Tips for Picking the Right Surge Protector for Electronics

Save your sensitive electronics from damage by following these tips.

Close up of cords plugged into a power strip
Surge protectors and power strips (shown) look like they do the same thing, but only surge protectors are designed to keep electronic equipment safe. Eekhoff Picture Lab / GettyImages

A lot of electronics requires a lot of outlets. With a basic desktop computer, for example, you need an outlet for the monitor, CPU, speakers, wireless router, modem, printer, and any other gadgets you may wish to connect. For a home theater system, there’s the television, stereo receiver, preamp, subwoofer, speakers (sometimes), turntable, DVD or Blu-ray player, gaming consoles, and cable set-top box.

While the typical solution is to get either a surge protector or power strip, these options have important differences to consider. Most surge protectors are also power strips, but power strips are not necessarily surge protectors. You’ll often find them in the same aisle at the hardware or store. But you should know the difference before buying.

What Is a Surge Protector?

While power strips are basically multi-plug extension cords, surge protectors are designed to keep electronic equipment safe from electrical surges or spikes.

Surge protectors work by diverting excess voltage into the grounding port of a wall outlet. Without this feature, the excess voltage would flow through all connected power cables and cause permanent damage to connected devices. The effect of excess voltage can be obvious, like when a light bulb blinks out, or it can be more discreet, gradually weakening circuitry over time. Sophisticated gaming rigs with complex microprocessors may result in terminal failure if power surges or spikes are permitted.

An extreme example of excess voltage is a lightning strike. But you’re more likely to experience electrical surges and spikes when the local utility company switches power grids or has equipment problems. Even though they try to maintain a steady flow of electricity throughout, disruptions sometimes occur.

The most common instance of excess voltage is when there’s a shift in energy demand, especially if the building has old or bad electrical wiring. Ever notice lights flickering or going dim whenever the refrigerator, air conditioner, hair dryer, or other powerful appliance turns on? That sudden energy draw can cause a momentary surge to the demanding circuit and affect all connected outlets. In North America, anything above the standard voltage of 120V is considered excess. Smaller surges can happen anytime without signs or warning, yet still surpass a product’s normal operating voltage.

What to Look For

Surge protectors come in a variety of shapes and sizes. Some attach directly to the wall and work like a surge protector outlet. Most others are equipped with a cable that can be anywhere between one to 12 feet in length. When choosing the right surge protector, you’ll want to make sure it has:

  • Outlets for all of your electronics.
  • Spacing to fit power bricks.
  • Long enough cable.

You won’t be doing yourself any favors by purchasing a six-outlet surge protector when you have 10 devices to plug in. The last thing you want to do is daisy chain another surge protector or power strip to make up the difference. That increases the risk of overloading the electrical circuit and it voids the warranty. If you’re uncertain as to the exact number of outlets you need, it's better to overestimate rather than underestimate.

Not all surge protectors are designed with power bricks in mind. Some power bricks are so bulky that they can block a free outlet (or two or three) when plugged in. Even if your current equipment uses standard two-prong plugs, it’s worth choosing a surge protector that has some outlets spaced apart. You’ll still be able to use them all now, yet retain the flexibility to handle any power bricks in the future.

A surge protector won’t do much good if it can’t reach the closest wall socket. Sure, you could use an extension cord, but doing so doesn’t guarantee full protection and often voids the product warranty. So when in doubt, choose surge protectors with the longest length power cable.

Performance Ratings to Consider

Product packaging is designed to attract attention while conveying information. This can seem confusing, what with all the specs and features. Focus on these ones first:

  • Joules (higher is better): The number of joules listed for the surge protector represents the energy absorption rating. Think of it like a shield that blocks excess energy. Higher numbers mean the surge protector can sustain more (or bigger) hits through single or multiple events before wearing out. So if a surge protector has 500 joules of protection, it could theoretically handle ten 50-joule hits, or four 125-joule hits, or two 250-joule hits, or one 500-joule hit. Small electronics (like lamps, radios, and battery chargers) are fine with joule ratings under 1000. But for computer or home theater equipment, you’ll definitely want to consider surge protectors with joule ratings of 2500 or more.
  • Clamping Voltage (lower is better): The clamping voltage—sometimes referred to as the Voltage Protection Rating (VPR) or Suppressed Voltage Rating (SVR)—indicates when the surge protector will activate to divert excess voltage to ground. While the protection offered by joules sounds good, it’s the clamping voltage (maximum voltage to be allowed through) that ends up being more effective. Lower numbers mean the surge protector is less tolerant of excess voltage. So when comparing a surge protector with 330 V clamping voltage (best option) versus one with 500 V clamping voltage, the latter will allow a higher surge or spike to occur (which can damage components) before doing anything about it.
  • Response Time (lower is better): The response time (typically measured in nanoseconds) indicates how quickly a surge protector will react in order to divert excess voltage. While electronics seem to work instantly, they actually require time to operate. Response time goes hand-in-hand with the clamping voltage. Surge protectors with lower response times activate faster in order to redirect excess voltage before it has a chance to cause damage. If you want the best, choose ones with response times of one nanosecond (or less).
  • UL 1449 (must have): The Underwriters Laboratories UL 1449 is the recognized safety standard that applies to every Surge Protective Device (SPD). This standard lists the certification criteria, design requirements, and product performance testing that manufacturers need to meet in order for a surge protector to be considered safe for consumer use. If a surge protector doesn’t have this displayed somewhere on the box, it may not be a good choice for protecting your equipment.

Extra Features

Many surge protectors offer an array of extra features. While nice to have, they can also bump the purchase price. More expensive doesn’t automatically mean better. Focus on needs first and make sure you don’t overlook the aforementioned performance ratings. It’s up to each buyer to decide whether or not these extras are useful:

  • USB ports
  • LED displays
  • Ethernet, coaxial, and/or telephone jacks
  • 3-line (or all-mode) protection
  • Built-in circuit breaker
  • EMI/RFI filtering and/or power conditioning
  • Uninterruptible Power Supply (UPS) battery backup
  • Replacement (or protection status) indicator lights and/or audible alarms
  • Energy-saving (e.g. primary plugs, timers, etc.)
  • Wireless remote control
  • Motion sensors
  • Whole house surge protection

Warranty

As with most consumer electronics, surge protectors come with a manufacturer’s warranty that covers connected equipment up to a specified maximum dollar amount (which varies from product to product). Hopefully, you’ll never have to use it, but it’s always best to be prepared. Make sure you thoroughly read the fine print regarding the warranty coverage. Some claims require the surge protector, all the equipment connected to the surge protector (even if it wasn't damaged), and original receipts to be honored.

There’s usually a lot of exclusions, conditions, and limitations that need to be met before you’d see a dime, and full reimbursements are never guaranteed. You can also expect claims to take three or more months to process.

Remember:

  • It’s critical to plug a surge protector into a properly grounded wall outlet. Using a three-to-two prong adapter does not count. Otherwise, it won’t be able to protect from surges like it’s meant to.
  • Joules aren’t everything. Be sure to equally consider both the clamping voltage and response time.
  • Don’t daisy chain surge protectors with other surge protectors, power strips, or UPSs for more outlets. You run the risk of overloading your home's electrical circuits, igniting an electrical fire, or voiding the surge protector’s warranty.
  • Surge protectors gradually wear out over time and won’t always indicate when a replacement is needed. There’s no set rule, except that it’s a good idea to buy new surge protectors after the old ones have done their job (i.e. if there have been serious power fluctuations, blown transformers, or lightning strikes in your area.)