This unit will prove invaluable for showing applications of electromagnetic devices (the solenoid) and bi-metal strips as well as bringing them all together to demonstrate the key principles of the modern domestic circuit breaker. The apparatus runs on safe, low-voltage DC and shows both a slow overload which operates the thermal trip together with a current surge overload operating the solenoid trip. The unit is contained in a robust tray with acrylic protective cover and requires a 12V DC supply through 4mm sockets.