S S Earthing
In Electrical Engineering, earth or ground is the reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the earth. In an electrical installation, an earthing system or grounding system connects specific parts of that installation with the Earth’s conductive surface for safety and functional purposes. After explaining what earthing is, this article will focus on the purpose of earthing/grounding, good earthing practices (approved earthing) and the main components, design and functions of an earthing/ grounding system.
In mains powered equipment, exposed metal parts are connected to ground so that if, due to any fault conditions, a “line” supply voltage connection occurs to any such conductive parts, the current flow will then be such that any protective equipment installed for either overload or “leakage” protection will operate and disconnect the line voltage.
This is done to prevent harm resulting to the user from coming in contact with any such dangerous voltage in a situation where the user may, at the same time, also come in contact with an object at ground/earth potential. Connection to ground also limits the build-up of static electricity when handling flammable products or electrostatic-sensitive devices.
Neutral Earthing
In neutral earthing, the neutral of the system is directly connected to earth by the help of the GI wire. The neutral earthing is also called the system earthing. Such type of earthing is mostly provided to the system which has star winding. For example, the neutral earthing is provided in the generator, transformer, motor etc.
Equipment Earthing
Such type of earthing is provided to the electrical equipment. The non-current carrying part of the equipment like their metallic frame is connected to the earth by the help of the conducting wire. If any fault occurs in the apparatus, the short-circuit current to pass the earth by the help of wire. Thus, protect the system from damage.