Pin type or post type of distribution primary insulators can be covered by hoods. The insulator hood properly installed will overlap the line hose, providing the lineman with complete shielding from the energized conductors.
Insulator hoods, like all other rubber insulating protective equipment, must be treated with care, kept clean, and inspected at regular intervals. Canvas bags of the proper size attached to a handline should be used to raise and lower the protective equipment when it is to be installed and removed.
A conductor cover, fabricated from high-dielectric polyethylene, clips on and covers conductors up to 2 inches in diameter. A positive air gap is maintained by a swinging latch that can be loosened only by a one- quarter turn with a clamp stick.
Insulator covers are fabricated from high- dielectric polyethylene and are designed to be used in conjunction with two conductor covers. The insulator cover fits over the insulator and locks with a conductor cover on each end. A polypropylene rope swings under the crossarm and hooks with a clamp stick, thus preventing the insulator cover from being moved upward by bumping or wind gusts.
High-dielectric-strength polyethylene crossarm covers are used to prevent tie wires from contacting the crossarm when conductors adjacent to insulators are being tied or untied. It is designed for single- or double-arm construction with slots provided for the double-arm bolts. Flanges above the slots shield the ends of the double-arm bolts.
Polyethylene-constructed pole covers are designed to insulate the pole in the area adjacent to high-voltage conductors. The pole covers are available in various lengths. Positive-hold polypropylene rope handles are knotted through holes in the overlap area of the cover.
Rubber Insulating Blankets Odd-shaped conductors and equipment usually can be covered best with a rubber insulating blanket. The blankets, like other protective equipment, must receive careful treatment. The rubber insulating blankets are stored in canvas rolls or metal canisters to protect them when they are not in use. The blankets can be held in place by ropes or large wooden clamps.
In-service care of insulating blankets is specified in ANSI/ASTM D1048 standard.
Hard hats, or safety hats, are worn by linemen, cablemen, and groundmen to protect the worker against an impact from falling or moving objects and against accidental electrical contact of the head and energized equipment. In addition, hard hats protect the worker from sunrays, cold, rain, sleet, and snow. The first combined impact-resisting and electrical- insulating hat was introduced in 1952. The hat was designed "to roll with the punch" by distributing the force of a blow over the entire head. This feature is accomplished' by a suspension band which holds the hat about an inch away from the head and lets the hat work as a shock absorber.
The hard hat is made of fiber glass, or plastic material, and has an insulating value of approximately 20,000 volts. New helmets are manufactured to withstand a test of 30,000 volts without failure. The actual voltage that the hat will sustain while being worn depends upon the cleanliness of the hat, weather conditions, the type of electrode contacted, and other variables. The wearing of safety hats by linemen and cablemen has greatly reduced electrical contacts.
Physical injuries to the head have been practically eliminated as a result of workers on the ground wearing protective helmets. The Occupational Safety and Health Act of 1970 and most companies' safety rules require linemen, cablemen, and groundmen to wear safety hats while performing physical work. Specifications for safety hats are found in ANSI Standard Z89.1, Protective Headwear for Industrial Workers-Requirements.Continue Reading