How Is Proper Grounding Performed?

The implementation of grounding systems according to standards and taking engineering calculations into account is of great importance. Indeed, a poorly executed grounding system poses a significant risk. As Lightning Protection Center, we work on ensuring the application of standards in grounding. If we explain the grounding topic within the relevant standards TSE 62305-1-2-3-4, EN 50164-1-2, it is particularly important to keep the earth resistance as low as possible in areas where people and animals are present.

You May Be Interested: Grounding Measurement Report

Keeping grounding resistance as low as possible reduces side flashes and hazards in lightning protection systems during atmospheric electric discharges. In areas where there is a danger for humans and animals, the earth resistance of each grounding electrode system should not exceed 10 ohms. Any further reduction is advantageous. Generally, grounding installations are carried out using one of the following methods:

• Grounding system with rod electrode
• Grounding system in tripod shape
• Grounding system with plate electrode
• Grounding system with strip electrode
• Grounding system with metal electrodes
• Grounding system with underground water pipes
• Building enclosure electrode grounding system

Correct grounding protects you and your buildings.

Points to Consider Regarding Grounding

Regardless of the shape of the grounding installation, the grounding electrode should be located outside the area enclosed by the building foundations. Also, all underground networks (electricity, water, gas) around the grounding system, even if not entering the building, should ideally be at least 5 meters away for safety. Long metal poles, tower cranes, lighting towers, cranes used in shipyards and ports, long lifting vehicles, and other structures should be grounded according to TSE 622 standard rules to ensure adequate lightning protection.

Ground electrodes must consist of at least the following dimensions:

• Conductor forming a closed loop with a length not less than 20 m.
• Vertical rods and pipes with a total length not less than 9 m.
• Radial conductors with a length not less than 20 m.

You May Be Interested: Equipotential Grounding Bar

Some buildings may have a surrounding grounding installation within the soil. This installation is usually made of copper or galvanized strip and surrounds the building about 1 meter from the foundation. The ohm resistance of this type of grounding is lower than that of the lightning rod system. However, if a grounding suitable for the lightning rod in every aspect is required, a separate grounding should be implemented.

Various methods can be applied to reduce grounding resistance.

The building’s grounding system and the lightning rod grounding should be equipotential and connected to each other. If sensitive devices such as computers are connected to the building’s main grounding, the two groundings can be considered independent. To fully isolate the two grounding systems, the distance between them should be at least 10-20 meters.

Measures to Reduce Grounding Resistance

If possible, one of the following soil types should be selected:

• Wet swampy soil.
• Clay, muddy soil, tillable soil, clayey soil, clay mixed with small amounts of sand or mud.
• Clay or mud mixed with varying proportions of sand, gravel, and stones.
• Moist and wet sand.
• Avoid dry sand, gravelly chalk, limestone, granite, very stony soil, and areas with young rocks close to the surface.

Increasing Moisture Content: The soil around the electrode is moistened with river or groundwater. Optimal conditions are achieved when soil moisture reaches 15-25% of soil weight, halving the grounding resistance.

Salt Addition: Adding salt equal to half the water weight (approximately 0.1% of soil weight) further reduces resistance by 20%. Table salt, rock salt, and copper sulfate can be used. Since water washes away the salt around the electrode, three times the calculated salt amount should be stored near the electrode as backup. If heavy underground water flows from rain or snow melt are expected, salt addition will not be effective.

Adding Humus or Topsoil: Suitable for rocky or stony soil. Coal containing sulfur should not be used. Charcoal addition is very beneficial. Coating the electrode with lead or zinc has no effect on resistance, only prevents corrosion.

Free Water: Lakes, rivers, ponds, or puddles. The electrode should be placed on wet soil, not directly in the water.

Building Enclosure: In extremely adverse conditions, a building enclosure grounding system is installed around the facility to be protected without insulation.

Additional Grounding: Additional grounding electrodes can be installed to expand the ground surface or connect electrodes to nearby water pipes, forming a grounding network.