For more information about temporary capacity increases, see Chapter 8, “System upgrades”  on page 281. The z14 ZR1 power and cooling system is a change from previous systems because the  system is packaged in an industry standard 19-inch rack form factor for all the internal system  elements. The power subsystem is based on Power Distribution Units (PDUs) that are  mounted at the rear of the system in pairs. The new PSCN structure uses industry standard  Ethernet TOR switches that replace the previous IBM System Control Hubs (SCHs).  The IBM Z systems operate with redundant power infrastructure. The z14 ZR1 is designed  with a new power infrastructure that is based on intelligent (PDUs that are mounted vertically  on the rear side of the 19-inch rack) and Power Supply Units for the internal components. The  PDUs are single phase, 200 - 240 VAC and are controlled by using an Ethernet port.  The power supply units convert the AC power to DC power that is used as input for the Points  of Load (POLs) in the CPC drawer and the PCIe+ I/O drawers. The power requirements depend on the number of PU SCMs that is installed in the CPC  drawer and number of PCIe+ I/O drawers (1 - 4) and I/O features that are installed in the  PCIe+ I/O drawers.  The power subsystem in a z14 ZR1 includes the following main characteristics: The following previous features are not available on the ZR1: 2.8 Power and cooling 2.8.1 Considerations GLYPH<SM590000> Two or four single phase PDUs (200 - 240 VAC, 50/60 Hz), each with a 30A power cord. GLYPH<SM590000> Maximum supported rack power is 9600W. GLYPH<SM590000> No High-Voltage DC power option. GLYPH<SM590000> No three-phase power, no 480 VAC. GLYPH<SM590000> No Emergency Power Off (EPO) switch.  GLYPH<SM590000> No balanced power option or plan ahead power cables (installation of extar PDUs and  PCIe+ I/O drawers is nondisruptive if enough PCIe fanouts are available in the CPC  drawer). GLYPH<SM590000> No Internal Battery Feature (IBF). The standard data center power protection  (uninterruptible power supply based) can be used. GLYPH<SM590000> If the 16U Reserved feature (FC 0617) is installed, the total power consumption for  equipment that is installed under this feature is limited to 3400W. For more information,  see Appendix G, “16U Reserved feature” on page 465.  GLYPH<SM590000> Internal Battery Feature (IBF) GLYPH<SM590000> 480V AC GLYPH<SM590000> High-Voltage DC Power GLYPH<SM590000> Balanced Power, no plan ahead power cords GLYPH<SM590000> external EPO (Emergency Power Off) switch GLYPH<SM590000> Three-Phase Power GLYPH<SM590000> Single SE Display and keyboard, which includes a KVM switch 58  IBM 14 Model ZR1 Technical Guide