All Tripp Lite 3-Phase UPS Systems feature manual bypass as well as automatic static bypass to ensure 100% availability of connected equipment by safely passing through AC power if the UPS system requires maintenance. Tripp Lite's External Maintenance Bypass Panels are designed for those who want to "harden" the power distribution system and provide an additional level of external bypass. All Tripp Lite External Maintenance Bypass Panels utilize a key switch interlock configuration (Kirk Key Interlock) as an additional safety measure to increase the system reliability and minimize sequencing errors during maintenance and service operations. Models are available for all 3-Phase UPS Systems: 20, 30, 40, 60 and 80 kVA.