What is the preferred method of performing primary-injection testing on a low voltage circuit breaker with ground fault protection?

The preferred method of performing primary-injection testing on a low voltage circuit breaker with ground fault protection is by utilizing the manufacturer's test kit or rewiring the neutral CT input. This approach is ideal because it ensures that the testing is conducted with the precise equipment designed for the circuit breaker, which is crucial for accurate measurements and functionality assessment.

Testing circuit breakers, particularly those with ground fault protection, necessitates maintaining the integrity of the ground fault trip settings and ensuring that the circuit breaker responds correctly to overcurrent conditions. The manufacturer's test kit is specifically calibrated to work with the device, providing the necessary features for accurately testing the breaker’s response to various fault conditions, including ground faults.

Using a standard multimeter may not provide adequate depth for this kind of testing, particularly in the context of load or fault conditions, while performing the test without any specialized equipment would likely compromise the safety and accuracy of the results. Connecting two poles in parallel doesn’t apply directly to the method of testing ground fault protection and might lead to misleading assessments or false readings. Thus, choosing the manufacturer's test kit or rewiring the neutral CT input aligns with best practices for assuring the reliable operation of ground fault protection devices.