It is necessary to make calculations and make a grounding project for the object.
Object: restaurant with man-made embankment, the height of which is 1 m.
Soil: clay loam.
Soil resistivity: 100 Ohm*m
The calculations were performed in accordance with the EIC 7th ed., IS 153-34.21.122-2003 "Instructions for lightning protection of buildings, structures, and industrial communications" (hereinafter IS) and AD 34.21.122-87 "Instruction for lightning protection of buildings and structures" (hereinafter AD).
The set of measures to ensure the necessary requirements to the grounding device is represented by the following solutions:
- installation of lightning protection wire (d10mm) over the whole area of the roof with the step of 10x10 (see Figure 1, according to the IS 3.3.3.;
- make embranchments from the object to 3 meters with wire (see Fig.1) IS p.188.8.131.52 and unite them by the horizontal ground electrode laid in the ground at the depth of 0,5 m. Only ground electrode, laid in the ground along the external perimeter of the object is considered in the calculation of grounding resistance. The ground electrode on the roof is not considered.
Figure 1. Arrangment of lightning protection and grounding equipment
Молниепримная сетка – lightning protection mesh
Отвод в грунт – drainage to the ground
Зажим для соединения токоотводов (крашенная оцинкованная сталь) – clamp for connecting down conductors (painted galvanized steel)
Проволока омедненная – copper-bonded wire
Бухта - coil
Calculation of grounding device resistance:
- Where ρ - soil resistivity, Ohm*m;
- where D - horizontal electrode diameter, m;
- h - horizontal electrode depth, m;
- Lгор- horizontal electrode length, m.
Calculated resistance of the grounding device is 2,13 Ohm, which is less than the required 30 Ohm.
The list of the required materials
|№ п/п||Fig||Product item||Product||Q-ty|
|1.||GL-11150-50||GALMAR Copper-bonded wire (D 8 mm / S 50 mm2; coil 50 meters)||6|
|2.||GL-11150-20||GALMAR Copper-bonded wire (D 8 mm / S 50 мм2; coil 20 meters)||1|
|3.||GL-11551A||GALMAR Clamp for connecting down conductors (painted galvanized steel)||12|
Appendix: the project is available in DWG and PDF formats
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