Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
For Testing of domestic wiring installationwhich instrument is used?
Neon Tester
Meggar
Plumb bob
Pen Knife
Meggar
A Meggar (Megohmmeter) is the standard instrument used to test the insulation resistance of electrical wiring installations. It detects leakage currents and ensures that the wiring is safe by measuring high resistance values using a high DC voltage.
A Meggar (Megohmmeter) is the standard instrument used to test the insulation resistance of electrical wiring installations. It detects leakage currents and ensures that the wiring is safe by measuring high resistance values using a high DC voltage.
RinsтАЛ=IVтАЛ тАФ Ohm's law applied for insulation resistance measurement
P=VI тАФ Power dissipation across insulation if leakage is high
The Meggar operates on the principle of electromagnetic deflection. It consists of a DC generator (hand-cranked or battery-powered) that produces a high voltage, which is applied across the insulation to measure the resistance using an ohmmeter movement calibrated in Mega-ohms. The insulation resistance is determined by the ratio of voltage to current, given by RinsтАЛ=IVтАЛ.
A Meggar must be operated only when the circuit is de-energized (dead).
Standard insulation resistance should not be less than 1 M╬й as per the Indian Electricity Rules.
A high resistance reading indicates good insulation; a low reading indicates a fault or moisture ingress.
Capable of testing high resistance values which standard multimeters cannot measure.
Self-contained power source ensures testing capability in remote areas.
Cannot be used on energized circuits.
High voltage output can damage sensitive electronic components.
Testing domestic, industrial, and commercial wiring installations.
Preventive maintenance of transformers, motors, and cables.
Neon testers are used only to detect the presence of phase voltage.
Plumb bobs are used for vertical alignment, not electrical testing.
Pen knives are manual tools for wire stripping, not diagnostic instruments.
B is correct тАФ The Meggar is the dedicated instrument designed to measure high insulation resistance by providing a controlled high-voltage output.
Always remember that Meggar readings are valid only when the circuit is isolated from the power supply; testing a live circuit with a Meggar will result in erroneous readings and potential damage to the instrument.