Eaton 9155 UPS (8–15 kVA) User's Guide 164201553 Rev G (www.eaton.com/powerquality) 17Chapter 5 Input Isolation Transformer InstallationThe Eaton 9155 has the following power connections: 2‐phase (L1 and L2), neutral, and ground connection for rectifier/bypass input 2‐phase (L1 and L2), neutral, and ground connection for load outputC A U T I O N The input isolation transformer output is always 240V (180° phase angle). If installing a Maintenance Bypass Module (MBM) or Power Distribution Module (PDM), the UPS MUSTbe set up for 240V output only; otherwise, the “Bypass Not Available” alarm annunciates. Any equipmentconnected to the output requiring 208V (120° phase angle) is at risk for damage when using themaintenance bypass switch. The input isolation transformer cannot be used with a wall-mounted bypass switch.Output overcurrent protection and disconnect switch must be provided by others.Figure 12 and Figure 13 beginning on page 22 show the oneline diagrams of the inputisolation transformer with the UPS.W A R N I N GOnly qualified service personnel (such as a licensed electrician) should perform the UPS installation andinitial startup. Risk of electrical shock.To hardwire the input isolation transformer and UPS (all hardware is supplied in theaccessory kit):1. Verify that the electrical connections to the installation site have been properlyinstalled.2. A wall-mounted, user‐supplied, readily‐accessible disconnection device must beincorporated in the input wiring.Compare the circuit breaker ratings and wire sizes to the specifications in Table 2on page 19.NOTE To accommodate the feature of easy system expandability, it is recommended that initial installationof the Eaton 9155 UPS contain wiring to support the maximum capacity of the UPS cabinet.3. Switch off utility power to the distribution point where the UPS will beconnected. Be absolutely sure there is no power.4. Determine your equipment's grounding requirements according to your localelectrical code.5. Verify that the UPS battery circuit breaker is in the OFF position (see Figure 9).6. Verify that the input circuit breaker is in the OFF position.7. Remove the UPS wiring access cover and retain.8. Remove the input isolation transformer wiring cover and retain.