Data centers consume tremendous amounts of power, on the order of 100 to 200 times the power that a typical office building consumes. In 2013, data centers consumed an estimated 91 billion kilowatt-hours (kwh) of electricity, a number that is expected to grow to 140 billion kWh by 2020. The impact of electricity costs on operations can be dramatic, especially in large data centers where a single facility may consume on the order of thousands of gigawatt (GW) hours per year. To be energy efficient and reduce wiring costs, power distribution units are located close to servers and other loads. The units receive power from the UPS at 480 V (400 V outside the United States) and distribute it at 208/230 V. While this structure results in less energy loss and lower utility bills, it distributes the risk of electrical arc flash.
Arc flash happens when electricity jumps across a gap from a conductor to ground or another phase. If sufficient current is available, the arc can quickly escalate into an explosion. In the United States, five to 10 arc flash incidents occur each day (across all industries), causing costly equipment damage and downtime. Fortunately, the majority of these events occur when workers are not present, but when they are, arc flash is known to severely injure and kill workers through burns, ruptured eardrums, collapsed lungs, and shrapnel emitted at ballistic speeds.