In the real world, well over 80% of transients are generated inside the home/building, almost all are low magnitude, and all propagate throughout the facility as ring wave transients (and even impulse transients are transformed into oscillatory ringing transients as they move throughout the facility because of the impedance inherent in building wiring). Internally generated ring wave transients lock up electronics, cause glitches in operation, and degrade and cause premature failure in power supplies and circuit boards (which necessitate repair or disposal of the electronic based equipment or appliance). If anyone takes a disturbance analyzer (such as Dranetz or BMI) to home, office building, or factory, they would rarely, if ever, find any transients as large as 6000 volts (unless the sub panel was directly feeding equipment or lighting located outside of the building). And, they would almost never find a 6000 volt, 3000 amp impulse transient that forms the basis of the UL Voltage Protection Rating numbers. From our over 35 years of in the field experience, we have found that the vast majority of transients seen inside a facility are ring wave transients less than 1000 volts (and most we find are in the 200 to 500 volt range). Without a good filter, these ring wave transients will adversely affect electronics since almost all of the ring wave transients would be below the turn-on point of the MOVs (Metal Oxide Varistors which are the main components used in panel mounted surge suppression today).
Many SPDs on the market have surge suppression only and will only address certain medium to large impulses. However, externally generated transients such a lightning happen infrequently. But, as long as equipment is operating, internally generated transients are occurring inside a facility and causing gradual degradation to all electric loads. Cleaning up these high frequency but low magnitude ringing transients is the key to reduced maintenance costs, reduced glitches and reprogramming events, and reduced downtime. Most electronic equipment are connected to subpanels. So, the better the ring wave protection of the SPD protecting the panel, the greater the savings to the customer and the quicker the return on the customer’s investment. The enhanced transient filter in the TPS works every second, every minute, and every hour of the day cleaning up the power to give all equipment computer grade power. This is why both the TPS and TPD units extend the life of electronics and allows them to operate with less lockups and glitches. The effectiveness of the enhanced transient filter is of critical value to the home owner or business owner and is the key to savings and return on investment.