Striking the right balance between availability, safety and cost in a power distribution system, especially where UPSs are involved, is a complex calculation – and one that changes as the critical load grows.

Mission-critical power systems require feeds from different power sources. These must interact with each other, as well as with switchgear along the power distribution system paths and branches to the critical load elements. Failure to consider how the UPS interacts with the power distribution system can cause safety risks and unreliability. It’s complicated further by changes in behaviour during nominal current, overcurrent and short-circuit current conditions.

This data center white paper looks at these topics, as well as the importance of selectivity and making correct choices between 3- and 4-pole switching and their consequences for safety and regulatory compliance.