Where work is connected with electricity, there is always the possibility of electric shock to a person. The influence of adverse environmental conditions is exacerbated by the fact that the human body is able to provide little resistance. And if the room has high humidity, then the likelihood of electric shock increases, since the sweat of a person conducts it very well. There is a classification of premises for the danger of electric shock. GOST provides for three classes.
Classification of premises without increased danger
Such rooms have normal temperature and humidity, there is no dust, floors are made of materials that do not conduct current (usually wooden), there are no grounded objects or their number is minimized. These rooms allow the use of electrified tools with a voltage of 220 volts. Classification of premises by the danger of electric shock includes:
- rooms for work of administrative and managerial personnel;
- computer centers;
- utility, tool and control rooms.
Classification of hazardous areas
Such premises are characterized by:
- relatively high humidity exceeding 75%;
- temperature with a constant or periodic mark on the thermometer 35 degrees;
- conductive dust, which covers the wires and internal surfaces of electrical equipment;
- conductive floors. They are made of materials such as metal, brick, reinforced concrete, or can simply be earthy.
The room is classified as hazardous if at least one of these characteristics is present. Classification of premises by the danger of electric shock of this class extends to the production premises of enterprises associated with vehicles, areas for maintenance and repair, thermal, welding compartments.
Classification of hazardous areas
They differ:
- excessive air humidity, which reaches 100%, due to which condensation forms in the room;
- the presence in the room of chemical aerosols that conduct current, as well as vapors, liquids and gases, which gradually destroy the insulation and conductive parts of electrical equipment.
A room affected by mold is also considered especially dangerous, since it, along with chemical gases, can also destroy the insulating layer. Moisture must not enter the building from the outside. Constant rainfall will make it especially wet, and, therefore, extremely dangerous. Especially dangerous is such a room, which is characterized by two or more conditions at the same time. This classification of premises for the danger of electric shock relates to:
- storage facilities in which fuels and lubricants and dangerous goods are stored;
- battery and paint compartments;
- washing and steaming chambers.
On the territory with the placement of external electrical installations on it, the classification of premises according to the danger of electric shock applies. PUE (Electrical Installation Rules) contain the basic requirements that electrical installations must comply with. The territory can be fenced or not. It is necessary that the electrical equipment has reinforced insulation.
In cases of electric shock, it is necessary to exert an effect on the flame (when ignited) by any extinguishing agents. So is ordinary water. But here there are drawbacks. Since water has increased electrical conductivity, it should not be used when igniting electrical installations with high voltage. In the case of extinguishing oil products, the situation is complicated by the fact that they continue to burn on its surface. In these cases, chemical foam and powder formulations are used.
In order to prevent electric shock, it is always better to minimize the risk, namely:
- Use protective guards around hazardous areas. Such protection will help to avoid close contact with live objects and, as a result, to protect against electric shock.
- Using a lock will help to avoid an accident if current is limited due to equipment malfunction.
- To avoid emergency situations, use portable grounding conductors, especially if work is carried out in open areas where there is direct contact with the ground. The earthing switch will direct electricity, in the event of an increased voltage situation, to the ground.
- Observe technical safety measures using protective insulation (rubber mats , etc.).
In regulatory documents, a special group singles out work carried out in adverse conditions. For example, in boilers, devices, vessels made of metal, where the ability to move the operator and his exit from the enclosed space is limited. In this regard, there is a classification of premises according to the danger of electric shock. Therefore, the requirements for safety conditions are higher than in rooms with special danger.