Protection against electric shock: general safety precautions and personal equipment

It's hard to imagine life without electricity. Its nature is not fully understood, but this does not prevent the use of electrical devices and devices everywhere. The flow of charged particles in a conductor is a force that can bring not only benefit, but also harm, especially if the rules of protection against electric shock are not followed.

General security measures

The most effective means of protecting against electric shock is to lower the operating voltage of the equipment. The stratum corneum of the skin, unlike other tissues of the body, has high resistance. Penetration of human skin with direct current occurs at a voltage above 50 volts. The amount may vary depending on the thickness of the epidermis and other factors.

It is believed that devices with an operating voltage below 42 V are quite safe. Voltage up to 12 V, like in a pocket torch, guarantees maximum safety. A household power tool such as a screwdriver can operate at 36 V. Reduced voltage is used in rooms with increased danger. In everyday life, such a measure of protection is rare.

. When working with current, the following precautions are applied:

• insulation;
• restriction of human access to installations operating with electricity;
• automatic blocking devices that cut off the supply of energy in emergency situations;
• lowering the operating voltage;
• grounding;
• personal protective equipment;
• marking and signaling.

The main means of protection against electric current are described in GOST. Let's take a closer look at each of the methods.

Network solutions

An effective way to reduce the risk of injury is to smash one large electrical network by making several smaller ones. The operating voltage remains the same, but the capacity of the network decreases, and the total insulation resistance increases. For this, dividing transformers are installed, to which the equipment is already connected. This solution is relevant for networks with voltages up to 1000 volts.

Conductive parts are necessarily insulated, that is, covered with a layer of dielectric, if human contact with them is provided. The protective coating can be plastic, varnish, paint, rubber or ebonite. Double insulation is the second layer of polymerwhich performs a protective function if the basic insulation is damaged. It is obligatory to carry out control measurements of resistance. There are also armored communication cables and reinforced insulation.

Equipment with high voltages (> 1000 volts) is particularly dangerous. Defeat is possible not only as a result of contact with the phase, but even with a close location close to conductive elements, therefore such installations must be fenced, and access to them limited. Lifting wires to a height inaccessible to an outsider, or laying cables underground are typical techniques.

Grounding and RCD

Those parts of the mechanisms that should not be energized are grounded. A conductor, usually steel wire or reinforcement, is led to parts of the enclosure that may be energized. The other end of the grounding conductor is shorted to ground.

One of the options is to dig in a metal blank, which is called a ground electrode, into the soil, and weld reinforcement or wire to it. The number of earthing switches should be higher if the network is high-voltage. In this case, the conductors are dug in around the perimeter of the working platform or otherwise spread them. This is necessary so that the charge effectively drains into the soil, while a current of less strength will pass through the human body or will not pass at all.

It is better to choose clay or wet soil as it has a lower resistance. Underground pipelines, communication channels, and building fittings are also used as a ground electrode.

Disconnecting automatics is a device that quickly breaks the circuit when a dangerous situation arises, for example, when a phase is shorted to the device casing. Power off must occur after at least 0.2 seconds.

Individual protection

Protective equipment against electric shock is divided into several types: basic insulating, additional, fencing, safety. Fixed assets prevent the breakdown of voltage of the declared value for a long time. Conductive parts can be touched:

• voltage meters;
• rubber insulating clothing;
• dielectric rods and non-conducting clamps;
• tool with dielectric-coated handles.

Additional protection alone does not protect against electric shock. It works in conjunction with other methods of protection. This class includes insulating mats, boots, galoshes and coasters.

Guards restrict access to electrified items of equipment. These include warning posters and signs, temporary grounding, barriers and portable shields. Protective personal protection includes:

• safety systems and belts;
• goggles, helmets, gloves;
• gas masks and respirators;
• installer's claws;
• shielding devices;
• work suits.

These means provide protection from other influences and factors, for example, from falling from a height, burns, mechanical damage.

Protective insulating clothing

Dielectric gloves come in two- and five-fingered, as well as seam and seamless. They must be at least 30 cm. They are worn over work clothes and regular fabric gloves. The presence of damage, cracks and punctures must be determined before using such equipment. To do this, the glove is rolled into a tube from the neck to the fingers, while carefully examining. Do not roll up the edges of insulating gloves.

Insulation carpets are used only indoors. It is permissible to use them in dry weather in open installations. Rubber is used as a regular rubber, as well as resistant to oil and gasoline. The upper side is corrugated, the depth of the notches is up to 3 mm.

Dielectric Shoes (boots and galoshes) on damp ground and in the rain is not used. The boots have a flap to drain the charge. They are taller than galoshes and are considered the best protection option. Galoshes are used only when working with low-voltage equipment. Insulating clothing is tested once a year.

Work rules

Before any action with the electrical installation, you must check the absence of voltage on it. It is also necessary to install warning posters indicating the work being carried out. All actions are carried out using measuring clamps and pointers.

If it is not possible to turn off the power, then they work without removing the voltage, which is associated with an additional danger. Such work is carried out with special safety requirements. At voltages up to 1000 volts:

1. The tool is used only dielectric; in addition, the screwdriver must have an insulated rod. If such a tool is not available, then insulating gloves are used.
2. Protect live conductors with which it is not planned to work.
3. Installers must wear galoshes and stand on a dielectric stand or rubber mat.

At voltages above 1000 volts, work can only be done with the voltage removed. It is forbidden to touch the insulators of towers and installations with the power on.