Surge Protectors: The Numbers You Need To Know - Arvig Blog
Surge Protectors January 9, 2018

Surge Protectors: The Numbers You Need To Know

Devices are affordable, effective against power surges, but they’re not all alike

Written by Arvig in Home Technology for Your Home

By Broch Paplow

Surge protectors are often confused with a separate, but look-alike component: the power strip. Though both function similarly, each has a different purpose.

Power strips and surge protectors both have multiple outlets to power electronic devices, but only the surge protector is designed to offer significant protection from power surges. Standard power strips have only a minimal capacity to block surges, and serve mainly as an extension of a wall outlet.

A power surge is a momentary spike in electricity caused by a short circuit, tripped circuit breaker or lightning strike. Surges can overload and damage circuits in electronic devices. It takes only a fraction of a second for a jolt to render an electronic device beyond repair, so it’s wise to connect electronics to a surge protector to prevent damage.

Surge protectors capture and suppress excess voltage before it reaches connected devices. Anything connected to power: computers, gaming consoles, televisions, cable and satellite receivers, home theater systems and office equipment can be damaged by voltage spikes. The same goes for smartphones, routers and even power tools. Large appliances such as air conditioners, refrigerators and ovens are also susceptible to damage, since many modern units now have electronic systems and computer chips.

Surge protectors are affordable and widely available online or at home electronics stores, but before you make a purchase, there are a set of important labels on the device to consider.

First, the level of protection offered by surge protectors is measured in energy units called joules—the higher the number, the better the protection. Here’s some context: 60 joules is equivalent to a 60-watt light bulb that is on for one second.

Surge protectors vary. You’ll typically pay more for a higher joule level, but more joules will better protect certain electronics. Experts and manufacturers generally recommend a unit with up to 1,000 joules for small electronics, and 1,000 to 2,000 joules for office equipment, routers and power tools. Surge protectors with top-end joule ratings—2,000 and above—are ideal for computers, gaming consoles and home theater systems. The joule rating should be printed on the package.

There are other important labels you should watch for, too. Look for the device’s clamping voltage rating. That is the minimum voltage the surge protector will detect before it blocks a surge. In this case, lower numbers are better, but a surge protector with clamping voltage of 400 volts or fewer is considered adequate.

Also important is to check for the Underwriter’s Laboratories seal. This is the independent testing authority’s official label, certifying the device as capable of projecting electronics from power surges.

Some final considerations—some surge protectors offer warranty protection for properly connected electronics. Warranty period and coverage amount depend on the surge protector.

Also, surge protectors, like remote batteries or light bulbs, have a limited lifespan. Repeated surges stress the protective hardware, and eventually, it burns out. Most surge protectors include diagnostic indicators that light up when the system is functioning properly.

Do you have further questions? Chat with us at, or watch our how-to video on this topic.