What protective measures in electric units?
The electrical safety of the operating electric units has to be provided with performance of organizational and technical actions and also application of technical ways and means of protection.
Organizational actions include:
- the admission to work in the operating electric units of the persons which underwent instructing and training in safe methods of work;
- examination of safety rules and instructions according to the post in relation to the performed work with assignment of the corresponding qualification group on electrical safety;
- assignment of the persons responsible for the organization and safety of works;
- execution of the order or order on works;
- drawing up the list of the works performed as the current operation;
- implementation of the admission to work;
- organization of supervision of work;
- registration of breaks in work, transfers into other jobs, completion of work;
- establishment of the rational modes of work.
Technical actions at work in the operating electric units with the dump include:
- disconnection of the electric unit (part of installation) from the power source electric power;
- mechanical locking of drives of the switched-off switching devices;
- removal of safety locks;
- detachment of blocking and the ends of the feeding lines and other actions excluding wrong giving of tension to the place of work;
- check of lack of tension;
- grounding of the disconnected current carrying parts (inclusion of the grounding knives, imposing of the portable grounding devices);
- barrier of the current carrying parts remaining energized which in the course of work it is possible to touch or approach on inadmissible distance;
- installation of signs and posters of safety;
- barrier of the workplace (or current carrying parts) and installation of signs of safety;
- safe arrangement of the working and used mechanisms, devices and devices.
Organizational and technical actions when performing work on the current carrying parts which are energized or near them include:
- performance of work according to the dress not less than 2 persons;
- continuous supervision for performing work;
- application of electroprotective barriers and means;
- isolation of the workplace;
- safe arrangement of the working and used mechanisms and devices.
Ensuring electrical safety with technical ways and means has to be reached by application:
- protective grounding;
- protective shutdown;
- alignments of potential;
- protective shunting;
- small tension;
- divisions of network;
- isolation of current carrying parts (working, additional, double);
- compensations of earth fault currents;
- isolations of the workplace;
- electroprotective equipment (the main and additional).
Technical ways and means of protection apply separately or in their combination so that optimum protection was provided.
The technical ways and means of protection providing electrical safety have to be established taking into account:
- rated voltage;
- sorts and frequencies of current of the electric unit;
- way of power supply (from the fixed network, from the independent power source the electric power);
- neutral mode (average point) of the power source electric power;
- type of execution (stationary, mobile, figurative);
- environmental conditions;
- possibilities of the dump from current carrying parts on which or near which work has to be carried out;
- the nature of possible touch of the person to current circuit elements;
- it is one distance less possibility of approach to the current carrying parts which are energized admissible or hits in the zone of spreading of current;
- types of works (mounting, adjustment, testing, etc.).