OFFICE WIRES.

Office wire is usually made with a wind and a braid of cotton saturated with paraffine. It is sometimes required with a double braid or triple braid of cotton. The most common colors are red and white. Any combination of colors can be furnished.

Damp-proof Office wire has the inside wind saturated with black Weatherproof compound, while the outside finish is the same as ordinary Office wire.

Annunciator wire has a covering consisting of two wraps of cotton saturated with paraffine. The outer covering is made in solid colors or combination of two colors.

Double conductors for house wiring are of various kinds. Two conductors twisted together, without any outside cover, form a convenient method of wiring for bells, telephones, etc. These conductors may be 18 B. & S., with double braid Weatherproof or with Annunciator insulation.

Two-conductor Office wire may be two Office wires laid side by side and covered with a two-colored Office braid, or it may consist of two Annunciator wires so insulated.

Weatherproof cables consist of 18 B. & S. G. Annunciator wires, twisted into a cable and covered with rubber tape and a braid of cotton saturated with Weatherproof insulation. They weigh about ten pounds per 1 000 feet per conductor. For work inside building, in dry places, the rubber tape may be omitted, and the finishing braid made any color to correspond with the woodwork.

Lamp cord is furnished in silk or cotton insulation. Green and yellow is the standard color combination.

POWER CABLES.

WE MANUFACTURE power and electric-light

The thickness and kind of insulation depend on the use for which the cable is intended. The table of diameters and weights is based on insulation on a side, and is approximately correct for any kind of insulation.

Specifications for Underground Cable of 500 000 C. M.

1. COPPER CONDUCTOR.

The conductor shall consist of 47 wires, each 104 mils in diameter, and shall weigh not less than 1.525 pounds per foot. The copper used shall have a conductivity of not less than 98 per cent.

2. INSULATION.

The insulation shall consist of paper not less than thick, and shall form a wall of uniform thickness around the conductor.

3. SHEATH.

The insulated conductor 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 insulation resistance shall be not less than 300 megohms per mile, at 60° F.

TELEPHONE CABLES.

Lead-encased for underground or aerial use.

HE INSULATION of these cables is dry paper.

THE

We manufacture several styles of 19 B. & S. G., 20 B. & S. G., and 22 B. & S. G., according to the use for which they are intended. The most common size is 19 B. & S. G. We also supply terminals and hangers. To determine the size supporting strand to use with these cables, consult tables page 39.

Specifications for Telephone Cables.

1. CONDUCTORS.

Each conductor shall be .035 89 inches in diameter, (19 B. & S. G.,) and have a conductivity of 98 per cent. of that of pure soft copper.

2. CORE.

The conductor shall be insulated, twisted in pairs, the length of the twist not to exceed three inches, and formed into a core arranged in reverse layers.

3. SHEATH.

The core shall be enclosed in a pipe composed of lead and tin, the amount of the tin shall be not less than 2% 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. ELECTROSTATIC CAPACITY.

The average electrostatic capacity shall not exceed .080 of a microfarad per mile, each wire being measured against all the rest and a sheath grounded; the electrostatic capacity of any wires so measured shall not exceed .085 of a microfarad per mile.

5. INSULATION RESISTANCE.

Each wire shall show an insulation of not less than 500 megohms per mile, at 60° F., when laid, spliced and connected to terminal ready for use; each wire being measured against all the rest and sheath grounded.

6. CONDUCTOR RESISTANCE.

Each conductor shall have a resistance of not more than 47 B. A. ohms, at 60° F., for each mile of cable, after the cable is laid and connected to the terminals.