A reverse fault current interruptor (RFCI) may be employed in one or more locations in an electrical power system. In one example, an RFCI may be installed in a combiner box of a solar power system. The RFCI may include a reverse current detector and a circuit protector such as a circuit breaker, operable in combination to clear a line-line fault in the combiner box. The RFCI enables a reduction of incident energy levels through detection of a reversal in a fault current characteristic of some DC power systems, where a traditional overcurrent protection device (OCPD) (e.g., fuse, breaker) may not trip in the same period of time.