Electrical safety of public places is very important both during the operation of the facility as a whole, and for its fire safety in particular. Therefore, educational institutions should be protected from direct lightning strikes and have a good grounding device.


The ZANDZ Technical Center received a request to calculate the necessary equipment for lightning protection and grounding of a college in the Siberian Federal District. Further we will study the offer of the technical specialists.


Initial data:

  • object: college;
  • dimensions: 29 mx 20 m;
  • height: 7.5 m;
  • roofing plan;
  • soil resistivity taken as 100 Ohm * m.



  • grounding device resistance should be not more than 4 ohms;
  • сollege lightning protection should be performed using a lightning protection mesh.


Lightning protection and grounding of the college are performed in accordance with:


The object belongs to the "ordinary" in accordance with the IS and to the III category of lightning protection according to the classification of AD.


The set of measures to ensure lightning protection and grounding systems for the college:

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-11711 on a flat roof, GL-11703А - on vertical surfaces and parapets. 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. Copper-bonded steel electrodes 3 m long are used in places of downdrops as a vertical ground electrode. Copper-bonded steel tape with the cross-section of 30x4 mm uniting all vertical electrodes is used as a horizontal ground electrode. 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. The rated resistance of the grounding device is 1.99 Ohms.

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 1,99 Ohm.


Equipment arrangement layout is shown in figure 1

college lightning protection and grounding

Figure 1 - Location scheme of lightning protection equipment and grounding for the college.


The list of required material is given in Table 1.


Chart 1 - List of equipment and materials.

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) 5 0,41 In meters
2. GL-11545A GALMAR Clamp on the gutter for a down conductor (painted galvanized steel) 10 0,112  
3. GL-11551A GALMAR Clamp for connecting down conductors (painted galvanized steel) 35 0,07  
4. GL-11711 GALMAR Clamp on a flat roof for the down conductor (plastic, concrete) 80 1 - 1,2  
5. GL-11703A GALMAR Clamp to the facade for down conductor with its elevation above the clamp to 15 mm (painted galvanized steel) 200 0,02  
6. GL-11514 GALMAR Clamp-bridge on a gutter for down conductor (tinned copper) 10 0,076  
7. GL-11075-50 GALMAR Copper-bonded tape (30 * 4 mm / S 120 mm²; coil of 50 meters) 3 0,98 In meters
8. ZZ-001-065 ZANDZ Copper-bonded threaded grounding rod (D14; 1.5 m) 16 2,00  
9. ZZ-002-061 ZANDZ Threaded coupler 9 0,08  
10. ZZ-003-061 ZANDZ Starting tip 8 0,07  
11. ZZ-004-060 ZANDZ Driving head for a jackhammer 4 0,09  
12. ZZ-005-064 ZANDZ Clamp for connecting conductor (up to 40 mm) 20 0,312  
13. ZZ-006-000 ZANDZ Conductive grease 1 0,10  
14. ZZ-007-030 ZANDZ Waterproof tape 5 0,40  
15. ZZ-008-000 ZANDZ Header for a jackhammer (SDS max) 1 0,50  

Do you have questions or you need to calculate lightning protection systen for a college? Send your request to info@zandz.ru.