Ideal 61-051 Fast & simple testing and fault identification in 3-wire. 125V circuits without probes or meters. Tests for open ground. Reverse polarity. Open hot. Open neutral. Hot & ground reversed. Hot on neutral. & hot open. E-Z Check Plus (61-051) intentionally overloads the actual GFI breaker to test its mechanical operation in addition to checking for proper wiring sequence. UL listed. CSA rated.