Types of Grounding

The process of connecting inactive parts in electrical installations, neutral conductors, and the parts connected to them to the earth by means of an electrode in a conductive manner is called GROUNDING. In soil layers with different specific resistances, the aim is to calculate the number and shape of the electrodes to be used according to the desired resistance value and the function of the required grounding, and to obtain the desired earth resistance value by ensuring conductive contact with the soil.

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SOIL RESISTIVITY MEASUREMENT

Article 10/c-5.i.1 of the Regulation on the Preparation of Electrical Internal Installation Projects dated December 3, 2003 requires the determination of soil resistivity before starting projects.

In soil resistivity measurements, it is possible to use various classical methods such as Wenner, Schlumberger, dipole-dipole, single electrode-dipole, half Wenner, and half Schlumberger. All of the traditional methods mentioned above are applied by driving 4 measurement stakes into the ground at different intervals along a straight line.

The expert engineering and implementation team of the Lightning Protection Center provides project design, implementation, measurement, and material supply support in grounding applications.

While specially developed measuring devices are used for measurements carried out at small intervals, the voltmeter-ammeter method is used for measurements carried out at large intervals. In electrical methods, electric current is injected into the ground via two stainless metal-steel electrodes driven into the soil. The voltage difference generated underground is measured using two electrodes placed at two other points on the surface. You can see the measurements of some soil types in the table below.

If any device or motor in a facility fails, followed by failures in other motors or devices, and no abnormality is detected in the system voltage, and the source of the failures cannot be identified,
If electric shock occurs when touching METAL REINFORCEMENTS within the facility,

It can be stated that there is a grounding fault in the facility and necessary precautions must be taken urgently.

TYPES OF GROUNDING

Protective Grounding

This is the grounding of inactive parts of operating equipment in order to protect people against dangerous touch and step voltages. Protective grounding is one of the methods of protection against contact voltage in low-voltage installations.

Operational Grounding

This is the grounding of the operating current circuit for the normal operation of the installation. In low-voltage networks, it is performed by grounding the neutral points of transformers, or one pole or the middle conductor in DC installations. Thus, the voltage that may occur against the ground in the system is prevented from exceeding certain values.

Functional Grounding

This is the grounding performed to ensure that a communication installation or an operating component performs its intended function. Protection against lightning effects, grounding of rail systems, and grounding of low-current devices are examples of functional grounding.

Foundation Grounding

Foundation grounding increases the effect of potential equalization. When the regulatory rules are fulfilled, foundation grounding is suitable as an earthing electrode in power installations and lightning protection systems.

This grounding is the main part of the electrical installation behind the building connection box or an equivalent installation.

The foundation grounding electrode must be arranged so that it is completely covered with concrete. When a steel strip grounding electrode is used, it must be placed vertically.

The foundation grounding electrode must be interrupted at expansion joints. End points must be brought outside the foundation and sufficiently flexible connections must be made. Connection points must always be accessible for inspection. For foundation grounding, a steel strip with a minimum cross-section of 30 mm x 3.5 mm or round steel with a minimum diameter of 10 mm should be used. Steel may be galvanized or non-galvanized. Connection leads must be made of galvanized steel. Connection parts must be made of corrosion-resistant steel.