire from the manufacturers of the wire, Testing of the contractors shall test, at both ends, 10 per cent, of the coils of wire of such supply in steel wire. the case of galvanised tempered steel wires, and 5 per cent. of the coils of wire of snel supply in the case of galvanised soft steel wire, and if, on examination, such wire does not meet the requirements specified in this schedule, the whole of the separate supply from which such wire is taken shall be rejected, and no portion of it shall, on any account, be again presented for exaraination and testing. No coil of wire which, on being tested, does not fulfil the requirements specified shall be used in the manufacture of the cable.

No wire of brittle quality shall be employed, and hanks which break frequently in the closing machine are not to be used in the manufacture of the cable. In order to avoid the employment of brittle wire, both ends of each coil of wire having a diameter of less than 0-200 of an inch shall be tested by forming a kink in the wire, under which test the wire must not break. Should the wire break under this test, such coil is to be rejected and not to be used in the manufacture of the cable.

No weld or braze in the sheathing wire of the cable shall, as far as may be practi-Welds in cable, be placed, or made, within 10 feet of any other weld or braze, and all welds or brazes are to be galvanised or tinned.

steel wire.

The cable when completed is to be coiled in suitable water-tight tanks, so situated Storage of that the cable can be afterwards, at all tides, coiled on board the ships for While in the tanks the cable shall, as much as

transport. possible, be kept under water.

Cable,

The water

is to be withdrawn by the Contractors from the tanks and replaced by them as often as may be necessary.

The tanks and other parts of the works where the cable is manufactured are to be roofed over, and the coils of cable and core protected from the sun.

Correct indicators are to be attached to each closing machine, showing the exact Indicators. length of cable manufactured.

marks.

Every joint in the core is to be marked outside the finished cable with a distinguish- Joint ing mark.

Each length of cable, as made from day to day, and before final shipment, shall be Tests of submitted for testing to the Government Engineer, and the electrical condition of each Cable. length of cable completed shall be in every respect in conformity with, or at least equal to, the electrical condition of the sum of the single lengths of core constituting cach respective length of cable, due regard being paid to variation of temperature at which the tests of the completed cable and the said lengths of core aré taken.

room at works.

A separate and convenient room for testing the core and cable, and suitable space for Separate batteries, are to be provided by the Contractors at their works for the Government testing Engineer and staff (referred to in the Agreement), and all connections with such testing room are to be provided by the Contractors, The Contractors shall also provide a battery-man to be in attendance on the said representatives or electricians employed in testing the core and cable.

The Government Engineers shall have the right to inspect and examine and to test - Power to the core, cable, and the materials used or intended to be used in their manufacture, or any reject. -part thereof, and also the right to be present and to witness any of the tests to be made by the Contractors of the said core, cable, or materials, and they shall have power to reject any core, wire, or other material, or completed cable, which are not in accordance with the Specification,

B.

SPECIFICATION FOR THE SHIPPING, TRANSPORT, AND LAYING OF THE CABLE.

The cable shall be shipped from the Contractors' works, and shall be laid Destina- between a point on the coast of

and a point on the coast of tion. and shall be connected with the cable-louses at these points

so as to give direct electrical communication between them.

The exact points of landing to be determined by the Contractors. The cable shall be put on board from the Contractors' works by means of suitable Shipping. machinery and in a proper and efficient manner. The cable shall be stowed in suitable tanks provided on board the vessel or vessels intended for its transport and laying. It