Molded case circuit breaker testing encompasses dealing with a wide range of amperages as breakers are specifically designed to handle particular loads and applications. The trip characteristics therefore vary with amperages as low as five amperes and reaching the high ends of 2000 to 3000 amperes. Using NEMA AB 4 as our test procedure, each breaker is put through a battery of tests to verify that mechanical operation, contact resistance, insulation resistance, instantaneous trip (short circuit trip), and thermal trip (over-current trip) characteristics are in conformance with the generally accepted testing parameters as established by the industry. The image shown here is a smaller bench-top high current test set, the Multi-Amp MS2, which we use for testing molded case circuit breakers ranging from five to sixty amperes. All tested/re-qualified molded case circuit breakers are backed by our 1 year replacement warranty.