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Whole House Surge Protectors: How Effective Are They?

Don’t count on power strips to safeguard your home and fragile electronics. Read on to learn about the cost-saving alternative of installing a home surge protector.

Plugs In Electrical Power Strip

Not long ago, electrical contractor Allen Gallant was about halfway through the job of completely rewiring a 3,200-square-foot house in Acton, Massachusetts, when the owners decided to save some money and not install whole house surge protection against surges from lightning or downed power lines.

Sure enough, soon after the house was finished, Gallant got a phone call from the distressed owners: Lightning had struck a utility pole near their house, sending a tidal wave of voltage through the wires, past the main breaker panel, and into the house.

Power Strip
Power Strip What it does: Provides basic protection for multiple devices. Look for: Switches for each outlet; space between outlets for three-pronged plugs and transformers; indicator lights to show if unit has worn out; clamping voltage of 400 volts or less. Cost: $20-$40

“It burned out the motherboard in the Sub-Zero refrigerator, fried the temperature controls in the double-wall oven, killed six dimmers, two computers, and every GFCI plug in the house,” Gallant says. “It was an $11,000 loss.”

Many homeowners believe that adequate surge protection begins and ends with plugging their computer into a power strip. Unfortunately, that’s seldom the case.

First of all, not all surge protectors live up to their name; some are little more than glorified extension cords. Second, a surge will follow any wire into a house—phone and cable lines included—and threaten fax and answering machines, televisions, satellite systems, computers, and modems. And third, as the owners in the Acton remodel discovered, delicate electronic circuitry has proliferated throughout our homes, leaving common appliances as vulnerable as computers to the effects of surges.

What Causes Power Surges

A power surge may last for only a few millionths of a second, but at its worst, it carries tens of thousands of volts, enough to fry circuit boards, crash hard drives, and ruin home-entertainment systems.

Lightning-induced surges are the most powerful and most feared: A 200,000-amp jolt crashing through a power line will burn standard 20-amp wiring like a lightbulb filament. But a lightning strike has to be less than a mile from the house to cause harm, and in fact, most surge-related damage is not caused by lightning.

Surge Station By APC
Surge Station What it does: Protects phone lines and coaxial cable, in addition to plug-in devices. Look for: A clamping voltage of 330 volts of less; built-in thermal fuses. UL 497A for surges through telephone lines and UL 1283 for electromagnetic and radio interference. Cost: $40-$70

Far more common, if not as dramatic, are surges caused by downed power lines, sudden changes in electricity use by a nearby factory, or even the cycling on and off of laser printers, electric dryers, air conditioners, refrigerators, and other energy-sucking devices in the home.

The damage inflicted by these minor power fluctuations can be instantaneous—but may not show up for some time. “You might not even notice it,” says Andy Ligor, a consultant with A.M.I. Systems Inc., a firm that installs both residential and commercial surge-protection systems. “Then a year or so later your microwave stops working.”

Power Surge Protectors

Guarding against surges requires a two-pronged approach: a whole-house suppressor to tame the big, dangerous power spikes and an individual circuit (or “plug-in”) surge suppressor for vulnerable appliances and electronic devices.

Both types essentially act like pressure-relief valves. Normally they just sit there, allowing electric current to flow through them. But with higher-than-normal voltage, the devices instantly divert excess voltage to the ground wire. (The best ones react in less than a nanosecond.) As soon as voltage levels return to normal, the flow of electricity is restored, unless the surge was big enough to melt the fuse built into some units.

Whole-Home Surge Protectors

Typically, whole-house suppressors are hard-wired to the service panel, a process that takes a licensed electrician about two hours. Whole-house systems should be rated to stop a 40,000-amp surge, at minimum. Features to look for include thermal fuses, and lights or alarms that indicate when a device has taken a hit.

Protection for an average house with 200-amp service will run about $500—including a couple of hours of an electrician’s labor. Separate but smaller whole-house units are recommended for the phone and cable lines. These protect fax and answering machines, televisions, and modems.

By themselves, whole-house suppressors can’t stop surges completely; up to 15 percent of excess voltage may leak by. That’s where “plug-in” surge protectors come in. These buffers between individual appliances and wall outlets come in a bewildering array of options and prices. They range from $70 units not much bigger than a computer mouse to $350 units the size of a pizza box that guard all the components in a home theater.

Circuit Protectors

UPS (Uninterrupted Power Supply)
Uninterruptible Power Supply What it does: Supplies clean, fluctuation-free power. Battery backup buys time to save data during a power outage. Look for: Indicator lights for burned-out fuses; phone and cable connectors. Make sure it’s plugged into its own power strip. Cost: $150-$350

But most plug-in models fall into three basic categories: the familiar multi-outlet power strip; the multitasking surge station that can handle phone and cable jacks as well as power cords; and the UPS (uninterruptible power supply), which completely cleanses electric power of random fluctuations and provides a short-term battery backup in case the power dips or goes out entirely.

Expect to pay between $20 and $70 for a quality power strip or surge station, and from $100 to $350 for a UPS.

Buying Circuit (Plug-in) Protection

Before buying a plug-in unit, check that it does the following:

  • Meets UL Standard 1449 (second edition)
Has a clamping voltage—the amount that triggers the diversion of electricity to the ground—of 400 volts or less. The lower the number, the better the protection

  • Absorbs at least 600 joules of energy
Protects all three incoming lines: hot, neutral, and ground. Look for “L-N, L-G, N-G” (line to neutral, line to ground, neutral to ground) on the product’s spec sheet
Stops functioning when its circuits are damaged by a surge

Both whole-house and plug-in types can get zapped without your knowing it; look for indicator lights that signal when a unit no longer works.

Even the best surge suppressor can’t do its job if the house wiring isn’t properly grounded; there has to be a single way for the diverted electricity to go. “Without a good ground, the current may follow another wire and end up inside your modem or fax machine,” says Tom Plesich, director of business development at Innovative Technology, a maker of surge-suppression equipment.

Also, avoid plugging surge-sensitive electronic devices into the same power strip with laser printers, air conditioners, or other appliances with large motor loads. These produce their own low-level power surges that will affect all the devices sharing the strip.

Insurance companies don’t typically give discounts for surge-protected homes, but investing in protection may very well pay for itself, and then some. That’s what the owners of the house in Acton discovered—too late.

How Much Do Whole-House Surge Protectors Cost?

Whole-House Suppressor
Whole-House Suppressor What it does: Stops surges from entering house wiring. Separate devices needed for power, phone, and cable lines. Look for: A rating between 20,000 and 40,000 amps; internal fuses and failure-indicator lights. Cost: About $200 per unit plus two hours for electrician to install
Michael Heiko

When Allen Gallant returned to the surge-damaged site, he spent an hour and a half installing a whole-house system that included a panel-mounted, whole-house surge suppressor and similar devices for phone and cable lines.

The new wall ovens ($3,000) are now safe from surges, as are the repaired Sub-Zero refrigerator ($1,200) and all of the house’s other electronics. Total bill from Gallant: $940.

Where to Find It

Power strip:

Powermax 8 Multi-use AC Surge Protector by Panamax Inc.

Surge station:

SurgeArrest Surge Protector Pro8TV
 by American Power Conversion (APC)

Uninterruptible power supply (UPS):

Back-UPS VS 500 by APC

Whole house suppressor:

Primax GB13, Panamax, Inc.

Specialized protection:


SurgeArrest Notebook Surge Protector PNotePro3 by APC
Computer networks:

ProtectNET Thinnet Port Surge Protector (for 10 Base2 Lan equipment) by APC

Telephone, computer, or fax lines:
MAX 2Tel by Panamax
Home entertainment and audio/video systems
MAX 5100 by Panamax

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