Tripp Lite Modular E3 Series 3-Phase UPS Systems can be connected together to provide up to double the capacity of a single UPS. Note, however, that this configuration will not provide external (1+1) redundancy. Remember, the two Modular E3 Series 3-Phase UPS Systems that are connected to the same load must be identical: same model number, voltage, kVA rating, and system level firmware. The maximum number of 120/208 V or 277/480 V model UPSs that can be connected is two. For these voltage configurations, there are only four possible external expansion configurations: 20 kVA UPS + 20 kVA UPS = 40 kVA, 40 kVA UPS + 40 kVA UPS = 80 kVA, 60 kVA UPS + 60 kVA UPS = 120 kVA, and 80 kVA UPS + 80 kVA UPS = 160 kVA. The maximum number of 220/380 V model UPSs that can be connected is four. For the voltage configurations, there are several external expansion configurations (see Tripp Lite UPS Applications group for additional configuration details).