Question 169Electricity & Electronics - QMED

The correct answer is A) portable low voltage high current testing unit. To check the calibration of a circuit breaker, a portable low voltage high current testing unit is the appropriate device. This type of testing unit can apply a high current load to the circuit breaker, allowing the technician to verify that the breaker trips at the correct current rating as specified by the manufacturer. The other options are not suitable for this task. A clamp-on voltmeter (B) can measure voltage but cannot apply a high current load. A 500 volt megohmmeter (C) is used to test insulation resistance, not circuit breaker calibration. A standard digital multimeter (D) also cannot apply the necessary high current load required to test a circuit breaker's calibration.