Siemens QF120A 20 Amp Single-Pole GFCI Circuit Breaker 120VTesting GFCIs and afcis on a monthly basis is a good idea that is sometimes forgotten. Underwriters laboratories (UL) suggests that afci GFCI Devices be tested every 30 days after installation to ensure they are properly working. Now the new self test & lockout feature enables the dual function circuit breaker to automatically and continuously test itself to ensure that it is working properly. If it is detected that the device has been compromised,