Log In Sign Up

Tech Reference: Surge Protection for Office Equipment

Contrary to popular belief, the main purpose of surge protection is not to protect electronic equipment against lightning strikes. While most surge protectors will protect office equipment from these enormous — but rare — power surges, today’s more sophisticated surge protectors are primarily designed to protect office equipment from smaller, much more frequent electrical disturbances. 

Today’s copiers, printers, facsimile machines, and other office equipment utilize much more advanced, sensitive electronic circuitry than the older-generation machines that preceded them. This circuitry can process large amounts of data at great speeds; however, it is also capable of detecting small electrical disturbances within an office’s power supply, and misinterpreting them as legitimate communication signals. These small electrical disturbances are typically caused by: (1) sudden surges in voltage as electrical devices (such as refrigerators and air conditioners) turn on and off; and/or (2) slight voltage fluctuations in the power supplied by the local electrical company.

The most common and potentially damaging of these small electrical disturbances are spikes. Spikes are very short, sudden bursts of higher-than-normal voltage. The larger the spike, the greater the potential for immediate damage. However, even the smallest spikes can cause machine data errors and other problems, and their cumulative effects may ultimately result in premature office equipment failure.

Surge protectors have become increasingly sophisticated while remaining affordable, and will adequately protect office equipment from both large and small electrical disturbances — including spikes. These devices work by offering a “path of least resistance” to channel excess voltage away from office equipment circuitry; this helps to maximize the longevity of valuable office equipment by “shaving” excess voltage, ensuring only the proper amount of power gets through to these machines.

The most basic surge protectors operate much like circuit breakers, reacting to extreme power surges or spikes by channeling excess voltage to a fuse (and typically incorporating a light to indicate the fuse has been “blown”). Since these surge protectors require replacement after each exposure to excessive voltage, many manufacturers offer free lifetime replacement warranties for them. However, most of these basic surge protectors will protect office equipment from relatively large electrical surges only, and may not adequately protect office equipment from smaller, more frequent electrical disturbances that can have harmful long-term effects.

Many of the more sophisticated surge protectors utilize metal oxide varistors (MOVs) to rechannel excess voltage, while also incorporating circuit breakers to protect against sustained overvoltages. An MOV is made from a material that is highly resistant to electricity up to a certain level of voltage. Therefore, when used in a surge protector, an MOV is designed so that it has no effect on an AC power line receiving “normal” levels of voltage; however, when voltage exceeds a certain threshold, the MOV’s resistance drops immediately, offering a path of least resistance for the excess voltage. Surge protectors incorporating MOVs are designed with relatively tight electrical tolerances, and will typically protect office equipment from both large and small electrical disturbances.

Most of these more sophisticated surge protectors also incorporate filtration devices for electromechanical interference (EMI) and radio frequency interference (RFI), which occur when other electrical sources (such as fluorescent lighting, nearby radio stations, or even the engines of passing automobiles) send out electrical energy that can be absorbed by an office’s electrical wiring, or directly by office equipment itself. If exposed to EMI and/or RFI for extended periods of time, the electronic circuitry of a copier, printer, facsimile machine, or other electronic device can be adversely affected.

Perhaps the most important feature of a surge protector is the manufacturer’s connected-equipment warranty that stands behind the product’s performance. A connected-equipment warranty states that if any equipment is damaged while a particular surge protector is in use, the manufacturer of that surge protector will compensate the end-user for a specified amount of the damages. These warranties range in value from a few thousand to several million dollars, depending on the manufacturer and the sophistication of the individual surge protector. As a result, many end-users perceive surge protectors with connected-equipment warranties as “insurance policies” — that is, they know their office equipment is fully covered, even if the surge protectors fail to do their job.