Industrial electrical equipment belongs to the category of complex devices. Its functioning poses a threat to human health and life. To avoid accidents, safety precautions are provided when working with electrical equipment.
Electric shock
Such a danger is created if safety precautions are violated during the operation of electrical equipment. Electric shock is possible through direct contact with the conductive elements of the unit, which are energized. The passage of the discharge through the body is accompanied by biological, electrolytic, thermal effects. The latter manifests itself in the form of burns on certain parts of the body, heating of blood vessels and blood. Biological effects are accompanied by irritation of body tissues, which, in turn, can lead to the cessation of the functioning of vital systems. The electrolytic effect is manifested in the decomposition of blood.
Consequences of the defeat
The result of the current depends on its voltage and magnitude, duration and frequency, path, as well as the general condition of the body. According to studies, a tangible (threshold) is 1 mA. With increasing current, painful muscle contractions appear. With the passage of a current of 12-15 mA, a person loses the ability to control his muscles and can not tear himself away from the damaging source on his own. Such discharges are called non-releasing. With a subsequent increase in current, there is a high probability of cardiac fibrillation (convulsive contraction). A discharge of 100 mA is considered fatal.
Electrical Safety: General Information
Access to devices can be obtained by trained professionals. A fitter or electrician for the repair and maintenance of electrical equipment must pass an appropriate test of knowledge of PTE and PTB in the qualification commission. Other specialists gain access to the units only under the supervision of responsible persons. Regardless of qualifications, employees must distinguish between electrical safety signs.
Installation Inspection
An electrician for repair and maintenance of electrical equipment must not perform any actions involving contact with conductive parts until the unit is turned off. If an emergency condition is detected, immediately disconnect the elements and report the situation to the responsible person. During the inspection, special attention should be paid to the presence and serviceability of protective grounding (grounding) of buildings, casings, frames and other things. If a hand touches non-conductive elements (for example, to determine the heating level), a current effect is detected, there is a violation of insulation and ground faults. In such situations, you must immediately disable the installation.
Change fuse inserts
Safety precautions when working with electrical equipment contains a requirement in accordance with which the replacement of burned-out elements is carried out with the voltage removed. If it is impossible to ensure the fulfillment of this condition in exceptional situations, it is allowed to perform actions with the load off. The danger in this case is that during the replacement process, the fuse insert may blow out (especially in the event of a short circuit). In this case, there is a danger of electric arc ejection. This operation is performed using insulating mites. At the same time, there should be dielectric gloves on the hands , and the eyes are protected by special glasses.
Special cases
Safety precautions during the repair of electrical equipment prescribes the mandatory removal of voltage before performing any action. However, there are some exceptions to the rules. In some cases, it is allowed to carry out small-scale work to correct problems with unaccepted voltage. Certain conditions must be met with units up to 380 V. Access to them is obtained by specialists who have 3 access control groups for electrical safety. At the same time, one more person having a 4th or 5th group should be present.
Fire Prevention
Safety precautions when working with electrical equipment provides requirements for the tools used. In particular, it is forbidden to use steel hacksaws, rulers and other devices with which you can accidentally cause a short circuit. Tool handles must be securely insulated. The troubleshooting specialist must be on a non-conductive base. Similar requirements are provided by safety measures during the installation of electrical equipment.
Security
All activities, including testing of electrical equipment, are carried out in accordance with the requirements of the relevant sanitary rules and norms, which are approved by the deputy. Chief Sanitary Doctor and GOST. According to these standards, the intensity of the magnetic field should not be more:
- electrical component in the frequency range 100 kHz-30 MHz - 20 V / m, 30-300 MHz - 5 V / m;
- in the magnetic component in the range of 100 kHz โ 1.5 MHz - 5 A / m.
The measurement of the intensity of the electromagnetic field is carried out by the IEMP-1 device. Functioning generators must be placed in special rooms. It is allowed to place HF installations intended for heating dielectrics and metals in general production shops. In this case, certain conditions must be observed. In particular, maximum permissible radiation levels should be provided at workplaces and exposure to persons who do not service these units should be excluded. During the heat treatment of dielectrics and metals, it is necessary to equip exhaust ventilation. Air inlets must be made of non-magnetic materials to prevent them from being heated by RF currents.
Personnel protection
It is achieved:
- Reducing the intensity of the radiation source of the magnetic field.
- The use of personal protective equipment, as well as automatic warning alarms.
- Shielding or removing workplaces from radiation sources using remote control.
- The creation of rational regimes for the functioning of equipment and staff activities.
In units for induction heating, as a rule, common shielding is used. In this case, the quenching inductor and control panel are taken out from the screen, or block shielding is created. In the latter case, the capacitor element is in the form of a metal mesh or chamber. The screen of the transformer is made according to the type of steel casing. The element of the melting or heating inductor is in the form of a metal movable chamber. During heating, it lowers and rises at the end of the operation. The screen may also be in the form of a fixed camera equipped with a door. It opens only for the period of replacement of the heating element.
Operational maintenance of electrical equipment
This activity includes:
- control over the operating mode and condition of the devices;
- transfer of information about the operation of equipment.
In the event of instrument malfunctions, operating personnel must take measures to eliminate them. To ensure the stable functioning of the equipment, preventive and repair work should be carried out. All of the above and other events that are organized in existing units must be performed in safe conditions. They are determined in accordance with the PTB approved by the Department of the Ministry of Electrification and Energy.
rules
They define the requirements for the personnel who are working (repair of electrical equipment and other activities). Employees should have a clear idea of โโthe likely threat when in contact with the units, be aware of and be able to apply the safety rules to the extent commensurate with the task being performed. The staff should know how the installation of electrical equipment, commissioning, use, as well as understand its device. Specialists should be able to provide first aid to victims, namely: indirect cardiac muscle massage and artificial respiration. At training events, electrical safety signs are studied, among other things. The PTB provides additional provisions. They relate to the operation of a variety of electrical installations, which include switching devices, electric motors, generators, overhead and cable lines, batteries and so on. The PTB also includes applications, including instructions for the provision of first aid to persons affected by electric shock, and in other cases. Compliance with the rules is mandatory for all employees, regardless of their position.
Qualification
Specialists study the rules and pass them in accordance with their position, after which they are assigned a specific admission group. There are 5 of them in total. The first are persons who are not related to electrical personnel. These employees must receive appropriate training. The fifth group is assigned to the operational repair, duty and repair personnel. Specialists under 18 are allowed to assign the 1st or 2nd group, not higher. Trainees of institutes and technical schools are allowed to get the 2nd group after the experience of their work is at least a month. After three months of activity in the specialty, they may be assigned the 3rd group of tolerance for electrical safety. The qualifications obtained are indicated on the certificate. This document must be in place when performing work. The certificate also includes additional information, if available. For example, if a specialist is allowed to perform other work (climbing, testing, energizing, and so on), this should be indicated in the document. Employees with special secondary or technical higher education? The 2nd group can be assigned without experience, the 3rd after 3 months of activity with the 2nd group, the 4th after 3 months from the 3rd, and the 5th after six months from the 4th. In addition to the specified period of work, to obtain the fourth and fifth groups it is necessary to know the layout of electrical installations, to be able to organize the production of work in compliance with safety. To get the 5th group, an understanding of what is caused by the requirements established in each paragraph of the PTB is also required.
Important point
Safety instructions developed by enterprises should not contradict the above rules. They must be approved by the organization in agreement with the trade union committee. It is strictly forbidden to perform tasks, orders and instructions that contradict established requirements. Activities that are provided for in the rules to some extent hedge each other and are not duplicate. In this regard, failure to comply with certain paragraphs may result in accidents.
Responsibility
The rules are binding on all enterprises in which electrical equipment is operated. For their violation, the persons responsible for this will be brought to administrative, criminal or disciplinary liability. Work classified as hazardous is permitted to persons over 18 years of age. This activity requires special knowledge, experience, attention. Such activities, for example, include activities carried out under voltage: cable (associated with hot bitumen, lead, troubleshooting and welding of cables in polyvinyl chloride and polyethylene sheaths), soldering using lead and alloys containing it, activities with explosive compounds, earth work that is carried out continuously and systematically, and so on.
Electrical Safety Signs
They warn of a threat that comes with approaching live units. They may also indicate places where there is no likelihood of electric shock. Electrical safety signs are classified as follows:
- Pointing.
- Prohibitory. They indicate the inadmissibility of turning equipment on or off. This prevents erroneous voltage supply during operation. Such signs include: "Do not include. Work is underway"; "Danger! Do not enter without protective equipment!"; Do not turn it on again! Work under tension! ".
- Warning. They indicate that a person is approaching a dangerous distance to the conductive elements: "Stop! High voltage!"; "Do not fit! Kill!".
- Prescriptive. These signs are used to indicate work areas in installations and a safe path to them.
Signs can be portable or stationary.
Control
The rules establish the procedure for admission to electrical installations of persons who do not carry out their maintenance. These employees are allowed to carry out certain activities only in the presence of personnel with the appropriate qualifications. In this case, the person accompanying the employee is obliged to monitor the safety of the latter, to warn about the prohibition of approaching the current-conducting elements. For business travelers, a personal certificate is filled in, which contains information about the verification of knowledge of the rules. The certificate also indicates the admission group. Upon arrival, business travelers must be briefed. In the classroom, they learn safety precautions taking into account the peculiarities of the electrical equipment with which they will work.