The communication cabinet is designed to collect, perform intermediate processing, temporary storage, and transfer of information. They are often installed in a server room. But, sometimes, there is no space, and communication cabinets are installed on the roof near the reception mast. The ZANDZ Technical Center has received a request to calculate the lightning protection for the communication cabinet located on the building roof in Almaty. Let us continue with more detailed review of our offered solution.
Calculation of lightning protection for the communication cabinets on the building roof in Almaty
Facility: communication cabinets on the building roof in Almaty
Figure 1. Facility plan.
Task: to perform calculations for the lightning protection system for the communication cabinets on the building roof in Almaty
Solutions to ensure the requirements of the lightning protection system for communication cabinets on the building roof in Almaty:
- The lightning protection is made in accordance with the Electrical Installations Code (EIC), Rev. 7, SO 153-34.21.122-2003 Guidelines for Lightning Protection of Buildings, Structures, and Industrial Utilities (hereinafter referred to as SO) and RD 34.21.122-87 Guidelines for Lightning Protection of Buildings and Structures (hereinafter referred to as RD).
- The facility is classified as Category III of the lightning protection. The system reliability should be at least 0.9 according to RD.
- According to SO 153-34.21.122-2003, item 22.214.171.124, and RD 34.21.122-87, item 1.6, the masts are used as natural lightning arresters.
- A copper-plated steel wire (copper coating thickness of at least 70 μm), d8 mm (GL 11149), is used as a current collector.
- Down conductors are installed using the GL-11711 clamp on a flat roof, and GL-11703A for installing downdrops along the walls. The accepted pitch of terminals is 0.8-1.0 m.
- The universal terminal GL-11551A is used to connect rolled products along the length and in joints.
- 2 x 3 m vertical electrodes are used as a grounding arrangement, which are combined by a horizontal electrode (copper-plated bar 30 x 4 mm). The distance between vertical electrodes is at least 5 m. The distance from the horizontal electrode to the object is at least 1 m, penetration is 0.5 – 0.7 meters.
- Grounding arrangement connections are made using clamps ZZ-005-064.
Figure 2 shows hardware layout.
Table 1 includes the list of required hardware and materials.
Мачта - Mast
Условные обозначения - Legend
Горизонтальный заземлитель - Horizontal grounding electrode
Зажим для подключения проводника - Wire connecting clamp
Вертикальный электрод длиной 3 м - 3 m vertical electrode
Проволока стальная омедненная диаметром 8 мм - Steel copper-plated wire 8 mm
Зажим-хомут - Collar clamp
Опуск токоотвода - Downdrop
Figure 2. Layout of equipment for lightning protection of communication cabinets at the building roof in Almaty.
Internal lightning protection (surge protection):
1. To protect 0.4 kV power supply circuits, three-phase Class 1+2+3 SDPs PowerPro BCD TNS are installed at each power terminal input from the transformer substation and backup power supply (DES).
2. To protect Ethernet data transfer circuits, SDP DataPro x8RJ45-19'' is installed to protect twisted pair cable with RJ45.
DataPro 10LSA (PTC) is installed to protect lines in LSA modules.
3. To protect POE-based IP cameras, SDPs DataPro RJ45 PoE Alu are installed, and from the switch side, SDP DataPro x8RJ45-19'' can be installed.
4. Equipment protection in automation, regulation, and control networks is performed using SDPs MP 2 x 2 DGT +12V-Ad-Ad-Pg ST and MP 2x2 GDT +24V-Ad-Ad-Pg ST in 12 V and 24 V circuits, respectively, which are installed at the base MP Base 2 x 2-R GDT as well as using SDP DataPro x 8RJ45-19''.
Table 1. List of materials needed for all building sections.
Do you have any questions regarding lightning protection of communication cabinets on the roof or other facilities? Please, contact the ZANDZ Technical Center!