The unpredictable threat of transient overvoltages is ever increasing in today's low-voltage power supplies for every aspect of industry. To calculate the magnitude, duration and energy of such transient overvoltages is not an easy task. Some loads are becoming very sensitive to such overvoltages, thereby creating a challenge for the application engineer to design a reliable power supply system. To apply surge overvoltage mitigation devices requires technical knowledge to understand their application limitations and configuration within a power system. A technical overview of the fundamentals of transients and associated noise is presented. The importance of understanding applicable UL, IEEE, and IEC Standards, and a thorough review of manufacturers' data on transient voltage surge suppressors (TVSSs) is included. TVSS testing requirements per the second edition of UL 1449 is presented. An overview of how to design a low-voltage power supply system to suppress transient overvoltages is included.