Tripp Lite "N+1" Single-Phase UPS systems feature two redundant power modules—each sharing an equal percentage of the load. One power module can be removed for maintenance (in a fully-powered, hot-swap condition) and the other power module will automatically support the load. No user action is required to shift support of the load to the redundant power module. It is important to guard against UPS system overload, the UPS system can only provide redundancy at half of its kVA capacity. For example, a 12 kVA model provides redundancy up to 6 kVA; a 16 kVA model provides redundancy up to 8 kVA; and a 20 kVA model provides redundancy up to 10 kVA. If the load exceeds half of the UPS's capacity and one power module is removed for maintenance, the remaining power module will sense an overload and automatically switch into internal system bypass: passing through utility power, when available, but not supplying battery backup support until the overload is removed, at which time the UPS will automatically switch off system bypass and resume normal operation.