Power Protection in the Home Theater - Use of Surge Suppressors to Guard Expensive Electronic Gear

Surge Suppressors - A First Line of Defense

All Home theater equipment should be equipped with at least some form of surge protection. Surge suppressors represent the most basic form of power protection - a first line of defense for all sensitive electronic gear.

Keep in mind that a surge in the ac voltage or a lightning strike, could lead to disaster - turning expensive gear into a smoking heap of plastic and metal. Investing in a suitably rated surge protector is surely a lot cheaper than having to replace expensive Home entertainment electronics.

The large selection of suppressors available on the market at an even wider range of price levels can make the process of selecting an appropriate protection device far from simple. Many of these surge suppressors would look the same to a non-technical person - with almost nothing that distinguish the cheapest from the best.

In their simplest form, surge suppressors often come as an inexpensive surge protected multiple-outlet power-strip. More expensive units would normally incorporate additional surge protected connections for the phone line and the coax TV input; some units include surge protected LAN connections as well. In this manner, anything that interconnects with your equipment would have to go first through the surge protection circuitry within the power-strip.

How Surge Suppressors Work

The basic operational principle behind surge suppressors is to clamp high transient voltages while absorbing this potentially destructive energy. This energy is then dissipated in the form of heat - thus protecting vulnerable circuit components and preventing system damage.

In the event that the surge lasts for several milliseconds, the process may also cause enough current to trip the house circuit breaker, or blow the equipment fuse, thus protecting your gear.

Surge suppressors usually make use of a mix of components to suppress voltage spikes on the line. However, the mostly used component in surge protection circuitry is the Metal Oxide Varistor (or MOV).

The MOV is not the only surge protection component - gas-tube surge arrestors, avalanche diodes (similar to power zener diodes), and reactive type passive circuitry using inductors and capacitors, all possess the desired electrical properties required to dampen a transient behavior.

None of these devices does represent the perfect surge suppressor. Some lack speed, while others - like avalanche diodes - though extremely fast acting, do have a limited energy absorption capacity. For this reason, commercial surge protection devices combine several of these technologies arranged in multiple stages, to prolong surge suppressor life and improve response times.

Surge Suppressor Ratings

This discussion will not be complete without highlighting a few of the most basic parameters that define the capabilities of a surge suppressor; these are the UL listing, voltage rating, peak surge current, and power handling.

IEEE 1449 Underwriters Laboratories Listing: Referred to as 'UL 1449' or simply 'UL listing', represent a set of specifications that determine if a surge suppressor is safe during use.

Ensure that the selected surge suppressor is labeled as 'UL-listed transient voltage surge suppressor (TVSS) 2nd edition'. A UL-listing as 'power tap' is not sufficient.

A UL-listed TVSS does not imply that it will protect your equipment from surges, but rather that the surge protector is not likely to pose any personal hazard to you during use e.g. through electrocution, fire, etc.

Operating Voltage: The lower the voltage rating of a surge suppressor, the more effective protection the surge suppressor will provide, however the voltage rating has to be in line with the respective application. In particular, the chosen suppressor voltage rating should allow the normal peak AC voltage to exist across the line - this is 1.414 times higher than the specified RMS value.

Peak Surge Current: This represents the maximum transient current that the suppressor can handle during a surge.

Joule Rating: Also referred to as 'Energy rating', this is a measurement of the energy absorption capability of the surge protection device. Typical values may vary from 500 to 3000 and over. The higher the joule rating, the better is the surge suppressor capability to absorb energy spikes on the line.

A Word of Caution

Designed properly, surge suppression devices can work over-and-over again, but...

Do not take surge suppression devices fo