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.
- architectural drawing;
- roofing plan;
- soil resistivity: 100 Ohm * m.
- 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.||
|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 !