The electrical systems for data centers are typically robust to better ensure availability and uptime. With the amount of equipment, from transformers, UPS systems, PDUs and more, there is usually a fair amount of electrical resistance losses and sometimes power quality issues. Sometimes these can be spotted with infrared sensors and testing to help find hot spots where excessive losses are occurring. Power quality is another factor in equipment performance that has a direct impact on the energy use, therefore also on the PUE, but also on the equipment longevity. With advancements of servers and other equipment, their sensitivity to non-linear loads (harmonics) has likely increased. That increase can lead to a direct impact on the equipment, causing losses and failures to occur with greater frequency. When reviewing the equipment to be used (such as specifying for new or replacement) for the power system, with the aim for high reliability and availability, it is important to understand beyond the electrical resistance losses and how the greater system will behave.