Question 273Electricity & Electronics - Assistant Engineer

The correct answer is C) portable low voltage high current testing unit. A portable low voltage high current testing unit is the appropriate device to check the calibration of a circuit breaker. This type of unit can accurately measure the current at which the circuit breaker trips, allowing the operator to verify that the breaker is calibrated and functioning properly within the specified parameters. The other options are not suitable for this task. A 500 volt megohmmeter (A) would not provide the necessary high current output to test the circuit breaker. A standard digital multimeter (B) does not have the capability to generate the high current required. A clamp-on voltmeter (D) can measure voltage, but not the current needed to test the circuit breaker's calibration.