Abstract: A power fault testing apparatus for testing telecommunications interfaces to BellCore's 2nd Level AC power fault standards. The apparatus is powered by a three-phase 480 VAC, 600 A power service. A plurality of transformers and load resistor banks are coupled to the power source in a network organized as a plurality of selectable and switchable power paths for interfacing to tip-and-ring interfaces or broadband coaxial cable interfaces of telecom equipment. Power relays are provided for interconnecting the transformers and load resistor banks in the network arrangement. Computer-controlled output relays are included for effectuating precise, repetitive time duration control of output power applied to the telecom interfaces under test.