A Tier-III or Rated-3 data center rating, as defined by the multiple expert bodies, requires that the Data Center has redundant power and cooling systems to ensure high availability and uptime. Specifically, a Tier-III/Rated-3 data center must have dual-powered cooling equipment and multiple independent distribution paths serving the IT equipment.
While having parallel paths of electric supply can improve the redundancy and reliability of a data center’s power system, it is not strictly required for a data center to achieve a Tier 3 rating. Rather, Tier 3 requires that the data center has multiple independent distribution paths, which can be achieved through a variety of means such as redundant transformers, generators, and uninterruptible power supply (UPS) systems.
That being said, having parallel paths of electric supply can be a useful way to further enhance the redundancy and resiliency of a data center’s power infrastructure, particularly in situations where one power path may be unavailable due to maintenance, repair, or other issues.
