A Relay Tester is someone who tests or modifies developmental and operational electrical machinery. This high-demand professional also handles electrical control equipment and circuitry in industrial or commercial settings. They generally work under the direction of engineers or technologists.

The professional is responsible for the field technical training for other Relay Testers. They have to take care of the relaying schemes, metering, remote control, data systems, and hydroelectric generator control. The Relay Tester has to work in close coordination with other departments to ensure the integrity of the electric system.