Two important factors have come about in relationship to electrical power quality. Generally speaking, the quality of electrical power delivered to the home has either remained the same or in most cases has become worse. The other factor is the rapid advance and wide spread use of digital technology in nearly everything we touch in the home, a digital technology which is faster than ever before. High speed digital and/or lower quality power cause many problems ranging from unexplained home automation reliability issues to catastrophic appliance failures. In the world of electrical power there are two primary issues: power quality and power reliability. The focus here is quality since this is a problem which is considerably more frequent, typically changing by the hour.

A centralized approach to electrical power quality is one commercial and industrial facility engineers have implemented over the past few years and is now finding its way into “whole house” residential applications. Many try to address power quality problems with commonly known devices called surge suppressors, officially named “Transient Voltage Surge Suppressor” or “TVSS”, more knowledgeable people know it’s a centralized “Surge Arrester” they need (also an official name) but there’s more to it than just the official name as you will see below.

The entire electrical power surge equipment arena is confusing and in some cases end users have become down right skeptical about the effectiveness of these devices and for good reason. The confusion and skepticism comes from manufacturers’ claims, mixed with a few facts and little or no information on, independent, third party certifications (Underwriters Laboratory) for each model offered. The following is a simple solution to this wide spread confusion, a method to separate fact from fiction; here are the steps:

1.) First, per the National Electrical Code “a TVSS shall be a listed device” (NEC Article 285.5) meaning it must be Underwriters Laboratory (UL) Listed to be installed under the electrical code; this is mainly for safety reasons. The listing requirement eliminates about a third of the products offered on the market as electrical power surge equipment. Yes, believe it or not there are quite a number of devices with no UL listing / certification of any kind, so do yourself a favor and confirm that a device you’re considering has the official UL mark.

2.) Next, for the two thirds or so devices left over, check for the type of UL Listing category or better yet, look for the UL Listing file number and get the product’s Listing on UL’s web site. There are two general categories, for electrical power service surge applications, for which a particular device is UL Listed. The categories are: UL1449 “Transient Voltage Surge Suppressor” (a.k.a. TVSS, surge suppressor: code XUHT) or ANSI / IEEE C62.11 UL “Surge Arrester” (code OWHX).

Under the more common “surge suppressor” listing there are a couple hundred manufacturers selling thousands of products; products range from simple plug in power strips to the most sophisticated looking, permanently wired, modular suppressor systems you’ve ever seen. Devices with a “Transient Voltage Surge Suppressor” UL1449 listing (including those with IEEE C62.41 test score) have never been evaluated by UL as to the effect of the suppressor on connected loads or the adequacy of the suppression level to protect connected equipment from damage due to transient voltage surges. Of course UL has tested them to be certain of their safety (e.g. fire hazard, shock, etc.) but not to see if they protect your equipment or improve power quality.

On the other hand a Surge Arrester marked with UL and with ANSI / IEEE C62.11 is equipment which has been tested to afford protection against surge-related damage to secondary distribution wiring systems and/or to equipment connected thereto. The few models with this listing have been tested to see that they meet or exceed their published performance specifications which include passing the ANSI / IEEE C62.11 spec and, in a catastrophic failure mode, render themselves safe.

3.) Third, since the goal is to install a device that actually has been third party (UL) certified to protect wiring and connected equipment, the “surge suppressors” in step two would be eliminated. In reality there are a small number of specialized manufacturers who produce ANSI / IEEE C62.11 UL Listed Surge Arresters.

4.) Finally, compare the performance specs of the Arrester Listed models. Look at the Maximum Continuous Operating Voltage or “MCOV” and the initial clamping voltage. The higher the MCOV figure and the lower the initial clamping voltage the better, this is a good indication of quality in design and construction.

These steps will provide any buyer with fact based qualifiers in considering electrical power protection / power quality equipment. Actually UL Listed Surge Arresters are the equipment most people believe they are receiving when a “surge suppressor” (TVSS) device is installed but later become skeptical when it fails to improve power quality or protect their home and equipment.

Eventually there will be additional questions related to: maintenance, installation, electrical service size, components, application, etc. and here is where a call to the manufacturer or dealer of the Surge Arrester may be required.

Always keep in mind that in order to have quality low voltage (home automation, home theater, etc.) you must first have quality high voltage.

Ramon Esparolini is Vice President of RayMark Engineering an exclusive marketer and consultant of power quality devices for commercial, industrial and residential applications. Formerly Ramon Esparolini was Managing Director of USA operations for Klotz Digital, the worldwide leader in fiber optically based digital audio control, distribution, processing, and routing for the radio broadcast studio/control room industry. For more information contact Ramon Esparolini at RayMark Engineering in Atlanta at 770-281-8821.