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Systems that specify two power cords can be brought up with one power cord and continue to run. 

The larger systems that have a minimum of four BPR pairs that are installed must have four power cords installed. Systems that specify four power cords can be started with two power cords on the same side  with sufficient power to keep the system running. 

Power cords attach to a three-phase, 50/60 Hz, 200 - 480 V AC power source, or a 380 - 520 V DC power source. 

A Balanced Power Plan Ahead feature is available for future growth, which helps to ensure adequate and balanced power for all possible configurations. With this feature, system downtime for upgrading a server is eliminated by including the maximum power requirements in terms of BPRs and power cords to your installation. 

For ancillary equipment, such as the Hardware Management Console, its display, and its switch, more single phase outlets are required. 

The power requirements depend on the cooling facility that is installed, and on the number of CPC drawers and I/O units that are installed. For more information about the requirements that are related to the number of installed I/O units, see 10.1.2, “Power requirements and consumption” on page 391. 

## 2.8.2 High Voltage Direct Current power feature 

The High Voltage Direct Current power feature is an option for z14 servers. It allows z14 servers to directly use the high voltage (HV) DC distribution, as shown in Figure 2-26. A direct HV DC data center power design can improve data center energy efficiency by removing the need for a DC-to-AC inversion step. 

<img src='content_image/973876.jpg'>

The z14 bulk power supplies were modified to support HV DC, so the only difference in the shipped hardware to implement this option is the DC power cords. Because HV DC is a new technology, multiple proposed standards are available. 

