Surges (transients) are abnormally high, quick pulses that substantially exceed the normal operating voltage of a circuit. Surges are generally random. They can last anywhere from a billionth of a second to a few thousandths of a second.

A direct lightning strike to a structure has no defense!

Near misses that hit power service poles, where the equipment itself does not receive the direct discharge have a defense. The surge/spike will enter the equipment through the building wiring. The Institute of Electrical and Electronic Engineers (IEEE) compiled research on lighting induced surges outside and inside buildings. The results of this research is documented in C62.41-1991. Research shows that because of arc-over at the service entrance and within the building wiring, the maximum voltage that reaches a 110V outlet is 6000V. The maximum current is 3000A. If a typical 20,000 amp lightning strike occurs up to 1/2 mile away from your facility, the electric and magnetic fields surrounding that strike would induce hundreds of volts into your AC wiring.

Any equipment with an inductor (motor, transformer, coil) like a refrigerator or air conditioner, create a back-feeding EMF when the inductor is switched off. The EMF voltage can be several times that of the original voltage prior to being switched off. These are short transients. The transients can cause similar damage to lightning. Sometimes the damage is degrading circuits over time, only to rear its ugly head in the worst possible moment. I have experienced this personally.

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.

Brent Handy
HA! Handy Audio!
918-664-4952
www.homepage.mac.com/brenthandy/