GBJ 79-1985 Industrial enterprise communication grounding design specification
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Engineering Construction Standard Full-text Information System
National Standard of the People's Republic of China
Design Specification for Communication Grounding of Industrial Enterprises
GBJ79—85
1985Beijing
Engineering Construction Standard Full-text Information System
W Engineering Construction Standard Full-text Information System
National Standard of the People's Republic of China
Design Specification for Communication Grounding of Industrial Enterprises
GBJ79—85
Editor Department:
Approval Department ：
Ministry of Posts and Telecommunications of the People's Republic of China
State Planning Commission of the People's Republic of China January 1, 1986
Effective Date:
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Notice on the Release of
"Design Specification for Communication Grounding of Industrial Enterprises" Standard Planning [1985] No. 1110
According to the requirements of the former State Construction Commission, the "Design Specification for Communication Grounding of Industrial Enterprises" compiled by the Ministry of Posts and Telecommunications has been reviewed by relevant departments. The "Design Specification for Communication Grounding of Industrial Enterprises" GBJ79-85 is now approved as a national standard and will be implemented from January 1, 1986. This specification is managed by the Ministry of Posts and Telecommunications, and its specific interpretation and other work are the responsibility of the Beijing Design Institute of the Ministry of Posts and Telecommunications, and its publication and distribution are organized by the Basic Construction Standard and Quota Research Institute of our Commission. State Planning Commission
July 22, 1985
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Preparation Instructions
"Industrial Enterprise Communication Grounding Design Specification" is compiled by our department in accordance with the requirements of the former National Capital Construction Committee, and the specific compilation work is undertaken by the Beijing Design Institute of the Ministry of Posts and Telecommunications. During the compilation of this specification, a relatively extensive investigation and research, on-site experiments and tests were carried out, and the experience of various aspects was summarized. The opinions of relevant units across the country were widely verified, and finally the draft was reviewed and finalized in conjunction with relevant departments. This specification is divided into four chapters and three appendices. The main contents include general principles, general provisions, grounding resistance and grounding devices.
During the implementation of this specification, please pay attention to accumulating information and summarizing experience. If you find that there is a need for modification or supplementation, please send your opinions and relevant information to the Beijing Design Institute of the Ministry of Posts and Telecommunications for reference in future revisions. Ministry of Posts and Telecommunications
June 1985
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Chapter 1 General Provisions
Chapter 2
General Provisions
Section 1 Grounding of Telecommunication Stations
Section 2 Grounding of Cable Lines
Section 3 Grounding Strategies for Pole Lines, Open Wires and Terminal Equipment Chapter 3 Grounding Resistance
Section 1 Grounding Resistance of Telecommunication Stations
Section 2 Grounding Resistance of Cable Lines.
Section 3
Pole Lines, Open Wires and Terminal Equipment Grounding resistance. Chapter 4
Appendix 1
Appendix 3
Appendix 3
Grounding device:
Term explanation
Utilization coefficient of grounding device
Terms used in this specification
Additional explanation
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Chapter 1 General
Article 1.0.1 The design of communication grounding of industrial enterprises should prevent external voltage from endangering personal safety and damaging equipment, suppress electrical interference, and ensure the normal operation of communication equipment.
Article 1.0.2 This specification applies to the communication grounding design of telecommunication stations, cable broadcasting stations and off-site lines of general industrial enterprises. Article 1.0.3 In addition to being implemented in accordance with this specification, the design of communication grounding of industrial enterprises should also comply with the provisions of the current "Industrial Enterprise Communication Design Specification" of the state. Article 1.0.4 The communication grounding with special requirements in power plants, substations, mines and explosion-proof environments, as well as the design of special communication grounding set up according to lightning protection, strong current protection, corrosion protection, and protection against the influence of electrified railways, shall comply with the relevant provisions in the corresponding specifications. Engineering Construction Standard Full Text Information System
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Chapter II General Provisions
Section I Grounding of Telecommunication Stations
Article 2.1.1 The DC power supply of the telecommunication station, the lightning arrester of the open wire or cable entering the station, the rack and casing of the telecommunication equipment, the metal sheath or shielding layer of the incoming communication cable, etc. shall be grounded and connected to the communication grounding device shared by the entire station. Article 2.1.2 The normally non-charged metal parts of the power supply equipment such as the AC distribution panel (panel) and rectifier panel (panel) of the telecommunication station shall adopt zero protection when they are not in the same rack or cabinet with the communication equipment.
When the normally non-conductive metal parts of the DC distribution panel (panel) are electrically connected to the normally non-conductive metal parts of the AC distribution panel (panel) and the rectifier panel (panel) by the reinforcement device, they should also be protected by zero connection. When they are not connected, they should be protected by grounding and connected to the communication grounding device.
When the normally non-conductive metal parts of the power rectifier panel in the rack and cabinet of the AC/DC dual-purpose communication equipment are not insulated from the rack and cabinet, they should be protected by grounding and connected to the communication grounding device.
Article 2.1.3 The communication grounding of the telecommunication station should not be interconnected with the industrial frequency AC grounding. When the telecommunication station has a dedicated AC power supply transformer or is located in a building with a dedicated AC power supply transformer, its communication grounding device can be used together with the grounding device of the neutral point of the dedicated AC transformer. At this time, various communication equipment that need to be grounded should be connected to the neutral point of the transformer or the main grounding bar using a dedicated zero connection trunk line, and the neutral line with three-phase unbalanced current should not be used to connect to the neutral point of the transformer.
Article 2.1.4 The communication grounding of the telecommunication station should not be interconnected with the lightning protection grounding of the building. When the lightning protection grounding of the building uses the metal components of the building structure as the discharge conductor, the communication grounding should be connected with the lightning protection grounding of the building and the grounding of the power frequency AC power supply system at the main grounding bar. Article 2.1.5 When it is required to strictly limit the interference of power frequency AC to communication equipment, and it is not easy to insulate the communication equipment from various metal components in the station, the building where the telecommunication station is located should adopt a three-phase five-wire power supply system, and the various groundings described in Articles 2.1.2 to 2.1.4 should be connected to the fifth wire, and no separate communication grounding device is required. Article 2.1.6 The grounding of wired broadcasting equipment can use the communication grounding device. However, if the wired broadcasting equipment has an antenna device and may be struck by lightning, the antenna lightning protection grounding should be set separately.
Article 2.1.7 The DC power supply of the factory (mine) telephone exchange shall be positively grounded, except for special requirements of the equipment.
Article 2.1.8 The grounding device of the factory (mine) telephone exchange that uses the earth as a signal loop shall be equipped with two sets of grounding bodies with similar grounding resistance values, which shall be introduced into the room by different grounding lead-in wires.
Section 2 Grounding of Cable Lines
Article 2.2.1 For underground cables laid in open areas, when the annual number of thunderstorm days in the area is greater than 20 days and the soil resistivity is greater than 100 ohm-meters, the metal sheath or shielding layer of the cable shall be grounded every 2 kilometers or so. When the soil resistivity is less than 500 ohm-meters, the natural grounding of the oil-hemp asphalt armored cable can replace the above grounding. Article 2.2.2 When anti-corrosion grounding and lightning protection grounding are set at the same location for underground cable lines, the anode anti-corrosion grounding device should be used together with the lightning protection grounding device; the cathode anti-corrosion grounding device should be set separately from the lightning protection grounding device. Article 2.2.3 The lightning arrester of the cable junction box should be grounded. The metal sheath of the overhead cable and its steel strands should be grounded every 250 meters or so; in open areas, they should be grounded every 1 meter or so. At the cable junction box, the metal sheath of the overhead cable and its steel strands should share the grounding device with the cable junction box. Section 3 Grounding of Pole Lines, Open Wires and Terminal Equipment Article 2.3.1 The following poles of various types of overhead communication lines located in open areas shall be equipped with lightning rods and their grounding:
1. Terminal poles, lead-in poles and five poles adjacent to them; Engineering Construction Standard Full Text Information System
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2. Branch poles, test poles, flying line crossing poles, poles over 12 meters high, poles located at high places, and corner poles with a corner depth greater than 1 meter; 3. Poles equipped with dischargers, lightning arresters, and discharge gaps; 4. Poles on both sides when crossing power lines of 1 kV and above; 5. In areas with frequent lightning activities, every 5 to 10 poles; 6. Poles that have been struck by lightning.
Article 2.3.2 In accordance with Article 2.3.Article 1 The second, fourth, fifth, sixth and first paragraphs of the five poles adjacent to the terminal pole and the lead-in pole require the installation of lightning rods on reinforced concrete poles, and the lightning rods should be connected to the steel bars at the top of the poles as lightning rod grounding. Article 2.3.3 The lightning rods of poles equipped with dischargers, lightning arresters and discharge gaps can use their grounding devices as lightning rod grounding. The poles with guy wires can use the guy wire devices as lightning rod grounding.
Article 2.3.4 When crossing and crossing with 1 kV and above power lines, the grounding wires of the lightning rods of wooden poles on both sides and wooden poles parallel to 110 kV and above power lines that are affected by danger should leave a 5 cm gap at 2 meters from the ground. Article 2.3.5 Except for Articles 2.3.2 to 2.3.4, in other cases, the lightning rod grounding wires of poles can be laid along the poles to the bottom as grounding. Article 2.3.6 Overhead wires in open areas should be equipped with lightning arresters and grounding poles where they enter telecommunications stations or intermediate cables, and graded protective grounding should be set up within a range of about 2 kilometers from the pole. The layout of graded protective grounding shall comply with the provisions of Table 2.3.6: Layout of graded protective grounding
Distance from terminal pole
(m)
Graded protection
At terminal pole
0.3mm
Gap spark gap
150~200
3mm
Discharge gap
500~600
7mm
Discharge gap
1000~1200
10mm
Discharge gap
1800~2200
15mm
Discharge gap
Note: In areas where lightning activity is not frequent, the 10mm and 15mm discharge gaps can be cancelled. Article 2.3.7 Overhead ground wires can be installed near the lead-in poles or the terminal poles of the incoming and intervening cables of telecommunication stations located in open areas, as well as areas with repeated lightning strikes. The overhead ground wires should be grounded, and the grounding interval should not be greater than 100 meters. Overhead ground wires should not be grounded at lead-in poles, terminal poles, and poles equipped with graded protective discharge gaps. Article 2.3.8 User terminal equipment connected to cables or open wires in open areas should be equipped with protective devices, and their lightning arresters should be grounded. Engineering Construction Standard Full Text Information System
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Chapter 3
Grounding Resistance
Section 1 Grounding Resistance of Telecommunication Stations
Article 3.1.1 The resistance value of the grounding device of communication equipment such as factory (mine) area telephone exchanges, carriers, dispatch telephone switchboards, conference telephone tandems or terminals, wired broadcast amplifiers, and production amplifiers that do not use the earth as a signal loop shall comply with the following provisions:
1. The grounding resistance value of DC power supply communication equipment shall not be greater than 15 ohms. 2. The grounding resistance value of AC power supply or AC/DC dual-purpose communication equipment shall not be greater than 10 ohms when the AC single-phase load of the equipment is less than or equal to 0.5 kVA; when it is greater than 0.5 kVA, it shall not be greater than 4 ohms.
Article 3.1.2 The grounding resistance value of the two sets of grounding bodies of the factory (mine) area telephone exchange that uses the earth as a signal loop after being connected in parallel shall not be greater than the provisions of Table 3.1.2. Table 3.1.2 of the grounding resistance of telephone exchanges using the earth as signal loops
Switch capacity (ports)
Grounding resistance value (ohm)
≤600
《1000
≤2000
≤4000
Article 3.1.3
When the grounding of the telecommunication station complies with the provisions of Article 2.1.3, the resistance value of the grounding device shall comply with the provisions of the grounding resistance value of the telecommunication station and the provisions of the neutral point grounding resistance value of the AC power supply transformer in the national "Grounding Design Code for Industrial and Civil Power Installations".
The grounding resistance value of the total grounding bar that complies with the provisions of Article 2.1.4 Article 3.1.4
shall not be greater than 1 ohm.
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Section 2
Grounding Resistance of Cable Lines
Article 3.2.1 The grounding resistance value of the metal sheath or shielding layer of underground cables for lightning protection grounding shall comply with the following provisions:
1. When p<100
2. When p>100
(3.2.1-1)
(3.2.1-2)
Where: p——soil resistivity (ohm-meter); R——grounding resistance value (ohm);
S——grounding interval (kilometer).
Article 3.2.2 The grounding resistance value of the metal sheath of overhead cables and their steel strands shall not be greater than that specified in Table 3.2.2.
Grounding resistance of overhead cable metal sheath and its steel strands Soil resistivity (ohm-meter)
Grounding resistance value (ohm)
100<≤300
300<500
Article 3.2.3 When cathodic protection is used for underground cables, the grounding resistance value of the cathodic protection equipment shall be determined based on the required discharge flow of the cable and the soil resistivity of the location of the cathodic protection equipment, taking into account the grounding resistance value and the power consumption value of the cathodic protection equipment.
Article 3.2.4 When anode protection is used for underground cables, the anode grounding resistance value shall be determined based on the type and length of the cable to be protected. Section 3 Grounding resistance of poles, open wires and terminal equipment Article 3.3.1 The grounding resistance values of various groundings of poles and open wires shall not be greater than those specified in Table 3.3.1.
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Article 2 The grounding resistance value of the two sets of grounding bodies of the factory (mine) area telephone exchange that uses the earth as the signal circuit should not be greater than the provisions of Table 3.1.2. Table 3.1.2 of the grounding resistance of the telephone exchange that uses the earth as the signal circuit
Switch capacity (ports)
Grounding resistance value (ohm)
≤600
《1000Www.bzxZ.net
≤2000
≤4000
Article 3.1.3
When the grounding of the telecommunication station complies with the provisions of Article 2.1.3, the resistance value of the grounding device should also comply with the provisions of the telecommunication station grounding resistance value and the national "Grounding Design Code for Industrial and Civil Power Installations" on the neutral point grounding resistance value of the AC power supply transformer.
The grounding resistance value of the total grounding bar that complies with the provisions of Article 2.1.4 Article 3.1.4
should not be greater than 1 ohm.
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Section 2
Grounding Resistance of Cable Lines
Article 3.2.1 The grounding resistance value of the metal sheath or shielding layer of underground cables for lightning protection grounding shall comply with the following provisions:
1. When p<100
2. When p>100
(3.2.1-1)
(3.2.1-2)
Where: p——soil resistivity (ohm-meter); R——grounding resistance value (ohm);
S——grounding interval (kilometer).
Article 3.2.2 The grounding resistance value of the metal sheath of overhead cables and their steel strands shall not be greater than that specified in Table 3.2.2.
Grounding resistance of overhead cable metal sheath and its steel strands Soil resistivity (ohm-meter)
Grounding resistance value (ohm)
100<≤300
300<500
Article 3.2.3 When cathodic protection is used for underground cables, the grounding resistance value of the cathodic protection equipment shall be determined based on the required discharge flow of the cable and the soil resistivity of the location of the cathodic protection equipment, taking into account the grounding resistance value and the power consumption value of the cathodic protection equipment.
Article 3.2.4 When anode protection is used for underground cables, the anode grounding resistance value shall be determined based on the type and length of the cable to be protected. Section 3 Grounding resistance of poles, open wires and terminal equipment Article 3.3.1 The grounding resistance values of various groundings of poles and open wires shall not be greater than those specified in Table 3.3.1.
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Article 2 The grounding resistance value of the two sets of grounding bodies of the factory (mine) area telephone exchange that uses the earth as the signal circuit should not be greater than the provisions of Table 3.1.2. Table 3.1.2 of the grounding resistance of the telephone exchange that uses the earth as the signal circuit
Switch capacity (ports)
Grounding resistance value (ohm)
≤600
《1000
≤2000
≤4000
Article 3.1.3
When the grounding of the telecommunication station complies with the provisions of Article 2.1.3, the resistance value of the grounding device should also comply with the provisions of the telecommunication station grounding resistance value and the national "Grounding Design Code for Industrial and Civil Power Installations" on the neutral point grounding resistance value of the AC power supply transformer.
The grounding resistance value of the total grounding bar that complies with the provisions of Article 2.1.4 Article 3.1.4
should not be greater than 1 ohm.
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Section 2
Grounding Resistance of Cable Lines
Article 3.2.1 The grounding resistance value of the metal sheath or shielding layer of underground cables for lightning protection grounding shall comply with the following provisions:
1. When p<100
2. When p>100
(3.2.1-1)
(3.2.1-2)
Where: p——soil resistivity (ohm-meter); R——grounding resistance value (ohm);
S——grounding interval (kilometer).
Article 3.2.2 The grounding resistance value of the metal sheath of overhead cables and their steel strands shall not be greater than that specified in Table 3.2.2.
Grounding resistance of overhead cable metal sheath and its steel strands Soil resistivity (ohm-meter)
Grounding resistance value (ohm)
100<≤300
300<500
Article 3.2.3 When cathodic protection is used for underground cables, the grounding resistance value of the cathodic protection equipment shall be determined based on the required discharge flow of the cable and the soil resistivity of the location of the cathodic protection equipment, taking into account the grounding resistance value and the power consumption value of the cathodic protection equipment.
Article 3.2.4 When anode protection is used for underground cables, the anode grounding resistance value shall be determined based on the type and length of the cable to be protected. Section 3 Grounding resistance of poles, open wires and terminal equipment Article 3.3.1 The grounding resistance values of various groundings of poles and open wires shall not be greater than those specified in Table 3.3.1.
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