Power Surges and Spikes by Brandy McNeilin GuidesFebruary 17, 2017 What are They? Power surges are an increase in the voltage that powers electrical equipment. Surges often go unnoticed, often lasting only 1/20th of a second, but they are much more common and destructive than you might think. According to recent studies, electrical equipment is constantly experiencing surges of varying power. Some of them can be absorbed by a power supply while others can only be handled by a quality surge suppressor. The most destructive power surges will wipe out anything that gets in their way! Where do they come from ? In this power-hungry computer age, utility power systems are often pushed beyond their capacity, resulting in unstable, unreliable power for consumers. Overburdened power grids can generate powerful surges as they switch between sources or generate “rolling surges” when power is momentarily disrupted. Local sources can also generate surges (such as a motor starting, or a fuse blowing out). What about Lightning? Lightning can generate a spectacular surge along any conductive line to destroy everything in its path. No matter what manufacturers may claim, no surge suppressor in the world can survive a direct lightning strike. However, with quality equipment the surge suppressor will take the hit – ending up melted – but the equipment it protects will not be affected. Choosing the Right Level of Protection Joule Ratings: The bigger, the better! Joule ratings measure a surge suppressors ability to absorb surges. 200 Joules: Basic Protection 400 Joules: Good Protection 600+ Joules: Excellent Protection Surge Amp Ratings: Higher ratings offer more protection. Amp levels are another important factor in determining surge strength. Look for the highest amp protection levels available. UL 1449 Voltage Let-Through Ratings: Underwriter Laboratories tests each surge suppressor and rates them according to the amount of voltage they let-through to connected equipment. The lower the let-through voltage, the better the surge suppressor is. UL established the 330 volt let-through as the benchmark because lower ratings added no real benefits to equipment protection, while surge components, forced to work harder, failed prematurely. Be wary of manufacturers claiming lower let-through ratings.