Wiring Activity (KOQ)

Wiring is a necessary to every household and industry to get a constant power supply and prevent from electrocuted. In this subject i learn on how to make a proper wiring  and get a lot of knowledge on types of switches that play role in distribution box (DB).We study about single phase current because most of housing area are equipped with single phase current and it is reliable and cheap for housing area. Besides, an Earth-leakage circuit breaker (ELCB) is a safety device used in electrical installations with high Earth impedance to prevent shock. It detects small stray voltages on the metal enclosures of electrical equipment , and interrupts the circuit if a dangerous voltage is detected. Once widely used, more recent installations instead use residual current circuit breakers which instead detect leakage current directly. For MCB, There are two types of operations of an MCB. The first depends on the thermal effect of over - current. The other depends on the electromagnetic effect of the over - current.
Thermal effect: When over - current flows, the bimetallic strip, owing to the thermal expansion of metals, is heated and deflects by bending. The deflection in the strip, releases a mechanical latch which is also connected with the MCB circuit opening mechanism and this opens the contacts of the MCB, disconnecting the faulty circuit. Electromagnetic effect: In this case, there is an electromagnetic displacement of the plunger (solenoid) of the MCB. It then strikes the trip lever that releases the mechanical latch and thus opening the contacts of the MCB.
The MCB can be operated manually as well. For Operating Mechanism: It allows the manual opening and closing. The MCB has three positions of operation : ON, OFF and TRIPPED. If the device is manually closed, it shows ON position. If the device is manually opened, it shows OFF position. If the device has tripped due to some electrical fault, it shows TRIPPED position. For Tripping Mechanism: It is the principle component of an MCB. It mainly consists of the bimetallic trip circuit (thermal) and the electromagnetic trip circuit (electromagnetic). The bimetallic trip circuit provides protection against over - load while, the electromagnetic trip circuit provides protection against short circuit.