What is Live-line Working?

Live-line working, or Hotline work, can be defined as the maintenance of electrical equipment while still energised. This requires the worker to enter into contact with energised parts, or enter the electrical hazard area, either with part of his body or with the tools, equipment, devices or materials that he is handling.

Live working should only be performed by suitably trained, fully qualified workers, equipped with specially designed tools and equipment suited to the job, in accordance with established, written work procedures and methods.

There are essentially three live-line working methods:

Image supplied courtesy of MAESSA.

History

Live line tools and techniques date back to the early 20th century. It is reported that by the 1910s a number of crude, home-made tools, fitted to the end of long, dry wooden poles, were used for a number of purposes in addition to opening energised disconnect switches. In 1918, the Tips Tool Company, of Taylorville, Illinois started manufacturing hot line clamps, grounding clamps and clamp sticks, soon to be followed by tree-trimming hotsticks, wire tongs, wire tong saddles and a range of hand tools. This led to the development of interchangeable universal hand tools that could be fitted to the end of a hotstick. In 1937 the Tips Tool Company was acquired by the A.B. Chance Company, which has continued to produce and develop a broad range of tools and equipment, suitable for increasingly higher voltage levels, at its manufacturing and research facilities in Centralia, Missouri.

The introduction of Epoxiglas tools in1959 marked a significant breakthrough, since before that the poles were made of solid wood, which had to be kept dry and required considerable physical strength to handle. Epoxiglas poles consist of a hollow fibreglass-reinforced rigid unicellular epoxy resin tube filled with polyurethane foam. This product and its manufacturing process were developed by a plastics engineer at A.B Chance

The major highlights in the development of live-line working equipment, in which A.B. Chance played a central role, include:

1964	Kobbeco, the A.B. Chance representative in Spain since 1964, assisted in the introduction of live-line working techniques and pioneered the supply of hotline tools into Spain.

1969	Live line work was performed for the first time in Spain by electrical contractor Cobra in 1969.	1973	Followed in 1973 by Elecnor and a number of other contractors and utilities.
Images supplied courtesy of Cobra Instalaciones y Servicios S.A. and Elecnor S.A.

Kobbeco, which also pioneered the supply of rubber glove equipment and insulated aerial devices in Spain, is currently the distributor for Spain, France and Portugal of insulated aerial devices and digger-derricks for hotline work manufactured by Terex Utilities.

Terex Utilities was founded in 1945, with the introduction of the Tel-E-lect digger derrick, followed by the first aerial device in 1950. Ever since, the brand has followed a policy of continuous improvements to enhance the ease of operation, reliability and safety of its products. An example of this is the development of the universal joystick control, allowing precise control of the boom with a single lever.

This innovation by TEREX-TELELECT has proved a valuable contribution to the industry, as evidenced by the fact that joystick controls have been widely adopted by other manufacturers.