Is urban public transport (for example, buses) protected from lightning strikes at their home locations and is it necessary at all? Lightning protection is necessary! In addition to the parking of vehicles, bus fleets also carry out vehicle maintenance and repair, which means that there are personnel and equipment. In this case, it is impossible to do without grounding and lightning protection.
The ZANDZ Technical Center received the task to calculate lightning protection of the bus fleet, which is located in the European part of the Russian Federation. The engineers of the technical center offered the following solution:
- object: bus park;
- dimensions: 160 mx 130 m;
- maximum height: 16.85 m;
- soil resistivity: 100 Ohm * m.
Calculate the grounding and lightning protection system for the bus park using lightning protection mesh.
Lightning protection and grounding of the parking are performed in accordance with:
- EIC "ELECTRICAL INSTALLATION CODE" 7th ed;
- IS 153-34.21.122-2003 "INSTRUCTIONS FOR LIGHTNING PROTECTION OF BUILDINGS, STRUCTURES AND INDUSTRIAL COMMUNICATONS", hereinafter IS;
- AD 34.21.122-87 "INSTRUCTION ON LIGHTNING PROTECTION OF BUILDINGS AND STRUCTURES", hereinafter AD.
The object refers to III category of lightning protection in accordance with AD and to "ordinary" in accordance with IS.
The set of measures on the provision of the necessary requirements to the grounding device is presented by the following solutions:
1. Lightning protection is carried out with the help of a lightning mesh with the distance between the meshes of 10 m. The mesh is made of steel copper-bonded wire (the tickness of the copper coating is not less than 70 mcm), the diameter of the wire is d8 mm (GL-11149).
2. Copper-bonded steel wire is used as down conductor (thickness of the copper coating not less than 70 mcm), d8mm wire (GL-11149).
3. Installation of down conductors is carried out with the help of clamp GL-11747А on the roof, GL-11703А - on vertial surfaces. Distance between the clamps- from 0.8 up to 1.0 meter.
4. To connect rolled metal over the length and in the nodes, a universal clamp GL-11551A is used.
5. All metal elements, placed on the roof must be connected to the down conductor with the help of clamps GL-11545А. Stairs and hand railings are connected with the help of a clamp-bridge GL-11514.
6. Grounding is made in accordance with AD, p.2.26. A copper-bonded steel tape with a cross-section of 30x4 mm laid along the contour of the object is used as a horizontal ground electrode system. The distance to the object foundation- not less than 1 m. Burial depth of the tape 0,5-0,7 m.
7. In accordance with the EIC-7 ed., p.1.7.55 - Grounding devices for protective grounding of electrical installations of buildings and structures and lightning protection of the 2nd and 3rd categories of these buildings and structures, as a rule, should be common.
8. Calculated value of the grounding device resistance - 0,47 Ohm.
9. If there are metal reinforce concrete framings, they must be connected to down conductors/ grounding device..
10. Connection to the grounding device is carried out with the help of clamps ZZ-005-064.
Grounding device resistance calculation:
The design resistance of the grounding device is 0,47 Ohm.
Условные обозначения – Type Codes
Проволока стальная омедненная диаметром 8 мм – Steel copper-bonded tape 8 mm in diameter
Полоса стальная омедненная сечением – Steel copper-bonded tape with the cross-section of 30* 4mm
Универсальные зажим-соединитель для проволоки – Universal clamp for wire
Зажим для подключения проводника – Clamp for connecting conductor
Опуск токоотвода – Down conductor down drop
Equipment arrangement layout is shown in figure 1.
Figure 1 - Layout of equipment arrangement of lightning protection for a bus park.
The list of required material is given in Table 1.
Table 1 - List of material needs.
|Item.||Product item||Name||Quantity, pcs.||Mass, kg||Note|
|1.||GL-11149-50||GALMAR Copper-bonded wire (D 8mm / S 50 mm²; coil of 50 meters)||90||0,41||In meters|
|2.||GL-11545A||GALMAR Clamp on the gutter for a down conductor (painted galvanized steel)||50||0,112|
|3.||GL-11551A||GALMAR Clamp for connecting down conductors (painted galvanized steel)||420||0,07|
|4.||GL-11747A||GALMAR Clamp on the roof covered with metal profiles / corrugated sheets, for down conductor (painted galvanized steel)||4800||0,05|
|5.||GL-11703A||GALMAR Clamp to the facade for down conductor with its elevation above the clamp to 15 mm (painted galvanized steel)||600||0,02|
|6.||GL-11514||GALMAR Clamp-bridge on a gutter for down conductor (tinned copper)||50||0,076|
|7.||GL-11075-50||GALMAR Copper-bonded tape (30 * 4 mm / S 120 mm²; coil of 50 meters)||16||0,98||In meters|
|8.||ZZ-005-064||ZANDZ Clamp for connecting conductor (up to 40 mm)||90||0,312|
Do you have questions or need to calculate lightning protection and grounding for a bus park? Send your request to email@example.com.