368
PUBLIC
RECORD OFFICE
Reference :-
7
11111 ¶C.O.885
ALTHOUT PERMISSION OF THE RECORD OFFICE, LONDON BE REPRODUCED PHOTOGRAPHIC- COPYRIGHT PHOTOGRAPH-NOT TO.
PU
Irregulari-
ties and welds.
Galvaniz- ing.
Com- pounding of wires.
50
The galvanized steel wires to be No. 13 S.W.G., equal to 095 of an inch when galvanized, or within 24 per cent. thereof, and to bear a breaking strain of not less than 85 tons per square inch, with an elongation of not less than four per cent.
The wire to be capable of being bent round its own diameter three times and unbent three times without breaking.
The wire to be in bundles of not less than 2 cwts., and to have no more than one weld in each bundle.
(K.) The wire to be free from splinters and irregularities, no brittle wire to be put in the cable, nor weld made within 12 feet of any other weld. All joints in the sheathing wires to be welded, either electrically or by efficient workmen, no brazes or soldered joints to be made.
(L.) The galvanized wire to withstand four immersions of one minute cach in a solution of sulphate of copper (one sulphate to five water by weight), without showing a trace of copper coating.
(M.) Before being used for the sheathing of the cables the galvanized wire for all the types is to be heated in a kiln or oven just sufficiently to drive off all moisture, and, whilst warm, is to be dipped into a hot compound not containing anything deleterious to the core, and so prepared as to adhere to the wire, and form, when set, a perfectly fixed preservative coating that will not come off in passing through the closing machine."
OUTER SERVING.
(N.) Types AA, E, B, and B', manufactured as above, to be covered with two servings of jute yarn steeped in "freed" coal tar and laid on spirally in opposite directions, alternating with three coatings of Clark's compound applied hot.
(O.) Type D, manufactured as above, to be covered with two Hessian canvas tapes, soaked in an approved preservative compound, and laid on spirally in opposite directions, alternating with three coatings of Clark's compound. -
GENERAL CONDITIONS.
The manufacture of the cable shall not be carried on at night without the consent of the engineer.
No coils of core shall be sheathed before they have been tested and approved by the engineer or his representative appointed for that duty.
All coils shall be labelled, numbered and registered, and as the manufacture of the cable proceeds, the engineer or his representative shall be supplied with a complete list showing the order in which they are placed in the cabile.
The joints in the core are to be inade by experienced workmen. In every case one joint maker is to be employed to join the conducting wire, and another to supply the insulating covering. Each joint shall, if required, he inspected, tested and passed by the engineer or his assistant before it is allowed to pass into the cable.
Reasonable notice shall be given to the engineer or his assistant when each joint is to be made, to enable him to be present at its making, if he so desires, and ample time shall be allowed for a satisfactory test, six hours after it has been immersed in water.
The manufacture of the cable in every stage, as well as the materials and compounds
used therein, shall be of the best, and be satisfactory to the engineer.
The sections of the cable under manufacture shall be handed over for daily testing to the engineer, with a memorandum for cach, showing the numbers, weights and lengths of the coils jointed on during the previous 24hours, the total length in circuit and the length completed, and sufficient time shall be given for proper and satisfactory tests to
be taken.
Every nautical mile of cable shall be carefully marked with a lead tally on which the number is stamped and securely fixed at the end of each mile.
The cable, when manufactured, shall be coiled in suitable water-tight tanks, receiving at the same time a good coating of whitewash, and shall be kept as far as practicable constantly under water.
A separate and convenient room for testing the core and cable, with instruments and batteries, is to be provided by the contractors at their works for the engineer's electrician, and free access to the works is to be given to the engineer or his representative, and also every facility for testing and examining the cable and materials.
51
The cable shall be shipped from the contractors' works direct into the tanks of the ship. It shall receive at the same time a thorough coating of chalk and water.
The vessel on which the cable is shipped for transport shall not leave her moorings until the cable has been tested from the shore by the engineer or his representative to his satisfaction, and ample time shall be allowed after the completion of the shipment for this purpose.
During the transport the cable shall, as far as practicable, be kept under water, and tested each day by the contractors' electricians, and a complete copy of the tests shall be supplied to the engineer.
No damaged cable shall be laid, and the engineer shall be entitled to refuse to allow any portion of the cable to be laid which, in his opinion, is damaged and unfit for use.
The electrical condition of every portion of the cable when manufactured and of the entire cable when shipped, and also of the completed cable when laid, shall be such as, having regard to its previous condition, and making due allowance for the mean actual temperature of the water, as shown by the resistance of the conductor, to give no good. grounds for believing that any fault exists in the insulator or conductor.'"
H. A. TAYLOR,
April 6th, 1900.
Engineer.
G8
5806-5
in