Quick and easy check for opens or shorts on transformers before energizing. Provides clear indications of open circuits, fast connections, and confirmation that the test results are OK Tests overhead, pad-mount, and other distribution transformers. Tests the primary and secondary sides of de‑energized transformers without disconnecting. Help prevent line workers from installing a fuse on a shorted transformer. Automatic self-test feature Magnet holds the tester in place while testing.