Chương III Thông tư 31/2014/TT-BCT: Nối đất kết cấu kim loại trong và liền kề hành lang bảo vệ an toàn đường dây dẫn điện trên không đối với điện áp từ 220 kv trở lên phòng tránh điện cảm ứng

Chapter III

GROUND WIRING OF METAL STRUCTURE INSIDE AND NEAR PROTECTION BARRIERS OF OVERHEAD TRANSMISSION LINES AT 220 KV OR HIGHER FOR PRECLUSION OF ELECTRICAL INDUCTION

Article 10. Ground wiring range

1. At the voltage of 220 kV: 25 meters from the edge of the outer or lowest line inside and near the protection barriers.

2. At the voltage of 500 kV: 60 meters from the edge of the outer or lowest line inside and near the protection barriers.

Article 11. Targets for ground wiring

1. Residences and buildings with metal roofs: Roofs shall be connected to the ground. Ground wiring is not required for metal parts under the roof.

2. Residences and buildings with non-metal roof: All insulated metal parts such as partitions, walls, girders, beams, rafters and window frames shall be connected to the ground.

3. All metal structures outside residences and buildings such as iron frames, aluminum panels, television antenna, clothes lines.

Article 12. Ground wiring technique

1. Ground rod is made of round steel bar in diameter of at least 16 mm or square steel bar with equivalent gauge or steel angle with smallest measurements at 40x40x4 mm. The buried part of the rod must be at least 0.8 meter long (in vertical direction). The other end of the rod protrudes from the ground (less than 0.15 meter high). The location of the ground rod must not cause inconveniences to occupants in houses and buildings. Insulation coating must not be applied on the ground rod’s surface. Ground rods prone to corrosion must be copper bonded or zinc plated.

2. Earth wire may be made of round steel wire in smallest diameter of 6 mm or flat steel wire with least measurements at 24x4 mm or multi-strand soft copper wire with least gauge of 16 mm². If earth wire is made of steel, it must be zinc plated or applied with anti-rust paint.

3. Earth wire shall be bolted or welded to the exposed part of the ground rod and the metal structure that requires ground wiring.

4. If ground wiring is readily in use, extra ground rod shall not be required though earth wire must be bolted or welded.

Article 13. Responsibilities for ground wiring and earthing system management

1. Responsibilities for ground wiring

a) Main investor of the high-voltage power grid shall bear all expenses and responsibilities for installing the earthing system for residences and buildings that come into existence prior to the construction of the high-voltage power grid.

b) Legitimate users of residences and buildings built after the high-voltage power grid shall install the earthing system or give requests and incur all expenses for the organization managing and operating the high-voltage power grid to set up the earthing system.

2. Management of earthing system

Legitimate owners and users of residences and buildings with metal structures connected to the ground must manage the earthing system. Upon the detection of the earthing system's damage or anomalies, the organization managing and operating the high-voltage power grid must be informed promptly for joint actions.