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The insulation resistance for class I appliances should not be less than
7 Mega ohm
2 Mega ohm
7K ohm
2K ohm
2 Mega ohm
According to the Indian Electricity (IE) Rules and relevant BIS standards (such as IS 302 for household appliances), the minimum insulation resistance for Class I appliances must be 2 M╬й. This standard ensures that leakage current is kept within safe limits to prevent electric shock and equipment failure.
According to the Indian Electricity (IE) Rules and relevant BIS standards (such as IS 302 for household appliances), the minimum insulation resistance for Class I appliances must be 2 M╬й. This standard ensures that leakage current is kept within safe limits to prevent electric shock and equipment failure.
RinsтАЛ=IleakтАЛVtestтАЛтАЛ тАФ The fundamental relation defining insulation resistance where VtestтАЛ is usually 500V DC for standard testing.
Insulation resistance serves as a barrier against leakage current flow from live parts to the exposed metal enclosure (earth). By maintaining a resistance of at least 2 M╬й, the potential difference across the insulation is controlled, ensuring the leakage current (IlтАЛ=V/RinsтАЛ) remains well below the hazardous human sensation threshold under normal operating voltage.
Class I appliances require an earth connection for safety.
The insulation test is conducted using a Megger or insulation tester.
A value of 2 M╬й is the minimum requirement to prevent tracking and breakdown.
Higher resistance values indicate better quality insulation and safety.
Ensures safety of personnel by preventing electrocution.
Protects against short-circuit faults during equipment operation.
Insulation degrades over time due to thermal stress and humidity.
Difficult to measure in highly contaminated environments.
Testing of industrial motors and household appliances.
Safety auditing for electrical installations in residential buildings.
IE Rules mandate periodic testing of electrical installations to ensure the insulation resistance does not fall below specified safe limits.
Option 7 M╬й is unnecessarily high as a minimum standard; 2 M╬й is the industry-standard threshold for Class I portable appliances.
B is correct тАФ The minimum permissible insulation resistance for Class I appliances is 2 M╬й to ensure operational safety.
Always remember that insulation resistance tests are performed with DC voltage (usually 500V) to avoid capacitive charging currents associated with AC testing.