So, now that we know the requirements of a true surge/spike protector, we can now go shopping for the one that is right for our needs. What would you buy Brent? Glad you asked! I have purchased and only recommend SurgeX. Why? The SurgeX surge protection technology was designed to handle the indirect surges, and this technology has been verified by UL for 1000 such surges. The odds of you using this unit up are nil, unless you live in Tampa, FL, in the highest unprotected structure in town.
SurgeX uses Series Mode surge suppression. They act first as low pass filter, blocking the high-frequency components of surges. The remaining low-frequency surge energy is stored in capacitors, for the duration of the event. Then it is slowly discharged back across the incoming hot and neutral conductors without involving any connection to equipment ground. SurgeX units can be placed anywhere along a power circuit without the ground reference elevation disadvantage of Shunt Mode surge protection devices.
All other manufacturers use Metal Oxide Varistors (MOV's). These are the main components that divert incoming surge energy into the equipment ground. In all Shunt Mode surge suppressors, they have a "fixed clamping voltage" characteristic, above which they rapidly change from virtual open circuits into low resistance conductors. For a transient surge duration of not more than a few milliseconds, the resulting power dissipation in MOV's can be tolerated. In the event of a continuous surge of any significant duration, MOV's rapidly heat up and then either permanently revert to their non-conductive state, or fail, possibly catching fire.
No matter who makes it, or how much they cost, the sacrificial effect of repeated surges over time will ultimately cause MOV's to fail one way or the other. Recent MOV-based surge suppressor devices made to Underwriters Laboratories (UL) 1449-2 (2nd ed.) specifications incorporate a fuse element which disconnects the power in the event of catastrophic MOV failure. Older MOV-based devices do not have this feature, however, and non-catastrophic MOV failure leaves the attached equipment completely unprotected, usually without the knowledge of the owner! To ensure continuously safe operation, MOV-based surge protection devices should be tested on a regular basis.
Why buy any other unit than a SurgeX? Glad you asked. SurgeX is the only company that does not use radial-lead MOVs, that does not contaminate the ground, does not have to switch on, and last but not least, does not need to be tested. I would encourage you to protect yourself, in storm season and out of storm season with a SurgeX.