Which test is used to verify the functionality of circuit breakers?

The most suitable test for verifying the functionality of circuit breakers is the functional or operating tests. These tests are specifically designed to assess whether a circuit breaker operates correctly under various conditions. During a functional test, the circuit breaker is subjected to its operational parameters to evaluate its ability to open and close in response to fault conditions, ensuring it will trip when necessary to protect the circuit from overloads or short circuits.

Functional tests simulate real-world conditions to ascertain that the mechanism responds properly, including checking the trip settings and ensuring that the breaker can be reset after tripping. This is essential for confirming that the breaker will perform its protective role when needed, thus ensuring safety and reliability in the electrical system.

In contrast, calibration tests are more focused on ensuring that measurement devices are providing accurate readings. Resistance tests measure the resistance of the contacts within the circuit breaker but do not assess the actual operational response of the breaker itself. Voltage drop tests typically evaluate the voltage loss across a device under load conditions rather than the operational functionality of circuit breakers. Thus, the functional or operating tests are crucial for verifying that circuit breakers will operate as intended in a protective capacity.