Power basics for IT professionals
technology brief
Abstract.............................................................................................................................................. 2
Introduction......................................................................................................................................... 2
General terms ..................................................................................................................................... 2
Power generation, transmission, and distribution ..................................................................................... 3
Generation and transmission ............................................................................................................. 3
Present-day power distribution infrastructure ........................................................................................ 4
Regional power distribution............................................................................................................... 5
Power distribution at the site.............................................................................................................. 5
Power factor correction................................................................................................................... 14
Leakage current ............................................................................................................................. 15
Grounding .................................................................................................................................... 15
Power utilization ................................................................................................................................17
Three-phase versus single-phase power............................................................................................. 17
Panel distribution ........................................................................................................................... 18
Distribution within the rack .............................................................................................................. 19
Uninterruptible Power Supplies (UPS)................................................................................................ 20
Wiring methods ............................................................................................................................. 21
High-line or low-line input voltage .................................................................................................... 23
Inrush current................................................................................................................................. 23
Plugs and receptacles ..................................................................................................................... 24
Power trends and strategies ................................................................................................................ 24
Tools for powering the data center....................................................................................................... 26
Appendix A. United States design standards......................................................................................... 27
Appendix B. Voltages and frequencies of individual countries................................................................. 28
Appendix C. Plug and socket types...................................................................................................... 31
Glossary........................................................................................................................................... 35
For more information.......................................................................................................................... 44
Call to action .................................................................................................................................... 44