Model MS-2A is capable of testing the time-delay characteristics of overcurrent relays, motor overload relays and molded-case circuit breakers rated up to 125 amperes, when following the recommended test procedure of testing the time delay of these devices at three times their rating. Higher currents are available for the short durations required to test an instantaneous trip element. For example, the test set will provide a maximum short duration output of 750 amperes through a typical, 125 ampere, molded-case circuit breaker. The MS-2A is ideal for testing ground fault protection devises with window CTs. The NEC 230.95C requires specific ground fault devices be performance tested when initially installed. The MS-2A is commonly used by many utilities and service organizations as a economical light weight overcurrent relay test system. Additional applications include verifying the ratio of current transformers and testing panelboard ammeters and voltmeters.