If Shunt Mode “All three modes” suppressors can actually cause data problems, what should I look for in a powerline surge suppressor?

Experts recommend the Series Mode type for modern computing systems, or any sensitive electronic system that may be interconnected with other electronic systems. A heavy duty surge reactor acts to deflect surges rather than perting surges where they can do further harm.

The following list of specifications should be carefully examined and compared:

  1. Let-through voltage at maximum rated surge (not simply clamping level, which is the onset of clamping) using standard test pulses. (Let-through voltage is the amount of the surge voltage that is let-through to your protected equipment and should be as low as possible. 180 volts is the theoretical lower limit for 120 volt powerlines).
  2. Service life for various surge levels (including maximum rated surge). A service life of 200 minimum worst-case surges is recommended for a five year life in high exposure locations.
  3. Filter response. (i.e. greater than 30 dB at 100 kHz.) The important frequency range for surges is 5 kHz to 500 kHz. Greater than 20 dB at 100 kHz is desirable.
  4. Safety Ground Wire contamination should be avoided if equipment is to be interconnected. Suppressors that claim “all three modes of protection” pert surges to the Safety Ground Wire and should not be used with interconnected equipment.
  5. Self-test or failure indication (not “protection working” indicators which are often little more than power applied indicators).

Do laptop computers require surge protection?

Yes. When laptops are plugged in and connected to the power line, they are just as susceptible to surges as a desktop computer.

Why do you recommend preceding an uninterruptible power supply (UPS) with a Zero Surge power quality filter?

A typical standby UPS lets through 400V or more of surge energy. Surge energy let-through of over 400V can cause damage to sensitive components. Preceding the UPS with a Zero Surge 2R Series product protects the UPS and its connected equipment from the surges that can wear down components over time causing premature failure as well as from catastrophic surges that cause immediate damage.

The National Electric Code regulates against the daisy chaining of plugged in power devices. By rule, any device with three or more receptacles is considered a “Relocatable Power Tap”. You should not connect two or more Relocatable Power Taps into each other (they must be plugged directly into the wall receptacle). The 2R15W has only has two receptacles. It is allowable to plug the 2R15W into the wall outlet with the UPS plugged into the 2R15W. An alternative is to plug the UPS into a branch circuit that is protected by one of our Commercial or OEM products. By code, it is not allowed to use our 6, 8, or 10 receptacle products with a UPS.

Experts say that powerline surge protectors can cause damage to motherboards and data cards, and scramble data sent to interconnected computers, printers and modems. How does this happen, and how can I avoid these problems?

There are basically two types of powerline surge technology, patented Series Mode and the older Shunt Mode (so-called hybrids are usually Shunt Mode). The Shunt Mode technology was developed over thirty years ago to protect standalone equipment, but this older technology is no longer suitable for modern sensitive interconnected equipment.

Shunt Mode protectors are still very common because this older technology is inexpensive to manufacture with high profit margins, and as long as people can be seduced by the low prices, these products will continue to be sold. They generally divert powerline surges to the safety ground wire, using circuits described as “All Three Modes of Protection”. The resulting surges diverted to the ground wire can exceed 1000 volts, exposing sensitive motherboards and data boards to surge disruption, degradation and damage.

This surge voltage on the ground wire varies along the length of the wire. When equipment such as modems, printers and other computers are interconnected, the interconnecting cable creates a “ground loop”. If the surge induced on the safety ground wire of one computer is 1000 volts and the surge induced on the safety ground wire at another location is 600 volts, then the difference of 400 volts is fed into the interconnecting cables causing the disruption, degradation, or damage.

While large surges will cause damage, small surges can result in data problems such as lock-ups, data errors, and “mysterious problems.” It is better to avoid Shunt Mode surge protectors that claim “All Three Modes of Suppression” than to try and live with the problems they cause when they divert surges to the ground wire.


Does surge induced damage occur all at once or over a period of time?

Both ways, depending on the circumstances… A violent electrical storm can induce enough surge energy into powerlines to destroy your computer in an instant, if left improperly protected. Smaller, internally generated surges can, over time, “wear out” delicate circuits, causing intermittent problems, and slowing down the operation of a system. Series Mode surge suppression technology, as designed by ZERO SURGE Inc., employs a surge reactor that serves as a powerline filter, much like the oil filter in your car. The surge reactor filters out damaging energy, just as your oil filter removes impurities that can destroy your engine over time. The result with a good oil filter or a good powerline filter is longer, trouble-free operation.

What type of equipment can be damaged by power line surges?

Any equipment with microprocessors would be considered sensitive and vulnerable to surge damage. Computers, standby uninterruptible power supplies (UPS), audio components, TVs, digital signage, laboratory equipment, controllers, medical devices, fire alarm and security systems are all examples.

Do surges occur when there’s a power outage or brownout?

Yes, surges occur during both events. Typical surge suppressors must reach a fixed clamping level before they recognize the surge. Zero Surge’s wide voltage range dynamic filter in comparison, actively senses surges and operates over a range of 85V-175V, compatible with today’s fixed mode power supplies. This is especially beneficial during brownouts and when standby generators are used.

Do standby generators cause surges?

Standby generators often output variable power (a/k/a dirty power). This is where Zero Surge’s wide voltage range technology is particularly beneficial due to its capability to sense and filter surges over a range of 85V-175V.

How do cable, data, and telephone line surges differ from power line surges?

Unlike power line surges, neither cable, data, nor telephone line surges are generated inside the building. They are only externally generated so the best place to stop these types of surges is where they enter the building. Proper grounding at the service entrance by the service provider is key. Putting cable, data, and telephone line surge protection at the point of use is counterproductive as it provides a path in and causes ground line contamination when it diverts the surge.

What types of problems do surges cause?

Problems can range from “soft” errors where information is scrambled in computing systems to gradual circuit deterioration resulting in premature failure and intermittent operation to outright destruction of circuits.

Why are powerline surges getting worse?

Surge problems appear to be worsening because of the increased use of electronics. As the tiny integrated circuits used in electronics proliferate, more of them are exposed to the dangers of powerline surges.

How large can powerline surges get?

According to industry standards, powerline surges inside a building can reach up to 6,000 Volts, and 3,000 amperes, and deliver up to 90 joules of energy.

How often do surges occur?

Very large storm induced surges occur from a few times a year in medium exposure areas to 40 times a year in high exposure areas, but surges over 1,000 Volts may occur many times a day since they are caused by normal equipment operation.

What causes powerline surges?

Surges can be classified as external and internal. External surges are generally more severe than internal surges while internal surges generally occur more frequently (about 80% of all surges are internal). External surges are frequently caused by storms and normal power company switching operations. Internal surges occur when equipment within the building is cycling on and off.

Surge Protection

Why are Zero Surge suppressors so much better than other powerline surge suppressors?

Other powerline surge suppressors rely mainly on the 50 year old “All Mode” surge suppression technology developed by General Electric in 1972.

The newer, patented Series Mode technology used by Zero Surge limits surge current as well as surge voltage. This technology was developed by J. Rudy Harford, Zero Surge’s founder. It was modeled to provide exceptional performance with interconnected equipment and overcomes the serious shortcomings of shunt suppressors, namely excessive let-through voltage, limited service life, poor filtering, and safety ground wire contamination. Series Mode technology is recommended by experts for modern interconnected computing systems, where reliability and performance are essential.

Can I plug your product into a GFCI or AFCI outlet?

Yes.  Zero Surge’s technology is compatible with GFCI or AFCI outlets.  When using our products in an ungrounded environment, we recommend replacing the receptacle with a GFCI, labeling it as ungrounded.  This adds a level of safety protection should there be a short in the connected equipment. 

My surge suppressor says it meets IEEE-587 specification. Does this mean it’s good?

IEEE-587 specifies test conditions, not performance. Any inexpensive extension cord can claim to meet IEEE-587. It is the detailed results of the testing to the IEEE-587 standard that is important, not the fact it has been tested. 

What does the joule rating of a shunt suppressor mean?

The joule rating is a limitation of the product. Shunt suppressors should not be subjected to surges larger than their joule rating or they will likely fail. Unfortunately, you have no way of knowing in advance how many joules will be in a surge!

ZERO SURGE products do not have a joule rating limitation since they do not work on the diversion principle of shunt suppressors. The series elements internally limit surge current. Even a surge with enough current to blow out the largest shunt suppressor will not harm ZERO SURGE suppressors.

How long do surge suppressors last?

Some surge protectors fail after a single large surge. The largest surge you can expect on a 120 volt powerline within a building is 6,000 Volts / 3,000 Amps according to industry guidelines). Some surge protectors fail in thermal runaway, can overheat and cause fires. 

Before buying a protector, compare rated service life for various surge levels. Do not purchase a surge protector unless it has a stated service life that is reasonable for your application. 

What is meant by the response time of a surge suppressor?

The response time is the time it takes for Shunt Mode protectors to go from an “off” condition to an “on” condition. Unfortunately, some manufacturers state the time for their protector to start coming on as opposed to being completely on, giving a misleading view of actual performance. Zero Surge uses a Series Mode reactor which is always active, so the response time is zero, or instantaneous. 

My equipment has a dedicated powerline. Do I need a surge suppressor?

Yes. A dedicated line can minimize internal surge damage, but provides a direct pipeline for the more dangerous external surges.

Do your products have telephone line and cable protection?

No. Zero Surge does not recommend incorporating cable and telephone line protection at the point of use.

Cable and telephone line protection are frequent add-ons to power line surge suppressors. Users should know that providing an interface between the power line and various cables, as is done in these protectors, is very complex and may be dangerous to your electronics and in some cases, your health!

I have a “whole building” protector, am I adequately protected?

A “whole building” protector generally means protection at the powerline service entrance. A review of the clamping levels for most main panel protectors show their clamp levels to be so high as to be ineffective for sensitive electronics. Whole building protector manufacturers, therefore, recommend supplemental point-of-use protection. Plug-in, point of use protectors with low let-through levels are necessary since they should be the first line of defense for sensitive electronics.

Can I use your products with a whole building surge protector (WBSP)?

Yes.  A WBSP does nothing to protect sensitive electronics, so their manufacturers recommend supplemental point-of-use protection.   Zero Surge products are certified to the lowest let-through level and become the first line of defense from damaging surges generated outside the building.  Zero Surge products also protect from surges generated inside the building that can degrade electronic components, causing premature failure.  In addition to the high let-through levels, WBSPs do nothing to protect electronics from internal surges.

Customer Service

How do I order your products?

You can order right here on our web site by clicking here to visit our online factory store or you can order over the telephone by calling Zero Surge directly at 800-996-6696 between the hours of 8:00 a.m. – 4:00 p.m., Monday – Friday.  Select models are also available from and

Can I order one of your plug-in products with a longer cord?

Please email for pricing and availability on customizing a plug-in model with an 11 ft. or 15 ft. cord (straight plug).

How long will it take to ship my order?

Stock items like our plug-in models, usually ship within 1-3 business days.  Please contact us if you require a more specific turnaround time.

How do you ship your products?

Orders shipped within the United States are shipped via UPS. Online orders to Canada are shipped via US Postal Service.

Is there a warranty on your products?

Yes. Zero Surge Inc. warrants its products to be free from defects in materials and workmanship under normal 120VAC and 240VAC service conditions, including energization by means of the relevant standard 120V or 240V, 60 Hz electrical power, for a period of 10 years to the original holder of the warranty.

Is the warranty on your products transferable?

No. The warranty applies to the original owner only on purchases made directly from Zero Surge or a Zero Surge Authorized Dealer. Zero Surge purchases made on web sites from used equipment dealers or unauthorized dealers are not eligible for warranty service.

How do I register my product for the warranty?

There is no need to register for the warranty. We keep track of purchases by serial numbers in our system. If you purchase from an authorized dealer, please keep a copy of your receipt for verification purposes.

Do you offer discounts on your products?

Quantity discounts are available on purchases of 51+ units. We rarely discount our products due to the cost of our high-performance components and US manufacturing costs. Also, as part of our Quality Assurance Program, we triple test our products which adds to the cost but enables us to offer a 10-year warranty. Having introduced series mode and subsequent related technologies to the marketplace, Zero Surge should be the least expensive option for this technology.

What is your return policy?

Zero Surge has a “no return” policy. Every item is brand new and triple tested before it leaves our facility as part of our Quality Assurance Program. We do not sell refurbished items. Click here to see our terms and conditions.