THE

TELEGRAPH CABLES.

Lead-encased for underground use.

HESE cables are made of either rubber, cotton or paper insulation. The sizes and weights are approximately correct for rubber and cotton insulation. Both sizes and weights are slightly reduced for paper insulation. In all cases the cables are lead-encased.

Specifications for Telegraph Cables.

1. CONDUCTORS.

Each conductor shall be .064 inches in diameter, (14 B. & S. G.,) and have a conductivity of 98 per cent. of that of pure copper.

2. CORE.

The conductors shall be insulated to with cotton, and formed into a core arranged in reverse layers. This core shall be dried and saturated with approved insulating compound.

3. SHEATH.

The core shall be enclosed in a pipe composed of lead and tin. The amount of tin shall not be less than 2.9 per cent. The pipe shall be formed around the core, and shall be free from holes or other defects, and of uniform thickness and composition.

4. INSULATION RESISTANCE.

The wire shall show an insulation of not less than 300 megohms per mile, at 60° F., when laid, spliced and connected to terminals ready for use, each wire being measured against all the rest and the sheath grounded.

5. CONDUCTOR RESISTANCE.

Each conductor shall have a resistance of not more than 28 International ohms, at 60° F., for each mile of cable, after the cable is laid and connected up to the terminals.

TH

AERIAL CABLES.

HESE cables are made from double-coated rubber wire, taped. After standing, the cable is doubletaped and covered with tarred jute, over which is placed a braid of heavy cotton saturated with Weatherproof compound. This outside covering protects the rubber from the action of the air and from mechanical injury. The separate wires are tested in water, and no wire is used which will not fully meet a water test. The result is a cable which will work under water as well as on a pole line, if there is no danger of mechanical injury. The ordinary size for telegraphic work is 14 B. & S., insulated to 32. A trace wire can be placed in each layer, if desired.

The size galvanized strand to support these cables may be found from the table page 39. Suppose the span is 130 feet and a 10-conductor 14 B. & S. G. Aerial cable is used, then from these tables it is seen a 4-inch ordinary galvanized strand will support a cable weighing 423 pounds per 1000 feet, with a 130-foot span.

Specifications for 14 B. & S. Aerial Cable.
1. CONDUCTORS.

Each conductor shall be .064 inches in diameter, (14 B. & S. G.,) and have a conductivity of 98 per cent. of that of pure copper.

2. CORE.

The conductors shall be insulated to with rubber and tape, and formed into a core arranged in reverse layers.

3. PROTECTIVE COVERING.

The core shall be covered with two wraps of friction tape and one wrap of tarred jute. Over this there shall be a braid saturated with Weatherproof compound.

4. INSULATION RESISTANCE.

Each wire shall show an insulation resistance of not less than 300 megohms per mile, at 60° F., after being immersed in water 24 hours. This test shall be made on the core after all the conductors are laid up, but before the outside coverings are put on.

5. CONDUCTOR RESISTANCE.

Each conductor shall have a resistance of not more than 28 International ohms, at 60° F., for each mile of cable.

The core consists of 7 × 22 B. & S. tinned copper wires, insulated with rubber to of an inch, laid up with proper jute bedding.

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We are prepared to furnish telegraph cables with gutta-percha insulation. This is the best insulation for submarine work, and its reliability and durability more than make up the difference in cost between it and any other insulation.

We are prepared to furnish submarine cables of any description for use in electric lighting and street railway work.

No list of these cables can be made, owing to the varying conditions to be met.