Self test technology 2 pole 40A BR style breaker Replaces the GFCB240 Replaces the GFCB240 with new Self Test functionality. UL performed a study that found there were devices in the field that had gone "brain dead" and could no longer protect against electrical shock and leakage current, but were still functional. As a result of the study, UL required that all new GFCI devices perform a routine self-test of their capability to detect and prevent ground faults. The device must disable itself if the self-test is failed. The self-test software runs in the background-it will be invisible to the user when the self-test program is running. All Eaton devices will maintain their TEST buttons to manually test the device. Pressing a breaker's TEST button will yield the expected result: the breaker will trip if it is functioning properly. GFCIs are required in any application near water such as kitchen countertops, bathrooms, swimming pools, hot tubs, and outdoor receptacles. They immediately break the circuit when electrical current leakage is being detected, reducing the risk of shock and electrocution.