Mounting the Reels No matter how you string the wire, you will have to mount the reels on some support that allows them to revolve freely. This is usually done by raising a reel on reel jacks, as shown in figure 4-64. A metal rod strong enough to support the reel is put through the hole in the center, and the rod and reel are jacked up on each side with the leg of the T-base away from the reel, as shown. You may have to fasten down the bases of the jacks to keep the strain from upsetting the reel. When you are jacking up, it is necessary only to raise the reel just clear of the deck. When you are stringing wire in rough terrain, the best method is to anchor a reel to the ground at the end of the line by means of guys run to driven stakes. Then run a rope line over the crossarms or through running blocks mounted on the crossarms for a distance of 1,000 to 1,500 feet. This is accomplished by a lineman climbing each pole and placing the rope in place.

After the rope has been strung over the crossarms, one end is secured to the wires to be pulled, and a couple of turns are taken with the other end around the winch drum on the line truck. The drum is then rotated to haul in the rope and the wires with it. As each wire passes a crossarm, a lineman must climb the pole to set the wire in proper position and guard against twisting.

To keep a paying-out reel from revolving too fast, set a brake or drag against the reel. This can be simply a board, held against the outer edge of the reel by a helper. As a wire or wires are being pulled, enough crew

Figure 4-64.- Cable reel on reel jacks.

members must be stationed along the way to establish a chain of signal communication from the head of the line back to the line truck.

Placing the Neutral Conductor A neutral conductor should always be placed on a center crossarm pin or on a pole-top pin. Butting the neutral on a center pole pin gives the lineman a clear space around the pole to climb through; that is, it ensures that the hot wires are a considerable distance apart.

Pulling In When the conductors have been hoisted in place on the crossarms and dead-ended on one end, you are ready to start "pulling in"; that is, heaving on the conductors until each has been raised to proper sag. You can do this with a tackle equipped with cable grips like those shown in figure 4-65 or individually, using a cable grip and a come-along.

A cable grip is a clamp device that grips the wire tightly when a strain is applied to the grip.

When you are pulling two or more wires at once, it is best to use the equalizer, as shown in figure 4-65. This device distributes the strain equally on all the wires.

Measuring the Sag When wires have been pulled to approximately the desired sag, a lineman goes to the center span to measure the sag. Measurement at the center of each span ensures uniformity. Three common ways of measuring sag are by dynamometer, by timing vibration, and by the use of targets. 

DYNAMOMETER.- Alever-cam dynamometer is an instrument that is installed in the pulling line and that measures the strain of the pull. It is used in conjunction with a chart that gives the desired pull tension for a given conductor size, span length, and temperature. A traction dynamometer, also installed in the pulling line, provides direct readings on the face of the dial.

TIMING VIBRATION.- The timing-vibration process is done by striking the wire sharply near one of the pole supports and by timing with a stopwatch, the interval that elapses as the impulse from the blow travels to the next pole and returns. This system is not accurate when wind is swinging the line or when the line is being worked on in an adjacent span.

Figure 4-65.- Pulling wires with an equalizer.

Table 4-2.- Sag Variation with Temperature

Figure 4-66.- Effect of temperature on sag in 200-foot span of 00 wire.

Figure 4-67.- Adjusting sag. Figure 4-66 shows the effect of temperature on the sag in a 200-foot span of 00 wire. You target-measure sag by nailing slat targets, such as a couple of pieces of wood lath, at the point on each pole below the conductor insulator that creates the desired amount of sag. A lineman then sights from one slat to the other, and the conductor is hauled up or lowered until its lowest point

is on the line of sight between the slats (fig. 4-67). After the wires are "sagged in," you allow a rest period of from 1/ 2 hour to 4 hours (varying according to the length of the pull) to let the wires adjust themselves to the tension in the pull. They will gradually "creep" until tension in all the spans is equalized. After they have crept to the final position, you are ready to "tie in."