Grounding and protective measures for electrical safety. Portable electrical receivers

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Section 1 General Rules

Grounding and protective measures for electrical safety. Portable electrical receivers

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Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

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1.7.147. Portable power receivers in the Rules include power receivers that can be in the hands of a person during their operation (hand-held power tools, portable household electrical appliances, portable radio-electronic equipment, etc.).

1.7.148. Portable AC power receivers should be powered from a mains voltage not exceeding 380/220 V.

Depending on the category of the premises according to the level of danger of electric shock to people (see Chap. 1.1), for protection against indirect contact in circuits supplying portable electrical receivers, automatic power off, protective electrical separation of circuits, extra low voltage, double insulation can be used.

1.7.149. When using automatic power off, metal cases of portable electrical receivers, with the exception of double-insulated electrical receivers, must be connected to the neutral protective conductor in the TN system or grounded in the IT system, for which a special protective (PE) conductor must be provided, located in the same sheath with phase conductors (the third core of a cable or wire - for single-phase and direct current electrical receivers, the fourth or fifth core - for three-phase current electrical receivers), attached to the body of the electrical receiver and to the protective contact of the plug connector. The PE conductor must be copper, flexible, its cross section must be equal to the cross section of the phase conductors. The use of a zero working (N) conductor for this purpose, including one located in a common sheath with phase conductors, is not allowed.

1.7.150. It is allowed to use stationary and separate portable protective conductors and potential equalization conductors for portable electrical receivers of testing laboratories and experimental installations, the movement of which is not provided for during their operation. In this case, stationary conductors must meet the requirements of 1.7.121-1.7.130, and portable conductors must be copper, flexible and have a cross section not less than that of phase conductors. When laying such conductors not as part of a cable common with phase conductors, their cross-sections must be at least those specified in 1.7.127.

1.7.151. For additional protection against direct contact and indirect contact, socket outlets with a rated current of not more than 20 A for outdoor installation, as well as indoor installation, but which can be connected to portable electrical receivers used outside buildings or in rooms with increased danger and especially dangerous, must be protected by residual current devices with a rated residual current of not more than 30 mA. It is allowed to use hand-held power tools equipped with RCD plugs.

When using protective electrical separation of circuits in cramped rooms with conductive floors, walls and ceilings, as well as in the presence of requirements in the relevant chapters of the PUE in other rooms with special danger, each outlet must be powered by an individual isolating transformer or from its separate winding.

When using extra-low voltage, portable electrical receivers with voltage up to 50 V must be supplied from a safety isolating transformer.

1.7.152. To connect portable power receivers to the mains, plug connectors that comply with the requirements of 1.7.146 should be used.

In plug connectors of portable electrical receivers, extension wires and cables, the conductor on the side of the power source must be connected to the socket, and on the side of the electrical receiver - to the plug.

1.7.153. RCD protection of socket circuits is recommended to be placed in distribution (group, apartment) shields. It is allowed to use RCD sockets.

1.7.154. Protective conductors of portable wires and cables must be marked with yellow-green stripes.

See other articles Section Rules for the installation of electrical installations (PUE).

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