GB 51120-2015 English PDFUS$1159.00 · In stock
Delivery: <= 8 days. True-PDF full-copy in English will be manually translated and delivered via email. GB 51120-2015: Acceptance code for lightning protection and earthing engineering of telecommunication bureaus (stations) Status: Valid
Basic dataStandard ID: GB 51120-2015 (GB51120-2015)Description (Translated English): Acceptance code for lightning protection and earthing engineering of telecommunication bureaus (stations) Sector / Industry: National Standard Word Count Estimation: 55,516 Date of Issue: 2015-08-27 Date of Implementation: 2016-05-01 Quoted Standard: GB 50689 Regulation (derived from): Ministry of Housing and Urban?Rural Development Announcement No.888 Issuing agency(ies): Ministry of Housing and Urban-Rural Development of the People's Republic of China; General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Summary: This standard is applicable to acceptance of lightning protection and earthing works of new bureau, extension and alteration bureau (station). GB 51120-2015: Acceptance code for lightning protection and earthing engineering of telecommunication bureaus (stations)---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order. 1 General 1.0.1 In order to strengthen the quality supervision and management of lightning protection and grounding projects of communication bureaus (stations), unify the requirements for project construction quality and acceptance, and ensure the project quality and safe operation of lightning protection and grounding devices, this specification is formulated. 1.0.2 This specification is applicable to the acceptance of lightning protection and grounding works of new construction, expansion and reconstruction of communication bureaus (stations). 1.0.3 The acceptance of lightning protection and grounding works of communication bureaus (stations) shall not only comply with this specification, but also comply with the relevant current national standards. 2 terms 2.0.1 Common earthing Different grounding methods of various communication equipment in communication bureaus (stations), including working grounding, protective grounding, shielding grounding, anti-static grounding, information equipment logic grounding, etc. The protective grounding of the lightning arrester is connected together, and the grounding method of the basic grounding body of the building and the peripheral grounding system are used together with the lightning protection grounding of the building. 2.0.2 air-termination system A device used to receive direct lightning discharges to protect the protected object from lightning strikes. Including lightning rods, lightning belts (wires), lightning nets, and metal roofs and metal components used for lightning. 2.0.3 down-conductor system The metal conductor connecting the air-termination device to the grounding device. 2.0.4 direct stroke protection system The sum of air receptors and down conductors. 2.0.5 Earthing electrode A conductor or a group of conductors that are in close contact with the soil (earth) and provide an electrical connection to the soil (earth) for the purpose of connection to the earth. 2.0.6 Earth grid A group of grounding bodies consisting of interconnected bare conductors buried in the ground to provide a common ground for electrical equipment or metallic structures. 2.0.7 earth connection The conductor connected between the ground grid and the general ground busbar. 2.0.8 earth-termination system The sum of the ground lead-in and the ground grid. 2.0.9 Equipotential bonding equipotentiai bonding Connect separate devices or multiple conductive objects with conductors or lightning arresters to reduce the potential difference between them caused by lightning current. 2.0.10 Earth conductor The grounding wire is the cable used in the equipotential connection, which refers to the equipment of the communication bureau (station), the elevator track, the crane, the metal floor, the metal door frame, the metal pipe, the metal cable tray, the railing on the outer wall, etc. The conductive object is reliably connected to the grounding bus bar or the cable between the grounding pooling lines. 2.0.11 earth terminal A collection of conductors for various grounding wires. 2.0.12 Grounding collection line mail earth conductor The grounding collection line refers to the strip-shaped copper bar or flat steel as the grounding conductor. It is usually used as the main line of the grounding system in the communication bureau (station). According to the laying method, it can be classified into horizontal grounding collection line, vertical grounding collection line, ring Grounding pooling wire or strip grounding pooling wire. 2.0.13 earthing system earthing system All electrical connections and devices included in the grounding of systems, devices and equipment, including grounding bodies buried in the ground, grounding wires, cable shields connected to grounding bodies, and equipment shells or exposed metal parts connected to grounding bodies, Complex systems including building reinforcement and frames. 2.0.14 rolling sphere method A simplified analysis method for the application of electrical geometry theory in lightning protection analysis of buildings. The rolling ball method involves rolling an imaginary ball with a specified radius along the surface of the protected object. The ball is supported by lightning rods, lightning conductors, fences and other grounded metal objects, and rolls up and down for calculating the lightning protection range. A piece of equipment is protected if it is under the protective surface formed by the rolling of the ball, and equipment that touches the ball or penetrates its surface is not protected. 2.0.15 soil resistivity earth resistivity A parameter that characterizes the conductivity of the soil, its value is equal to the resistance between the two opposite sides of the soil per unit cube, and the unit is Ω·m. 2.0.16 power frequency earth resistance When the power frequency current flows through the grounding device, the resistance between the grounding body and the remote earth. Its value is equal to the ratio of the voltage of the grounding device relative to the remote earth to the current flowing into the ground through the grounding body. 2.0.17 surge protective device, SPD Devices for protecting communication systems under lightning overvoltage, operating overvoltage, etc. A device for protecting equipment by suppressing transient overvoltages and bypassing surge currents, which contains at least one non-linear element. 3 Basic Regulations3.0.1 The grounding system of the communication bureau (station) must adopt the joint grounding method. 3.0.2 The power supply mode of the communication bureau (station) shall comply with the relevant provisions of the current national standard GB 50689 "Code for Design of Lightning Protection and Grounding Engineering of Communication Bureau (Station)". 3.0.3 The main equipment and materials used in the lightning protection and grounding works of communication bureaus (stations) shall meet the following requirements. 1.The type and specification of equipment and materials shall meet the engineering design requirements. When alternative materials need to be used, they shall be approved by the construction unit and the design unit, and shall be used after going through the modification procedures; 2 The equipment and materials should be inspected when they enter the site, and should be used after passing the inspection; 3 Outdoor steel materials and fasteners should be hot-dip galvanized products or stainless steel products; 4 The galvanized layer of galvanized products should be completely covered and free from rust spots on the surface. 3.0.4 When bolt connection is used in the lightning protection and grounding system, the contact surface shall be ground and anti-loosening parts shall be installed. 3.0.5 When the lightning protection and grounding system is connected or fixed by welding, paint, paint, enamel and other non-conductive coatings should be removed, the welding should be firm, the weld seam should be full and smooth, and the welded part should be free of solder joints and pores. 3.0.6 When lap welding is used to connect steel materials, the lap length and welding method shall meet the following requirements. 1 For the lap joint between flat steel and flat steel, the overlapping length shall not be less than twice the width of the flat steel, and shall not be less than three-side welding; 2.For lap joints between round steel and round steel, the overlapping length shall not be less than 10 times the diameter of the round steel, and welding shall be performed on both sides; 3 For lap joints between round steel and flat steel, the lap length shall not be less than 10 times the diameter of the round steel, and welding shall be performed on both sides; 4 When flat steel and angle steel are welded, the wide surface of the flat steel should be close to the outer surface of the angle steel, and welding should be done on both sides; 5 When the flat steel is welded to the steel pipe, in addition to welding on both sides of the contact part, arc-shaped clips bent from the flat steel or directly bent into an arc from the flat steel itself are welded to the steel pipe. More than 3/4 of the surface of the steel pipe is in contact with the flat steel. 3.0.7 In the lightning protection and grounding system, anti-corrosion treatment should be done at the damaged parts and welding parts of the metal surface coating. Anti-corrosion treatment should adopt the method of painting asphalt or anti-rust paint and other anti-corrosion coatings. Before coating the anti-corrosion coating, the dust, oil, scale, rust layer, pollutants, loose old paint film and solder joints on the metal surface should be removed. The anti-corrosion coating should be applied uniformly, with good adhesion, no missing coating, no wrinkled skin, no dripping, and no air bubbles. 3.0.8 When exothermic welding is used in the lightning protection and grounding system, the welded joints shall completely cover the connecting parts of the connected conductors, and the metal at the connecting parts shall be completely melted and the connection shall be firm.4 Grounding device4.1 Grounding body and grounding grid 4.1.1 The location, length, spacing of the grounding body and the installation method of the grounding grid shall meet the engineering design requirements. 4.1.2 The grounding grids of multiple buildings and iron towers in the communication bureau (station) should use horizontal grounding bodies for multi-point connection. 4.1.3 When the power transformer is installed in the machine room, the transformer should be grounded with a joint grounding grid. When the power transformer is installed outside the machine room and the edge of the transformer grounding grid is less than 30m from the edge of the joint grounding grid, a horizontal grounding body should be used to weld the transformer grounding grid and the joint grounding grid. 4.1.4 The grounding body should avoid the sewage outlet and the section with strong soil corrosion. 4.1.5 Grounding body pits and ditches should be excavated outside the water point of the building, and the distance from the building foundation should be greater than 1m. 4.1.6 When the grounding body crosses or parallels with buried power cables and communication optical (electrical) cables, a safe distance should be kept between the grounding body and the cables according to the design requirements. When the grounding grid passes through walls, foundations or directly buried cables, it shall be reinforced or protected according to the design requirements. 4.1.7 The buried depth of the upper end of the grounding body should not be less than 0.7m, and it should be buried below the frozen soil layer in cold regions. When buried in special areas such as permafrost, the buried depth should meet the design requirements. In rocky mountains with thin soil or gravel and rocky areas, the burial depth of the grounding body can be determined according to specific conditions, and the grounding body should not be exposed to the surface. 4.1.8 The horizontal grounding body should be dug and buried, and the laying should be straight; the steel vertical grounding body should be driven directly into the trench, and the distance should not be less than twice its length and should be evenly arranged; the vertical grounding body of other materials should be dug. buried. The horizontal grounding body and the vertical grounding body shall be connected by welding. 4.1.9 The ring-shaped grounding body should be connected to the foundation ground network of the building at multiple points, and should be reliably electrically connected to various metal piping systems such as upper and lower water pipes and other metal conductors entering the building. 4.1.10 It is not suitable to lay other cables in the grounding trench. 4.1.11 The backfill soil of ground pits and ditches should not be highly corrosive, should use low-resistivity soil, and should not contain stones or construction waste. 4.1.12 When the drag-reducing agent is used in areas with high soil resistivity, the drag-reducing agent should be evenly wrapped around the grounding body. 4.1.13 The grounding resistance test point of the grounding network shall be clearly marked, and the mark shall be a black "¤" symbol on a white background. 4.1.14 The grounding resistance value of the grounding grid or the area of the grounding grid should meet the engineering design requirements. The grounding resistance shall be tested according to the test method specified in Appendix A of this specification. 4.2 Ground lead-in 4.2.1 The quantity and location of the grounding lead-in wires should meet the design requirements. 4.2.2 The grounding lead-in line should not be laid in the same ditch as the heating pipe, and should avoid sewage pipes and ditches when buried. 4.2.3 The connection point between the grounding lead-in wire and the ground grid should avoid the main lightning current discharge points such as the down conductor and the base of the iron tower. 4.2.4 The connection between the grounding lead-in wire and the grounding body shall be by welding. 4.2.5 The excavated part of the grounding lead-in wire, the intersection with the road and other places that may cause mechanical damage to the grounding lead-in wire should be protected by galvanized steel pipe or galvanized angle steel and should be treated with anticorrosion.6 Equipotential bonding6.1 Ground bar and ground pooling line 6.1.1 The material specifications and installation positions of the grounding bar, the horizontal grounding collection line of each layer, and the vertical grounding collection line shall meet the engineering design requirements. Grounding bars, horizontal grounding collection lines, vertical grounding collection lines, ring grounding collection lines, and building reinforcements should be reliably connected according to engineering design requirements. 6.1.2 There should be no burrs, obvious scars, and residual welding slag on the surface of the grounding bar and the grounding collection line, and the installation should be flat, correct, firm and reliable. 6.1.3 A permanent mark shall be set on the grounding bar, and the purpose of the grounding bar shall be marked. 6.1.4 The outdoor ground bar of the base station should be directly connected to the ground grid through the ground wire, and should not be connected to the tower body or the outdoor cable rack, and should not be connected to the indoor grounding device. 6.2 Grounding of installations 6.2.1 The rack of communication equipment shall be connected to the grounding bus bar separately with the grounding wire according to the design requirements, and the digital distribution frame may adopt the multiple connection method. 6.2.2 When using the grounding bolt on the rack to ground the shell of the communication equipment, the spiky washer should be used, and the spiky washer should be located between the shell of the equipment and the grounding terminal. 6.2.3 The outer conductor of the intra-office RF coaxial cable and the two ends of the shielding layer of the shielded cable shall maintain electrical communication with the outer surface of the metal casing of the connected equipment or machine panel. 6.2.4 Elevator rails, pipes, brackets, metal support components, metal shafts, metal ventilation pipes, metal doors and windows, metal channels, cable racks and other large-sized internal conductive objects in the communication bureau (station) shall be grounded nearby according to the design requirements, the connection method between the metal member and the ground wire should be welded or bolted. The metal shafts, metal channels, and cable racks of each section shall be electrically connected, and the indoor cable racks shall not be connected with the outdoor cable racks. When it is difficult to weld the ground wire and the metal pipe, it can be connected with a clamp, but it should be electrically connected. 6.2.5 The metal shells, masts, poles and outdoor cable racks of various equipment on the top of the building shall be reliably welded to the roof lightning protection belt (net) through flat steel, and anti-corrosion measures shall be taken. 6.3 Ground wire 6.3.1 A permanent mark shall be set near the terminal on the grounding wire, and the position of the opposite end shall be marked. 6.3.2 It is strictly forbidden to install switches or fuses in the grounding wire. 6.3.3 The laying of the grounding wires should be short, straight and neat, and the excess cables should be cut off and not coiled; the binding spacing of the grounding wires on the wire slot or cable rack should be even and reasonable, the binding buckles should be neat, and the binding buckles should not be exposed. 6.3.4 When the grounding wire is connected to the equipment or the grounding bar, a copper terminal must be installed, and it should be pressed (welded) firmly. 6.3.5 The size of the terminal should match the diameter of the grounding wire; the flat contact part of the terminal should be flat, free from rust and oxidation; after the terminal is crimped (welded), it should be covered with a yellow-green two-color thermoplastic sleeve, It can also be wrapped with yellow and green double-color insulating plastic tape. 6.3.6 Galvanized bolts should be used for connection between the terminal and the grounding bar. One bolt should be crimped with one grounding wire. The connection should be reliable and beautiful, and the connection of the grounding bar should be hot tinned.7 Grounding and Protection of Cables7.3.3 When the cables are laid on the cable tray, the binding spacing should be even and reasonable, the binding buckles should be neat and tight, and the binding buckle plows should not be exposed. 7.3.4 The places where cables pass through walls, floors and floors should be protected by sleeves. When metal pipes are used, both ends of the metal pipes should be grounded nearby. The installation of the bushing shall comply with the provisions of Article 4.2.6 of this code. 7.3.5 The grounding points of metal sheaths and metal components of weak current signal cables should not be established or introduced near the pillars used as lightning downconductors. 7.3.6 Unshielded weak current signal cables should not be laid on the outer wall. When it needs to be laid on the outer wall, all the cables should be inserted into the shielded metal tube according to the design requirements, and both ends of the metal tube should be grounded nearby. 7.3.7 When weak current signal cables are laid on metal structures such as communication towers, poles or elevated frames, the lines should be laid with shielded cables or metal protection tubes according to the design requirements, and the shielding layer or metal protection tubes of the cables should be grounded at both ends. 7.3.8 The layout of monitoring cables shall comply with the following regulations. 1.It should be far away from structures that may be directly struck by lightning, such as iron towers, and should not be wired along the corners of buildings. 2 It should not be close to the column or beam of the building. When it needs to be close to the column or beam of the building, the length of the wiring along the column or beam should be reduced. 3.Shielded cables should be used. Unshielded cables should pass through metal pipes or be placed in shielding slots according to the desi......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB 51120-2015_English be delivered?Answer: Upon your order, we will start to translate GB 51120-2015_English as soon as possible, and keep you informed of the progress. The lead time is typically 5 ~ 8 working days. The lengthier the document the longer the lead time.Question 2: Can I share the purchased PDF of GB 51120-2015_English with my colleagues?Answer: Yes. The purchased PDF of GB 51120-2015_English will be deemed to be sold to your employer/organization who actually pays for it, including your colleagues and your employer's intranet.Question 3: Does the price include tax/VAT?Answer: Yes. 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