Circuit Breaker Test Sets are suitable for a wide variety of testing requirements including low-voltage power and molded-case circuit breakers. In addition Circuit Breaker Test Sets are used to test thermal, magnetic or solid-state motor overload relays and other over current protective devices. Tests are performed by simulating an overload or fault condition. Each test set is an integrated test system that provides a variable, high-current output. The test sets incorporate all control circuitry and instrumentation necessary to test direct-acting circuit breakers accurately, efficiently and safely. The time-delay characteristics for long time delay, short time delay and instantaneous trip can be verified. Additional applications include verifying the ratio of current transformers and testing ground-fault trip devices.