voltages require an increased separation of personnel and energized circuits.
Many other safety procedures are required on the job& - too many to list here. The Lineman's and Cableman's Handbook, the Electrical Transmission and Distibution Safety Manual, NAVFAC P-1060, and Occupational Safety and Health Administration instructions are a few references you need to read to learn more about job safety.
Power line components are the different items used to construct a power distribution line. The basic components of a power line are poles, guys, crossarms, insulators, and conductors.
The three types of poles used most frequently in pole-line construction are wood, concrete, and steel. You will find all three types of poles in the field, but most of your work will be with the wooden type.
All wooden poles used for line work are chemically treated to resist damage caused by insects and rotting. Many of the older poles now in use were treated with creosote. Most new poles are treated with less toxic chemicals and are therefore safer to work with.
WARNING Creosote is a toxic compound that irritates the skin and sometimes causes blistering. You should use extra care when working around poles treated with creosote to prevent contact between these poles and the bare skin.
The supply of wood poles available for use in constructing electric power lines has decreased in recent years. Substitute materials, such as concrete, aluminum, fiber glass and laminated and composite wood poles, are now being used.
The classification of wooden poles is determined by the length, circumference at the top, and circumference measured 6 feet from the butt end. Pole sizes begin at 20 feet and are increased in 5-foot increments up to 90 feet in length. Pole-top circumference increases 2 inches for every class from Class 7 to Class 1. The Navy, however, does not normally order poles smaller than Class 5. American National Standard, ANSI 05.1, entitled "Specifications and Dimensions for Wood Poles" provides technical data for wood utility poles.
When constructing power lines, you will need a means of strengthening poles and keeping them in position. To accomplish this, you can use guys, anchors, and braces. Anchors are buried in the ground, and guy wires are connected to the anchors and attached to the pole, or a push brace may be used. The guys and braces are used to counter the horizontal strain on the pole caused by conductors, pole-line components, and abnormal loads, such as snow, sleet, or wind.
Anchors are designed to meet specific soil conditions. You must know the type of soil before you can select a certain type of anchor. Anchors come in many forms and have different methods of installation. Figure 4-1 shows the most common types of anchors. The expanding anchor, the most popular type, as shown in figure 4-1, view A, is designed to be placed in the ground and then expanded with the aid of the tamping bar. Once expanded, the anchor is secure and strong enough to secure the guy. Figure 4-1, view B, shows a plate of a never-creep anchor, and view C shows a screw anchor that is installed using an earth auger. These three types of anchors are manufactured and are commonly used because of their ease of installation.
Another type of anchor that is shown in figure 4-1, view D, is called a deadman. This anchor is made of a 6- to 8-foot-long piece of treated power pole and an anchor rod. It is installed 6 feet deep in loose or sandy type of soil, with an angle of pull for the guy wire and rod assembly equal to 45 degrees. The deadman is not widely used today because of the time and effort required to place it.
The anchor rod serves as the connecting link between the anchor and the guy cable. The rod mustContinue Reading