|Hot line maintenance began when
disconnect sticks were first used to open energized disconnect switches. Even though
this operation proved that long, dry poles could be equipped with fittings which would
enable linemen to work with safety on energized lines, many years passed before sufficient
interest was aroused in the hot line idea to use these tools for any operation other than
use of hot line maintenance tools is sometimes considered a recent development in the
electrical power industry, forerunners of modern hot line tools made their appearance as
far back as 1913. The earliest available picture of these tools is the accompanying
photograph taken in 1914. The tools shown were manfacured in Wapakoneta,
Ohio. These intial tools were homemade, crude and bulky; however, they sparked the
development of our present efficient and refined tools.
|In the year 1916, a tool that was known
as an "electrical hook" was introduced in Atlanta, Georgia. This was
essentially a spring-type clamp for tapping energized circuits. The electrical hook
necessitated a hot stick for installation purposed, and its use suggested additional
tools which were soon developed for grounding and jumper service, applying parallel groove
clamps, handling conductors, pulling cotter pins and manipulating tie wires. There
soon followed a hack saw, a hot line "cum-a-long," and saddles which could be
attached to poles for supporting certain tools.
In the year 1918, at Taylorville, Illinois, the Tips Tool Company began manufacturing hot line clamps, grounding clamps and clamp sticks. A few years later, the same Company introduced the hot line tree trimmer, wire tongs, long sticks, wire tong saddles and numerous hand tools. Thes tools suggested the idea of universalhand tools with interchangeable heads which soon came into practical use. The Tips Tool Company also introduced the slide support, and probably the first tool for handling dead ends without the necessity of using rope blocks.
|The Tips Tool Company was purchased by
the A.B. Chance Company in 1937 and the manufacturing facilities were moved to Centralia,
Missouri where the research and development of hot line tools has been accelerated.
Considerable credit should be given to the farsighted individuals who visualized
the time when power circuits could not be easily de-energized while insulators, cross
arms, poles and other equipment were beingreplaced. They realized that duplicate
circuits for service purposes would be entirely too costly, and that the rapid growth for
operating home appliances, farm equipment, etc., would demand that electrical power be
maintained without interruption. Linemen were perhaps the first group of men to
realize this need. In almost every case, it was the linemen who prompted development
of the various hot line tools which eventually led to the present universal practice known
as "hot line manitenance."
|Hot line tools were first accepted for work on lines up to 34kv but many linemen were hesitant to perform hot stick operations on this voltage. Because of this fear, many companies restricted hot line manitenance to 22kv, and less. As linemen began to realize that the use of hotline tools always kept them at a safe distance form energized lines, they began to lose their fear of performing this work, and restrictions wer gradually relaxed until by 1930 several companies were permitting hot line operations to be performed on 66kv lines. This soon rose to 110kv until in the late Thirties the astonishing news was circulated that a West Coast line of 220kv had been successfully worked "hot." Another mile postwas passed in March of 1948, when O.G. Anderson and M.R. Parkin, Hot Line Tool Specialistsof the A.B. Chance Company, changed suspension insulators on the 287kv Hoover Dam, Los Angeles Line, using tools specially designed for the job. The A.B. Chance Company is now (1954) building tools that will successfully handle the 345kv lines, presently under construction. At the present time there are few jobs that cannot be performed hot, and about the only limitation to this type of work results form the type of construction employed.||
A number of wood species are used in the manufacture of hot line tools. These woods ar Sugar Pine, Sitka Spruce, Douglas Fir, Redwood White Oak, Red Oak, Maple, Hickory and some Philippine Mahogany. Because of its light weight, strength, and excellent electrical properties, Sitka Spruce has become the most popular of these woods. Early methods of preparing the wood poles consisted of rubbing with paraffin wax, immersing in cottonseed oil, coating with shellac and shellac base compounds, etc. Later, shellac began to give way to various synthetic resins. Extensive high voltage experiments on wood and tubular plastic handles were begun at the Chance Laboratories in 1945 and later, in 1946, extended to include plastic covered wood. Today plastic coated hot line tools are extensively used.
Weight is an important factor in hot line work, as fatique must be kept to a minimum. Therefore, considerable atttention is given to the tools lighter, stronger, and safer. In 1947 the A.B. Chance Company introduced heat-treated aluminum alloy heads and other fittings for hot line tools to augment the light weight Sitka Spruce tools. In designing a hot line tool, the welfare of the linemen is the important consideration. Insulation characteristics and strength of the tools are of major importance, as the linemen's safety depends upon these things. The ease with which the tool handles, the relief from fatigue, the manner in which it operates when engaging a tie wire, strain clamp insulator, or conductor are also important considerations. Chance hot line tools are given field trials, after laboratory tests prove them to be electrically and mechanically sound. This testing is performed under actual conditions by men who are specialists in hot line maintenance work. Most hot stick design work at the present time is devoted to refining equipment and keeping abreast of line construction practices. Plastic coatings have provided greater wear resistance, and have reduced tool maintenance considerably, as the plastic retards moisture absorption and , in general, probides the linemen with a better, safer tool with which to work.
Engineers are beginning to desgn new lines, and rebuild many old ones, to favor hot line work as a more desirable and safer way of performing line maintenance into consideration hot line maintenance requirements help to build lines that are considerably more economical to maintain, and require a minimum variety of tools for servicing.
The tool manufacturer, the hardware manufacturer, and construction engineers are beginning to work together to coordinate tools, hardware, and transmission lines for maximum efficiency. The safety engineers and operating men in the electrical industry, with the help of hot line tool demonstrators, have established schools for training the "elite" of the pole climbing fraternity---the hot line crew. The combined teamwork of all these groups is rapidly developing lines and line crews to the point where power shut-downs for repairs are the exceptions rather than the rules.
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