Mill-type DC relays are constructed for steel panel mounting with front connections. Each unit circuit block has a two-pole double break design with captive mounting screws and are interchangeable between relays. DC overload relays are designed for use on DC power circuits to monitor DC motor loading. Inverse time limit trip relays are normally set to trip between 125% and 175% of full load motor current. Instantaneous trip relays are normally set to trip between 200% and 300% of full load motor current.