Surge protection’s role in equipment reliability

Ed Doherty
Tags: maintenance and reliability

When discussing reliability, we are really talking about uptime. How do you maximize uptime? It’s a complete and thorough process that requires every possibility to be covered and addressed. Power quality is critical enough that a plan is usually created and issues addressed. For power loss, it usually means the installation of a UPS, generator or both. Also, surge suppression on the AC power side is a common part of the uptime plan.

There are two areas that are frequently overlooked in the power quality uptime plan. The first is lack of lightning protection, and the second is data line protection.

Lightning can cause a massive amount of energy to enter your facility. This energy must be diverted away from your critical equipment. The protection should be in front of all equipment, including your generator or UPS. The biggest mistake is employing metal oxide varistors (MOV)-based surge suppression too early in the power path. Spark gap technology diverts the energy without degrading. After the spark gap protection, the MOV works well to reduce the voltage to safe levels. Surge suppression is designed to sacrifice to protect the downstream equipment, so it should be modular and hot-swappable if protection is compromised. It can then easily be replaced without causing downtime while it’s being repaired.

The second area is the signal or communication cabling. If you only have surge protection on your AC power side, then you are leaving a backdoor path for surges to enter your equipment and cause damage. A complete surge protection strategy requires addressing surges on all connections to your equipment. A surge can travel on any wire, power or communication. It is important to investigate all signal lines such as coaxial, Ethernet, RS-232, etc. These represent paths that need protection.

Even if you do not live in a lightning-prone area, surge suppression is needed. A simple way to think of surges is to place them into two classes, external and internal. Most people are familiar with external surges, lightning being the most common. Internally generated surges are independent of weather. Internal surges can be created during normal operation, or when equipment inside the facility is turned on or off. Without going into complete detail, these internally generated surges can appear on your power, communication or signal cabling.

Increasing equipment reliability requires attention to detail. The easiest way is to review a wiring schematic of your equipment, then draw a line around it. Any path you cross needs protection. Lightning protection and data line surge protection are small but critical parts of a complete reliability plan.

About the author

Ed Doherty is the product marketing manager for Phoenix Contact’s Trabtech product line. To learn more, visit www.phoenixcontact.com.

About the Author