Tripp Lite
1111 W. 35th Street
Chicago, IL 60609
+1 (773) 869-1774
+1 (773) 869-1329

Surge Protector Buying Guide

Protect computers and electronics from damaging power surges.

What is an electrical surge?

An electrical surge, or power surge, is an intense, short-duration voltage increase that travels through electrical wiring or other cables that transmit data or energy, such as phone lines and coaxial cables for TV reception. Common causes of surges include:

  • Lightning strikes
  • Power outages and downed power lines
  • Tripped circuit breakers
  • On/off cycles of large appliances and tools
  • Accidents and malfunctions at the power company or on the electrical grid

What is a Surge Protector?

A surge protector is designed to protect any device with a standard AC plug from damaging power surges and disruptive line noise transferred through the electrical wall outlet. A surge protector may have a long power cord or it may plug directly into the wall, and it usually has multiple outlets for connecting equipment. Some surge protectors also include protection for phone/modem lines, network (Ethernet) connections, and coaxial connections for cable, antenna, or satellite TV reception.

ISOBAR6ULTRA surge protector

Be careful not to confuse a surge protector with a power strip. They look very similar, but a power strip provides only an extension cord and additional outlets, with no protection against surges and line noise.

What equipment needs surge protection?

Any device that plugs into an AC outlet can benefit from a surge protector. The most vulnerable pieces of equipment are those with memory and sensitive electronic circuitry. A surge protector is essential for:

Surge protector environment
  • PCs and computer peripherals such as printers, monitors, and routers
  • TVs, DVRs, cable boxes, satellite receivers, sound systems, and other home theater components
  • Video game systems
  • Lighting, tools, small appliances, and office equipment

Note: If you need to protect a computer, consider an uninterruptible power supply (UPS), which provides surge protection and battery backup to keep the computer on during an outage.

How does a Surge Protector work?

When the voltage rises above the accepted level, the surge protector suppresses the excess voltage to prevent it from causing harm. Specifically, internal components called metal oxide varistors (MOVs) absorb the excess voltage and divert it to the ground wire, preventing it from reaching the connected equipment. To function effectively, a surge protector must be connected to a properly wired and grounded AC outlet. Some surge protectors include LEDs that alert users to possible wiring problems.

What are joules?

A surge protector's joule rating indicates how much energy it can absorb before it fails. The higher the number, the greater the protection provided. The type and value of the equipment to be protected are key factors in determining the amount of protection needed. Are you protecting a $500 PC or a $10,000 home theater? Obviously, the higher the value, the higher the level of protection required. If you're located in an area with frequent thunderstorms, also consider a higher level of protection.

When selecting a Surge Protector, there are a few questions that need to be answered.

How many outlets do you need?

Determine how many items you will be plugging into your surge suppressor, and purchase one with at least as many outlets as you expect to need. Remember that transformer plugs are wider than standard plugs. Many surge protectors are designed to accommodate transformer plugs without blocking adjacent outlets.

What level of protection meets your needs?

As previously mentioned, a surge protector's joule rating tells you how much energy the surge protector can absorb before it fails. A higher number indicates greater protection.

What kind of equipment will you be plugging into your Surge Protector?

Home electronics, computers, office equipment and workbench tools have different protection needs. Be sure to choose a surge protector that protects your equipment on all inputs, including telephone lines (RJ11), computer network (RJ45), and cable jacks (coaxial).

Other Considerations

  • Eco-friendly Solutions

    Look for a "green" surge protector with special circuitry that reduces energy consumption and lowers your utility bills.

  • Environment

    Will the surge protector be used in an environment where it could get damaged? Some surge protectors are made with all-metal housings which are virtually indestructible.

  • Cord Length & Plug Design

    Determine how far you will place your surge protector from your grounded AC outlet, and select a surge protector with a cord at least that long. If you want to place furniture flush against the wall in front of the AC outlet, choose a surge suppressor with a right-angle plug.

  • Indicator Lights

    Most surge protectors include diagnostic LEDs that confirm power availability and protection status. After repeated power surges, the protective circuitry will burn out so it's important to know whether or not your surge protection is still functioning.

  • Form Factor

    Surge protectors come in multiple styles and sizes, including strip, in-line (for use with laptops), direct plug-in and under-monitor, among others.

  • Connected Equipment Insurance

    In the unlikely event that a surge protector fails, this insurance covers replacement costs for any connected equipment damaged by a power anomaly. Make sure that the insurance amount is enough to cover all of your connected equipment.

Ready to purchase?

Choose from a wide selection of Surge Protectors for home, office, IT, industrial and medical environments.

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Tripp Lite
1111 West 35th Street
Chicago, Illinois 60609
United States

+1 (773) 869-1111 Main
1 773.869.1329 Fax

Business Hours
8 AM - 5:30 PM CST

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Need help with your purchase?
We're always available to help with questions, including product selection, sizing, installation and product customization. Call us at +1 (773) 869-1774 or email