Siemens GFCI circuit breakers are UL Listed and cUL Certified to provide Class A GFCI protection. Current imbalances of 4-6 mA or more between load conductors will cause the ground fault sensor to trip the circuit breaker. These circuit breakers offer Self-Test and Lockout features as required by UL 943, enabling the GFCI to automatically and continuously test itself to ensure that it is working properly. If it is detected that the device has been compromised, the device trips itself signaling to the homwoener it must be replaced to help guarentee the best protection. 10,000 AIR rated breaker and designed for use with 120/240-Volt AC systems.