Earthing Design Calculation, Lightning Protection System

Description

What is Earthing or Grounding?

A safety measure devised to prevent people from getting shocked if the insulation inside electrical devices fails is called Earthing. To answer our initial question, the third pin in the plug is actually the “Earth” or “Ground” connection of the electrical appliance.

The Earth, being a good conductor of electricity, acts as a convenient path for the flow of electrons that escape the insulation. Furthermore, the gigantic size of the Earth paves a path for the safe discharge of the electric charge.

In technical terms, Electrical Earthing can be defined as the process of transferring the immediate discharge of the electrical energy directly to the Earth with the help of the low-resistance wire. The electrical earthing is carried out by connecting the non-current-carrying part of the equipment or the neutral part of the supply system to the ground.

As stated earlier, earthing provides a simple path for the leakage current i.e., the current that escapes from a device if there’s any fault in the insulation. The short circuit current (current that follows the path of least resistance) of the equipment passes to the Earth, which has zero potential, thus protecting the system and equipment from damage.

Why is earthing necessary?

• Human Safety

• Safety of Electrical Equipment

• Protection of Buildings from Lightning

Types of Earthing methods

• Plate earthing

• Pipe earthing

• Rod earthing

• Water main method

What is a lightning protection system?

Lightning protection systems are used to prevent or lessen lightning strike damage to buildings. They protect the internal electrical components of a building, helping to prevent fires or electrocution. Lightning protection comes in the form of a lightning conductor, usually a metal rod, mounted on a building to protect it from lightning strikes. The system will intercept a strike so if lightning hits the building, the lightning rod will be hit first, causing the strike to be conducted through a wire, and passing through to the ground safely.

In a lightning protection system, the lightning rod is a single component of the system. The lightning rod requires a connection to earth to give a building protection. Lightning rods come in many different forms, including hollow, solid, pointed or rounded. All lightning rods are made of conductive materials, such as copper and aluminum.

Because of the high energy and current levels associated with lightning a lightning protection system can never guarantee complete safety from the effects of lightning. In a lightning protection system, the current will divide to follow every conductive path to ground but even the divided current can cause damage. These secondary “side-flashes” can still cause a fire, blow apart brick, stone, or concrete, or injure anyone within a building.

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