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Earthing (grounding) system according to IEC, BS-EN and IEEE standards

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작성자 관리자 댓글 0건 조회 493회 작성일 22-10-17 09:32

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Earthing (grounding) system according to IEC, BS-EN and IEEE standards

Step 1
Good earthing (grounding) system according to IEC/BS EN 62305-3:2011 standard

E.5.4 Earth-termination system
E.5.4.1 General
(…) The LPS designer and the LPS installer should select suitable types of earth electrodes and should locate them at safe distances from entrances and exits of a structure and from the external conductive parts in the soil, such as cables, metal ducts, etc. Hence the LPS designer and the LPS installer should make special provisions for protection against dangerous step voltages in the vicinity of the earth-termination networks if they are installed in areas accessible to the public (see Clause 8).
The recommended value of the overall earth resistance of 10 Ω is fairly conservative in the case of structures in which direct equipotential bonding is applied. The resistance value should be as low as possible in every case but especially in the case of structures endangered by explosive material. Still the most important measure is equipotential bonding.

E.5.4.2.2 Type B arrangement
(…) The type B earth-termination system is preferred for meshed air-termination systems and for LPS with several down-conductors.
This type of arrangement comprises either a ring earth electrode external to the structure, in contact with the soil for at least 80% of its total length, or a foundation earth electrode.

E.5.4.3.2 Foundation earth electrodes
(…) A further problem arises from electrochemical corrosion due to galvanic currents. Steel in concrete has approximately the same galvanic potential in the electrochemical series as copper in soil. Therefore, when steel in concrete is connected to steel in soil, a driving galvanic voltage of approximately 1 V causes a corrosion current to flow through the soil and the wet concrete and dissolve steel in soil.
Earth electrodes in soil should use copper, copper coated steel or stainless steel conductors where these are connected to steel in concrete.