By Jim Phillips, P.E.
International Chairman IEC TC 78
As the International Chairman of IEC TC 78, a frequent question that I receive is “What is IEC TC 78?”
IEC is the acronym for the International Electrotechnical Commission based in Geneva, Switzerland. TC 78 standards for Technical Committee 78 which is the Live Working Committee. This committee is responsible for over 40 different International Live Working standards and documents and is represented by 42 countries via National Committees which includes 136 individuals known as Experts. Before I go any further, let’s back up a few steps first.
Founded in 1906, the IEC (International Electrotechnical Commission) based in Geneva, Switzerland, is the world’s leading organization for the preparation and publication of International Standards for all electrical, electronic and related technologies.
IEC provides a platform to companies, industries and governments for meeting, discussing and developing the International Standards they require.
All IEC International Standards are fully consensus-based and represent the needs of key stakeholders of every nation participating in IEC work. Every member country, no matter how large or small, has one vote and a say in what goes into an IEC International Standard.
The IEC is one of three global sister organizations (IEC, ISO, ITU) that develop International Standards for the world. When appropriate, IEC cooperates with ISO (International Organization for Standardization) or ITU (International Telecommunication Union) to ensure that International Standards fit together seamlessly and complement each other. Joint committees ensure that International Standards combine all relevant knowledge of experts working in related areas.
From the official scope of IEC Technical Committee 78 it is:
To prepare International standards for tools, equipment and devices for utilization in Live Working, including their performance requirements, care and maintenance.
Excluded: Work practices and methods for Live Working.
To prepare technical publications related to the utilization of tools, equipment and devices on, and in the vicinity of, live parts of electrical installations and systems.
In simple terms, if it is a tool, equipment etc. for use in Live Working, TC 78 is likely the place where you find a standard for it.
Live working sometimes referred to as Live-line working is where the maintenance of electrical equipment and systems is performed while the equipment is energized – this includes transmission voltages in the 100’s of thousands of volts – INCLUDING BAREHAND WORK!
The first techniques for live-line working were developed in the early 1900’s and both equipment and work methods were later refined to deal with increasingly higher voltages. In the 1960s, methods were developed in the laboratory to enable field workers to come into direct contact with high voltage lines. Such methods can be applied to enable safe work at the highest transmission voltages.
Live Working methods can be applied to enable safe work at the very highest transmission voltages. “Bare-Hand” and/or ‘Live-Line” is the method whereby a worker is placed at the same potential as, and works directly on energized conductor or equipment. The transfer of the worker to conductor potential may be accomplished through the use of insulated ladders, live line rope, insulated EPV personnel buckets or helicopters.
The live-line barehand technique is used to work high voltage lines (generally 115 kV and higher) while they are “live.” Since insulating gloves are not available for these voltages, the technique of bare-hand live line work has been developed in which the worker is bonded to the line, working, insulated and/or isolated from ground and all other objects at a different potential.
With the metallic mesh clothing bonded to the conductor, the lineman can work protected inside the electrical field. Conductive Clothing creates a Faraday cage effect that places a linesman at the same potential as the conductor. Metallic mesh clothing? Yes, and IEC TC78 has a standard for it – and many other standards as well!
Below is a list of the standards and documents that are developed and maintained by IEC TC78.
IEC 61482-1-1:2009 ED1 – Live working – Protective clothing against the thermal hazards of an electric arc – Part 1-1: Test methods – Method 1: Determination of the arc rating (ATPV or EBT50) of flame resistant materials for clothing
In addition, there are several new international standards and technical reports that are currently under development.
So, what is IEC TC 78? To sum it up, a very busy group with experts from many countries around the world dedicated to developing standards for safer live working for tools, equipment and devices. With live working, the electrical power transmission and distribution system, can experience fewer outages and maintain better reliability.
About Jim Phillips: Electrical Power and Arc Flash Training Programs – For over 30 years, Jim Phillips has been helping tens of thousands of people around the world, understand electrical power system design, analysis, arc flash and electrical safety.
Jim is Vice Chair of IEEE 1584, International Chairman of IEC TC78 Live Working and Steering Committee Member – IEEE/NFPA Arc Flash Collaborative Research Project. He has developed a reputation for being one of the best trainers in the electric power industry. Learn More
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