The ZANDZ Technical Center has received a request for the calculation of a lightning protection system for a crate designed for 4 dogs. Let us consider the solution that was proposed by our engineers.
Source data:
- architectural drawing;
- roofing plan;
- soil resistivity: 100 Ohm * m.
Task:
- calculate external lightning protection system;
- calculate grounding device.
Lightning protection and grounding of the crate for dogs is made in accordance with:
- Electrical Installation Code EIC 7th ed.;
- S 153-34.21.122-2003 "Instructions for lightning protection of buildings, structures and industrial communications", hereinafter IS;
- AD 34.21.122-87 "Instruction on arrangement of lightning protection of buildings and structures", hereinafter AD.
A set of measures to ensure the necessary requirements for a lightning protection system and the grounding device of a multifunctional complex is represented by the following solutions:
- Lightning protection of the object is made using lightning rods with a height of 2 m (GL-21131).
- Deflectors are protected by metal caps, which are connected to the down conductor system.
- Steel copper-bonded wire d8 mm (GL-11149) is used as a down conductor (thickness of the copper bonding at least 70 mcm).
- Installation of down conductors is carried out with the help of clamp GL-11711 - on a flat roof, GL-11703A -on vertical surfaces. Distance between the clamps- from 0.8 up to 1.0 meter.
- A universal clamp GL-11551A is used for connecting the mill products along the length and in the nods.
- All metal elements, placed on the roof must be connected to the down conductor with the help of clamps GL-11545A.
- Copper-bonded steel electrodes 3 m long are used in places of downdrops as vertical ground electrodes. 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. Deepening of the tape 0,5-0,7 m.
- 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.
- If there are metal reinforce concrete framings, they must be connected to down conductors/ grounding device.
- Connection to the grounding device is carried out with the help of clamps ZZ-005-064.
- Density of lightning strikes into the ground - 4 strikes / sq. km per year
- The total number of strikes into the system - 0,0052 (once in 192 years);
- The total number of breakthroughs is 0,00022 (every 4545 years);
- The reliability of the system is 0.958;
- Probability of breakthroughs into all the system objects - 0.042.
The resistance calculation of the grounding device:
Vertical electrode resistance:
- where ρэкв - equivalent soil resistivity - 100 Ohm*m;
- L - vertical electrode length - 3 m;
- d - vertical electrode diameter - 0.014 m;
- T - deepening - the distance from the ground surface to the ground electrode system - 2 m;
where t is the deepening of the electrode top - 0,5 m
Horizontal electrode resistance:
- where ρ - equivalent soil resistivity - 100 Ohm*m
- b - width of the horizontal electrode - 0.03 m;
- h - horizontal electrode laying depth -0.5 m;
- Lгор - the length of the horizontal electrode is 21 m.
Impedance of the grounding device:
- where n - number of kits, vertical ground electrodes -3 pc., horizontal ground electrode - 1 pc. ;
- Kисп utilization ratio, 0.81.
- The design resistance of the grounding device is 5,94 ohm.
Figure 1 shows the arrangement of equipment.
Figure 1 - Location of equipment.
The list of required material is given in Table 1.Table 1 - List of materials needs.
| № | Product item | Name | Quantity, pcs. | Mass, kg. |
Note |
| 1. | GL-21131 | GALMAR Air terminal-mast on a concrete base (2,0 m; on one concrete base; galvanized steel) | 4 | ||
| 2. | GL-11149-50 | GALMAR Copper-bonded wire (D 8mm / S 50 mm²; coil of 50 meters) | 1 | 0,41 | Weight is given per meter |
| 3. | GL-11545A | GALMAR Clamp on the gutter for a down conductor (painted galvanized steel) | 5 | 0,112 | |
| 4. | GL-11551A | GALMAR Clamp for connecting down conductors (painted galvanized steel) | 10 | 0,07 | |
| 5. | GL-11711 | GALMAR Clamp on a flat roof for the down conductor (plastic, concrete) | 40 | 1 - 1,2 | |
| 6. | GL-11703A | GALMAR Clamp to the facade for down conductor with its elevation above the clamp to 15 mm (painted galvanized steel) | 20 | 0,02 | |
| 7. | GL-11075-20 | GALMAR copper-plated tape (30 * 4 mm / S 120 mm²; coil of 20 meters) | 1 | 0,98 | Weight is given per meter |
| 8. | GL-11075-10 | GALMAR Copper-bonded tape (30 * 4 mm / S 120 mm²; coil of 10 meters) | 1 | 0,98 | Weight is given per meter |
| 9. | ZZ-001-065 | ZANDZ Copper-bonded threaded grounding rod (D14; 1.5 m) | 6 | 2,00 | |
| 10. | ZZ-002-061 | ZANDZ Threaded coupler | 4 | 0,08 | |
| 11. | ZZ-003-061 | ZANDZ Starting tip | 3 | 0,07 | |
| 12. | ZZ-004-060 | ZANDZ Driving head for jackhammer | 2 | 0,09 | |
| 13. | ZZ-005-064 | ZANDZ Clamp for connecting conductors (up to 40 mm) | 8 | 0,16 | |
| 14. | ZZ-006-000 | ZANDZ Conductive grease | 1 | 0,10 | |
| 15. | ZZ-007-030 | ZANDZ Waterproof tape | 3 | 0,40 | |
| 16. | ZZ-008-000 | ZANDZ Header for a jackhammer (SDS max) | 1 | 0,50 |
Do you have questions about lightning protection and grounding of a dog crate? Contact the ZANDZ Technical Center !
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