What is the diameter of the power cord for grounding in the lightning protection of the computer roo

The diameter of the round bar should not be less than 10 square millimeters, and the section of the flat steel should not be less than 80 square millimeters.

According to the Code for Lightning Protection Design of Buildings.

According to GB 50057-2010, the special down conductor should be laid along the outer surface of the external wall of the building and should be grounded through the shortest path; When the appearance of the building is high, it can be concealed, but the diameter of the round steel should not be less than the square millimeter, and the section of the flat steel should not be less than 80 square millimeters.

1. Consider the diameter of the grounding wire from the aspect of lightning protection From the aspect of lightning protection, the diameter of the protective grounding wire is easy to be satisfied. Satisfying the discharge of lightning currents is not the main aspect that needs to be considered for the diameter of the grounding wire.

IEC 61312-1 is used as the demarcation line for the selection of lightning protection grounding wire diameter according to whether the overcurrent discharged by a single grounding wire (XJC series grounding wire) reaches 25 direct lightning current. The lightning protection of communication equipment is anti-induction lightning, and if it is directly hit by lightning, it is impossible to carry it in a good lightning protection grounding. Moreover, the requirements for the construction of the communication bureau station are that the building should provide direct lightning protection for the equipment in the computer room, so it is almost impossible for the lightning current discharged by a single grounding wire on the equipment to reach 25 direct lightning current.

According to the requirements of Section 61312-1 of IEC 61312-1, if there is a direct lightning current less than 25 flowing through the equipotential connection conductor (the ground wire of the feeder belongs to the equipotential connection conductor), the conductor cross-sectional area shall meet the requirements of Table 7 of IEC 61024-1. In Table 7 of IEC 61024, it is specified that if the material is copper, the minimum cross-sectional area of the connecting conductor is 6 mm2. If it is greater than 25, the cross-sectional area should meet the requirements of Table 6.

Table 6 of IEC 61024 states that if the material is copper, the minimum cross-sectional area of the connecting conductor is 16 mm2.

Lightning counter calibrator Because it is almost impossible for the lightning current of a single grounding wire to reach 25 lightning currents on communication equipment, the lightning current discharge factors that need to be considered for the protection of the grounding wire of the equipment are easy to be satisfied. Even in some very extreme cases, the lightning current of the equipment protection grounding wire may exceed 25 direct lightning current, and the minimum cross-sectional area of (XJC series grounding wire) is 16mm2 is relatively easy to meet. But if this happens, the equipment is estimated to have been damaged by lightning strikes.

Resistant to accidental external force touch.

If the protective grounding wire is connected from the equipment to the outside of the equipment, it is generally necessary to consider that the protective grounding wire cannot be broken due to unintentional accidental contact by people or other objects. Generally, for a single grounding wire, it is recommended that the wire diameter of the grounding wire (XJC series grounding wire) should not be less than 4mm2. This requirement is also relatively easy to meet.

For Table 3B of GB 4943-2001, the first few wire diameters with small rated current requirements are added, and the notes all indicate that this protective grounding wire is used in the power supply flexible wire, which also considers that the grounding wire should have the basic ability to prevent accidental external force contact and breakage. For example, the diameter of the PE wire in the AC power cord of the computer is far less than 4mm2, and it is gathered in a thicker power cord with the phase wire and the middle wire, which is not easy to break under the touch of external force. But if a single grounding wire uses such a wire diameter, there is a problem.

The lightning protection requirements of the computer room can be lower, because the SPD grounding in the computer room should be regarded as level 3 or level 4 lightning protection, and it is OK to use 16 square multi-strand copper wires; If it is a direct lightning grounding, it is best to use galvanized flat steel or round steel grounding.

There are several kinds of grounding wires in the communication room, 1. The outdoor feeder grounding row is generally grounded with 40*4 galvanized flat iron; 2. Indoor lightning protection grounding, generally 70mm2 below the distribution box; 3. Indoor work DC ground is generally 70mm2; Fourth, the indoor protected area is generally 70mm2Of course, it depends on how the local tender is requested.

That should be at least 10, generally with flat copper.

The diameter of the grounded power cord should not be less than 50 square meters.

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The lightning protection and grounding of the construction of the computer room shall be implemented in accordance with the current national standard "Code for Lightning Protection Design of Buildings".

The specific criteria are as follows:

1. In the first article, four kinds of grounding, such as AC work grounding, safety protection grounding, DC work grounding, and lightning protection grounding, should share a group of grounding devices, and the grounding resistance shall be determined according to the minimum value; If the grounding device is set up separately for the anti-dispatch or lightning calling, the remaining three grounding should share a group of grounding devices, and the grounding resistance should not be greater than the minimum value, and should be in accordance with the current national standard "Building Lightning Protection Design Code" to take measures to prevent counterattacks.

2. Article 1, the electronic computer system that has special requirements for DC work grounding and needs to set up a grounding device separately, its grounding resistance value and the distance between it and the grounding body of other grounding devices shall be determined according to the requirements of the computer system and relevant regulations.

3. Article 1 The grounding of the electronic computer system shall be grounded at a single point and equipotential measures shall be taken.

4. Article When a plurality of electronic computer systems share a group of grounding devices, it is advisable to connect each electronic computer system with a grounding wire respectively. The lightning protection of the factory is divided into the overall structure lightning protection, that is, the lightning protection of the main plant, and the main foundation is grounded electrode and grounding belt to form a grounding network, and the grounding resistance is less than 10 ohms. Then it is connected with the main body of the steel bar or steel structure of the main plant.

The cement concrete roof is connected with a lightning belt or a lightning rod, and there must be a grounding test point on the ground outside the wall group, and the steel structure should be directly led to the roof with galvanized flat iron.

GB 50057-2010 Code for lightning protection design of buildings.

GB 50343-2004 Technical code for lightning protection of electronic information systems in buildings.

GB 50174-2008 Code for design of computer rooms for electronic information systems.

GB50057-2010, GB50343-2004 (GB50343-2011 in December); gb50174-2008；There are other systems involved, such as monitoring systems, cable TV, etc., the key is what equipment you have in the computer room.

Are you monitoring and monitoring room, monitoring room implementation GB50198-2011 civil CCTV system engineering technical specifications just inside the grounding requirements you mentioned MM2 have been mentioned.

What kind of computer room, such as communication room, monitoring room, etc., have different standards, but they are generally the same.

Lightning protection and grounding in the computer room are two concepts. Lightning protection: In order to avoid damage to equipment caused by induction and direct lightning high voltage. Grounding is to prevent the backlog of current from harming equipment and personnel.

There are two kinds of grounding above, one is strong electricity, such as leakage protection! One is weak current, induced current, static electricity, etc. The ground wire of the power cord belongs to the leakage protection type.

Enclosure grounding can be said to be leakage protection and static electricity.

Note: The cabinet shell is not connected in series with power supply equipment such as UPS power supply, and the TV wall is grounded separately.

The requirements for lightning protection in the computer room can be lower, and the change is due to the delay in judging that the grounding SPD of the computer room should be regarded as level 3 or level 4 lightning protection, and it is OK to use 16 square meters of multi-strand copper wire; If it is a direct lightning grounding, it is best to use galvanized flat steel or round steel grounding.