Southeastern fast food chain solves chronic "dirty" power problems and saves thousands of dollars with installation of new power conditioniing units.

In this industry, we define "dirty" power as any unwanted noise, spike, surge, or sag that can eventually disable electronic components if you leave them unprotected. Dirty power comes in two varieties: external, high-voltage spikes from utility and telephone companies; and low-voltage electrical bursts from excessive signal noise or machinery inside a building.

As microprocessors, memory chips, and other computer-controlled components become more prevalent in business, it's only a matter of time before dirty power preys on these unwary devices. And since these tiny components usually require less than a volt and an amp to operate, even the smallest spike can disrupt or damage them.

Bojangles Restaurants Inc., Charlotte, N.C., knows this scenario all too well. Until recently, it was an unknowing victim of such dirty power problems. In fact, this fast food chain's power problems totaled thousands of dollars each year.

How did it all begin? When low-voltage spikes struck, employees couldn't send important data in the store's administrative computer system by modem to corporate headquarters via its wide area network (WAN). However, they needed this data to manage supply ordering, inventory, cost accounting, administration, banking, and e-mail. But like so many computer users, the chain believed the $10 surge protector strip it purchased at the local discount store was enough to stop high-voltage power surges and in-house, low-voltage spikes. Unfortunately, they were wrong.

In 1998, Bojangles spent about $35,000 at its Aiken branch alone for parts and labor to repair chips and boards in cash registers, office computers, and radio-controlled headsets damaged by low-voltage spikes and noise generated inside the building.

"The Aiken store's electrical system was a nightmare for everyone involved due to constant troubleshooting and repairs," says James Dean, director of construction for Bojangles. "No matter what we tried to do, the dirty power just kept blowing out components in the computer system. Power spikes would wipeout everything on the hard drives, burn up modems and keyboards, and fry motherboards."

Since store managers in Aiken began calling the corporate office for help so often, Dean sent Information System technicians every week to search for answers. They even monitored power coming into the building for several months, but never detected a surge or spike from the power company.

After investigating, technicians discovered the dirty power was from internal low-voltage spikes and other internal circuit noise. They determined at least sixsolenoids were operating on various machines; from refrigeration units to exhaust fans. Needless to say, an abundance of dirty internal power was inevitable. The fact that starter relays, capacitors, and transformers all fed into the same circuit breaker panel on the same grounding lug only compounded the problem. Worse yet, the computer systems connected into the same panel box. As noise and spikes cycled into the breaker box from machinery all over the building, the computer's low-voltage components took hits that froze up PC screens or melted down circuitry.

Realizing the dirty power originated internally, Dean turned to W.A. Brown, Salisbury, N.C., for help. W.A. Brown recommended the Brown Guard Power Quality product family. Ideally suited for retrofitting, the Brown Guard Power Manager 25-APC (a 25A power conditioning unit) provides clean power by using a low impedance isolation transformer, surge diversion, and electrical filtering. It's available with one main breaker circuit and 11 branch circuit breakers with an isolated ground bar. The ground bar is the termination point for all equipment grounding conductors wired from dedicated isolated ground receptacles.

Bojangles technicians installed two 4A Brown Guard Power Isolation Modules to access 6.5A of clean power for the store's PCs and related equipment. The protection devices plug into existing receptacles, and the critical electronic equipment plugs into the power isolation modules. Therefore, all power must pass through the guards before they route to the computer system.

"The protection units were easy to install. Within a few hours they were all mounted, wired, and the equipment was hooked up. The units have eliminated the potential for dirty power problems in our existing stores and worked trouble-free in 10 new stores," explains Dean. "The Power Isolation Modules we installed eliminated all our internal, low-voltage spike problems. We've been using our computer systems for a little over a year now with no dirty power problems"