When testing a low-voltage power circuit breaker equipped with series trip devices, which test is NOT appropriate?

In the context of testing low-voltage power circuit breakers equipped with series trip devices, the resistance test is not appropriate. This type of testing involves measuring the resistance of a circuit, which typically focuses on confirming good connectivity and low resistance in conductors, rather than evaluating the operational characteristics of the breaker itself.

When testing circuit breakers, it is essential to determine how they respond to various fault conditions and load currents. Short Time Delay, Long Time Delay, and Instantaneous tests are all designed to assess the breaker’s performance in terms of its response time and ability to trip under certain overload or fault conditions. These tests provide insights into the functionality and protective characteristics inherent in the breaker design.

The resistance test, however, does not serve the purpose of validating the operational mechanisms of a circuit breaker. Instead, it could potentially mislead or provide irrelevant information regarding how the breaker will respond in an actual fault scenario, hence its inappropriateness in this testing context.