Abstract: Equipment is provided to test an electrical device, e.g. solenoid, or heater that effects an operation, e.g. movement of a valve, heating etc. To perform a test, the equipment actuates the device to cause the operation to commence. When the operation has proceeded to a predetermined extent, or after a predetermined time, whichever occurs first, a signal is produced which causes de-actuation of the device thus stopping the operation. A signal is also produced to indicate whether it was the elapse of the specified time or the operation proceeding to the specified extent that caused de-actuation. The equipment is particularly suited for testing a device forming part of a trip system.