by Neil Rasmussen
Alternatives for providing electrical power to high density racks in data centers and network rooms are explained and compared. Issues addressed include quantity of feeds, single-phase vs. three-phase, number and location of circuit breakers, overload, selection of plug types, selection of voltage, redundancy, and loss of redundancy. The need for the rack power system to adapt to changing requirements is identified and quantified. Guidelines are defined for rack power systems that can reliably deliver power to high density loads while adapting to changing needs.
Individual rack enclosure power consumption in the data center or network room varies widely and is expected to grow in the next few years. Rack enclosure equipment is replaced 5 or more times during the life of a data center in a piecemeal manner. This situation requires a rack enclosure power distribution system that can cope with the changing requirements. Key requirements of an effective rack power distribution system were described, which suggest a practical rack enclosure power architecture that can meet the requirements for an adaptable rack enclosure power system. The recommended approach standardizes on four key ways to distribute power, along with a strategy for selection of the best approach for a given installation. When this approach is implemented, the result is a power distribution system which reduces human error, adapts to changing requirements, minimizes the need for advance planning and meets the requirements of high density IT equipment.