Abstract: A method and apparatus for rejection of an inappropriate rating plug in an electronic trip unit for a circuit breaker including: a microprocessor programmed to determine an overcurrent condition of the circuit breaker; a nonvolatile memory in operable communication with the microprocessor; the rating plug releasably engaged with the microprocessor, the rating plug includes an identification register; wherein the microprocessor reads the identification register, the identification register includes an identification number; wherein the microprocessor accesses one of a plurality of programs in the nonvolatile memory based on the identification number; and wherein the one of a plurality of programs instructs said microprocessor to perform a validation of said rating plug for operation with said microprocessor.