Power distribution unit branch protection

An apparatus and system are disclosed for protecting a power distribution unit from an electrical fault. A fuse interrupts a flow of electrical current in response to the electrical current rising above a current rating of the fuse. A current sensor measures the amplitude of the electrical current and outputs a current amplitude signal. A relay interrupts the flow of electrical current in response to an OFF signal. A fault module receives the current amplitude signal and sends the OFF signal to the relay in response to the amplitude of the electrical current exceeding a threshold value. The relay, the fuse, and the threshold value are selected so that a switching time of the relay is less than an opening time of the fuse for an amplitude of the electrical current between the threshold value and a maximum fault current value, so that the relay prevents the fuse from opening.