Surge Protector Buying Guide

Surge Protector Buying Guide

Safeguard Your Equipment with the Right Surge Protector

If your shop is like most, you’ve got more things to plug in than outlets to put them in. And, in all likelihood, those things you need to power are expensive and difficult to replace. So, naturally, you need to add more outlets and you need to do it in a way that safeguards your critical equipment.


However, not all surge protectors are created equal. In fact, some can even do irreparable damage. Before you grab any old power strip, let Grainger give you the rundown on what you need to know.

The Basics

Electrical surges happen all the time, and they have a wide range of causes. Lightning strikes, tripped circuit breakers, large equipment on/off cycles and power outages can all wreak havoc, costing you thousands of dollars in a split second.

Surge protectors are designed to handle these irregularities and keep an even flow of power to your devices. Keep in mind that a surge protector and a power strip are two very different things. They may look alike, but a power strip will only add outlets; it won’t offer any protection.


  • Surge Protector Strips plug into any standard outlet and let you plug in and protect several devices at a time
  • Point-of-Energy Surge Protectors are designed to protect your entire facility from external surges.
  • Uninterruptible Power Supplies give your devices a safety net of battery backup at all times. If the power surges, dips or cuts, it will keep them running without interruption for a period of time.
  • Wall-Mount Surge Protectors have no cord. They plug directly into a power outlet and fit snugly against the wall, which is ideal for spaces that can’t accommodate a power strip.


Here’s where surge protectors earn their keep. When you’re browsing for one, you’ll see a number of ratings and indications. Here’s what they mean:


The joules rating tells you how much energy the unit can take before failing. This may be the most important factor in choosing a surge protector—the higher the number, the better your protection will be. For small electronics like clocks or lamps, anything up to 1,000 joules is fine. Power tools, routers and printers need something with a rating between 1,000 and 2,000, while computers, TVs and heavier equipment will require a rating of 2,000 joules or more.

Clamping Voltage

Clamping voltage (sometimes called suppressed voltage or peak let-through) is the point at which your surge protector will kick into gear and start protecting your equipment. Unlike joules, you want a lower number here.

UL Standards

Underwriters Laboratories has created a safety standard called UL 1449 Voltage Protection Rating (VPR). This indicates how much total voltage your protector will allow through to any connected devices. Again, the lower the number, the better your level of protection.

Response Time

Surges don’t happen instantaneously; they can take up to a few nanoseconds. Response time tells you how many nanoseconds it will take for your protector to spring into action. You want to look for something with a response time of one nanosecond or less.

Other Considerations

  • Energy Savers. Some surge protectors allow you to save energy by “turning off” all the connected devices on standby that are drawing energy.
  • GFCI Protection. GFCI protection will automatically detect a short circuit and shut the power off, which could save your facility from an electrical fire.
  • Remote Control. Often, surge protectors are located in hard-to-reach areas, so turning them off or on can be a hassle. If that’s the case, look for a surge protector with a remote control, which can be mounted to the wall for easy operation.
  • Timers. Some surge protectors come equipped with timers you can program to switch on and off at certain times of the day or night.


Pub. 08/2017

The product statements contained herein are intended for informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness for a specific application or use. W. W. Grainger, Inc. does not guarantee the result of product operation or assume any liability for personal injury or property damage resulting from the use of such products.