From the history of electrical safety

The first idea of ​​the danger of an electric current, that an electric discharge affects a person, became apparent in the last quarter of the 18th century. One of the first detailed descriptions of this action belongs to Marat, a prominent figure in the Great French bourgeois revolution of 1789-1794. The Englishman Warish, the Italians Galvani and Poletto and a number of other scientists have established that a person is discharged by a discharge obtained not only from a source of static electricity but also from an electrochemical cell. However, none of the researchers mentioned the danger of this action on humans. For the first time this danger was invented by the inventor of the world's first electrochemical high voltage voltage source V. V. Petrov.

Having created a well-equipped physical laboratory at the St. Petersburg Medical-Surgical Academy, Petrov began to systematically study the effect of electric current on the animal and human organism, as well as on the development of measures to protect a person from current. It is natural that it was in this academy that a number of interesting studies were carried out on the mechanism of interaction of an electric current with a man, which, however, was not only protective, but also therapeutic. In 1863 the Frenchman Leroy-de-Mercure gave a description of the industrial electric shock on direct current, and in 1882 the Austrian scientist S. Jellinek described the first electric shock with alternating current.

From the very first issues, the Russian magazine "Electricity", founded in 1880, began a systematic publication on its pages of reports of accidents caused by electric current. Similar publications began to appear in other Russian technical journals. For example, in the journal "Elektrotehnik" only for the period from 1898 to 1903 data are given about more than 20 electric trauma, accompanied by a heavy outcome.

Already in the first years of the development of electrical engineering, a lesser danger of direct current was clearly identified. Very vividly wrote about this VN Chikolev:

"When you touch a conductor with a constant current, then at the moment of touch you will feel a tremor, then you feel little or nothing when the current flows through you; Only when you take your hands off the guides, will you again experience the same concussion. I myself many times deliberately touched the guides to dispel this fear, always quite sure that nothing will happen to me. A completely different meaning is the alternating current (or the current of a constant direction, but of a variable force), which changes its direction and force from 5000 to 10,000 times per minute. Touching such conductors really produces tremendous tremors. The fnznolognoe action of a direct current can be compared to a strong mechanical thrust or impact, which is dangerous with a very huge shock voltage. But how many times weaker the shocks can be that will shock you 10,000 times a minute, so that you will experience a terrible frustration, this is the consequence of touching the conductors with alternating current. Thus, the danger does not exist from the strength of the current that passes through you, but mainly from whether the current will be constant or alternating. For city sewers, conductors with direct current are possible, in which case there is no fear of danger. "

In an even more categorical form, VN Chikolev outlined this idea in his article "The History of Electric Lighting," where he wrote:

"With constant currents, no matter what strain they reach, impossible unfortunate, sometimes fatal cases, as with alternating currents.

VN Chikolev believed that the electric current is dangerous not only in magnitude, but also in the character of its growth, the latter, in his opinion, which poses a great danger. Thus, he foresaw the basis of the modern concept of the mechanism of electrotrauma.

The danger of electric shock during the operation of electrical equipment arose, strictly speaking, only as a result of the wide application of alternating current at a frequency of 50 Hz. However, there was no detailed information on the mechanism of the action of electric current on man at that time. Simple and effective protective measures were also unknown. Therefore, there is every reason to believe that electrical safety as a problem arose in the last quarter of the XIX century and it was at this time that the first attempts at its reasonable resolution were included.

The first rules of electrical safety.

In the 90 years of the last century, on the initiative of PD Voynarovsky, the development of rules for the use of high voltage electrical devices (up to 3000 V) began. This work was completed in early 1898, and on July 8 of the same year, the first official legislative documents were approved, which were both a safety precaution in the design and operation of high-voltage installations and high voltage technology. They were called "Temporary rules for underground drainage of high voltage wires up to 3000 V (from 250 V AC and from 450 V DC)" and "Provisional rules for the production of works and monitoring of the network of underground sewerage of high voltage wires." A report on the rules was made at the First All-Russian Electrotechnical Congress, Prof. P.D. Voinarovsky. In the discussion of the report, hygienists participated. It was adopted a very progressive proposal for a thorough investigation of all cases of electric shock and lightning, and if the injury resulted in the death of the victim, it was recommended that an autopsy and thorough pathoanatomical examination of the victim's body be recommended. The decisions made by the Congress regarding the use of electrical installations and networks attracted attention to the prevention of electric trauma.

The development of the rules continued even after the congress. The rules were expanded and supplemented taking into account the results of the new research on electrical engineering that was being carried out at that time in Russia. In the period between the first and second electrical congresses in the field of electrical safety, a lot of work was done.

The Second Congress on the reports of PD Voinarovsky and PS Osadchy adopted a series of fundamental decisions relating to the safe maintenance of electrical installations. Thus, for a low voltage, a voltage below 250 V was applied to the ground, for the raised voltage limits of 250-750 V, and for a high voltage, above 750 V. The progressive role of PD Voinarovsky and PS Osadchy was that, Suggesting the normalization of voltage limits, they also took into account the need to supply electrical equipment with protective means, thereby creating the basis for electrical safety.

In 1911 - 1912 years. In St. Petersburg, several electrical injuries occurred, from which the personnel who served the electrical equipment of theaters and cinematographs suffered. The circumstances of the occurrence of these injuries attracted the attention of the electrotechnical community and were examined in detail in the electrical section of the Russian Technical Society. As a result, special safety rules were developed for servicing electrical equipment for entertainment companies.

The contribution of Russian scientists to the development of electrical safety problems. AA Smurov did a lot in this respect. Interest in electrical safety issues arose in his student days, which was reflected in his diploma project. Then he continued these works at the Department of High Voltage Engineering of the Electrotechnical Institute. At this department, where he was elected in 1919, A. A. Smurov investigated the earthing devices, determined the dangerous effect of power lines on communication wires, sought the most advantageous safety views of neutral modes, and created reliable switchgears. Together with him, these studies were conducted by SA Khaetsky, NN Belyaninov, KS Arkhangelsky, and others.

Most fully named works were reflected in AA Smurov's monograph on electrical safety, one of the first in the world literature written on this topic. The names of its three main parts - "Danger of high-voltage currents for life", "Danger from high-voltage currents on power transmission lines and measures to protect against this hazard during operation and repair of lines", "Influence of power lines on neighboring low-current installations" - give Representation about the issues discussed.

The results of the research of AA Smurov's school have not lost any scientific significance even now. This particularly applies to the determination of the electrical resistance of the human body.

AA Smurov was the first to establish the nonlinearity of the electrical resistance of a human body - this is the most important characteristic used in determining the damaging values ​​of voltages and currents.

For the sake of fairness, we note that the monograph A. Smurov at the time of its publication was not the only difficulty on this topic. A year before it saw the light of IG Freiman's research "Radnotekhnika", referring to the problem of electrical safety at radio stations. This study is devoted to the dangers and hazards when working on radio equipment, as well as protecting people from possible electric shock. IG Freiman considered the whole complex of occupational safety issues for persons serving radios, pointed to the possibility of not only acoustic and electric injuries, but also the harmful effect of electromagnetic field radiation on vision. The merit of IG Freiman is that he first emphasized the close and direct relationship between electrical safety and reliability of equipment. Perhaps, precisely because at the dawn of the development of mass application of radio engineering, one of its founders strikingly formulated the main provisions of safety engineering, the number of electric trauma was not very high for work on radio engineering installations.

A major contribution to the development of effective methods for the preventive testing of electrical equipment and the solution of the whole range of problems combined by the concept of "electrical safety:" was made by labor safety departments of the Leningrad Electrotechnical Institute, the Moscow Power Engineering Institute, the Moscow Institute of Agriculture Electrification, the Moscow Institute of Railway Transport, and the All-Union The Research Institute of Electrotechnics, the State Inspectorate for Industrial Energy and Electrical Inspection, and its inspections in the energy distribution of energy associations, the Leningrad Institute of Labor Protection of the All-Union Central Council of Trade Unions, ORGRES and a number of other organizations. The mere enumeration of these institutions and organizations makes it possible to judge the scope with which work on electrical safety was already conducted at that time.

In the 30s, an extremely important event for the development of electrical safety occurred - the Rules for the Technical Operation of Electric Power Stations and Networks are being developed and implemented. After the release of the Rules, a number of organizational arrangements for safety precautions, especially preventive testing of electrical equipment, become mandatory for power plants and networks of all departments.

By the end of the 1930s, the development of the "Rules for the Technical Operation of Electrical Equipment of Industrial Enterprises" was included. The regulation of the operation of electrical equipment, including its acceptance, played a very important role. Suffice it to say that even during the difficult years of the war, when the equipment was operated with overload, the length of the temporary networks has increased and many young, inexperienced workers have come to the industry, the electro-traumatism has not increased.

Of great importance for increasing the electrical safety in industry and power systems are the "Rules for the Technical Operation and Safety of Maintenance of Electrical Installations of Industrial Enterprises" issued in 1961 and obligatory for all enterprises and departments and published in 1969 a new, revised edition of the "Rules for the Technical Operation of Power Plants and Networks ".

Familiarized with the measures for electrical safety contributed to the large-circulation books of VI Korolkova, AI Kuznetsov, BA Knyazevsky and others, and, most importantly, books highlighting the special focus of electrical safety. These include the book of GS Solodovnikov. This is also facilitated by materials published in leading electro technical journals, including discussions on contentious issues. Regularly (since 1959) a collection of scientific works of labor protection institutes of the AUCCTU is published, in which a large place is given to research on electrical safety conducted at the Leningrad Institute of Labor Protection. Significantly improved the accounting and investigation of accidents after the department of labor protection of the AUCCTU approved in 1959 and 1966. Relevant provisions.

The accumulated experience of applying the rules of operation and safety shows the possibility of their processing and some reduction. Reducing the amount of information that operational personnel must know will undoubtedly lead to more precise fulfillment of the really necessary requirements, and consequently, will reduce accidents and accidents classified as "personnel errors". The possibility of reducing the volume of rules appeared in connection with the growing introduction of automation in the management of electrical equipment and networks.

Manoilov VE Fundamentals of Electrical Safety