UPS INSTALLATION PLAN AND UNPACKINGEATON Eaton 9395 550/275 UPS (225–550 kVA) Installation and Operation Manual 164201716 Rev 2 www.eaton.com/powerquality3-203.2.4 Distributed Bypass Power Wiring PreparationRead and understand the following notes while planning and performing theinstallation: All distributed bypass UPS rectifier inputs must come from one source and allbypass input feeds must come from one source. All UPSs in the distributed bypass system must contain the same number ofUPMs. Mixed UPS kVA ratings are not permitted. Distributed bypass UPS input wiring size requirements and output wiring sizerequirements from the UPSs to the tie cabinet or distribution panel are the same aslisted in Table 3‐4 on page 3-9 and Table 3‐6 on page 3-11. If the load requires a neutral, a bypass source neutral must be provided. If the loaddoes not require a neutral and there is no neutral conductor connected at thebypass input, a neutral to ground bonding jumper must be installed. Install neutralconductors from the UPSs to the common point of connection (tie cabinet), andthen install a system neutral to ground bonding jumper. The bonding jumper mustbe copper wire. DO NOT install both a source neutral and a bonding jumper.If the recommended system neutral bonding jumper installation method cannot beaccomplished, each UPS should have a separate neutral to ground bonding jumperinstalled. See Table 3‐4 or Table 3‐6 for UPS neutral bonding jumper wire sizes. Thebonding jumper must be copper wire. DO NOT install both a source neutral and thebonding jumper.C A U T I O NHIGH IMPEDANCE GROUND SOURCES - If the supply source is a high impedance ground (IT) type, the inputneutral conductor must be connected from the source of supply. If there is no output neutral connected tothe UPS, the neutral‐forming transformer kit may be used instead of pulling a neutral from the source. If theload requires a neutral, then an input neutral conductor must be pulled into the UPS. In no circumstancesshall a neutral to ground bonding jumper be installed in the UPS.C A U T I O NDELTA SOURCES (TN‐S) - The 9390 UPS system can be operated only from a delta supply source that is fullyfloating and if the neutral‐forming transformer kit is installed in the UPS. The UPS cannot be operated from amid‐point or end‐point grounded delta supply source. With this type of supply source, there is no capabilityto provide an output neutral. In no circumstances shall a neutral to ground bonding jumper be installed in theUPS. MOBs with dual auxiliary contacts are to be provided by the customer. Table 3‐16on page 3-17 lists the recommended rating for the MOBs.The tie cabinet must contain Module Output Breakers (MOBs) with dual auxiliarycontacts for control of the system. Without dual auxiliary MOBs, UPMs are notallowed to go to bypass individually during servicing. All UPMs will go to bypassinstead of the just the UPM needing service, decreasing critical load protection.With dual auxiliary MOBs, one UPM can be bypassed while the remaining UPMssupport the load as long as the remaining UPMs have the capacity to do so.
