Copper Protects Costly Gear
It was a no-brainer to invest $3,500 in a copper-based grounding system for $1.5-million worth of vital, incomeproducing electronics, especially under the threat of loss of insurance coverage. Not that the owners of Clarion Suites Resort World had any doubts about the need for lightning protection: earlier, an intense strike had ruined the resort hotel's $160,000 phone switch, 60 TVs and 30 microwave ovens.
The resort opened in 1985 and is located near Orlando, Florida, which enjoys the dubious distinction of being the "Lightning Capital of the World." That's why it was initially equipped with lightning protection that presumably met national andlocal building codes. However, over the years the resort had greatly expanded, adding a lot of fragile electronics.
John West, Sr., president of Power & Systems Innovations, Inc. (PSI), Orlando-based power specialists, was brought in to install the new grounding system. His inspection uncovered other common problems, which eventually led to the failure of the existing grounding system. Some of the original connections had corroded because of electrolytic action between dissimilar metals and the ground-levelconnections to the buried ground rods had been damaged by the resort's lawnmowing crews.
Copper's-clad Grounding Rods
To protect the resort's expanded investment in electronics, including a new $500,000 phone switch, PSI installed heavyweight grounding protection: six 50-foot-long, 3/4-inch-diameter, copper-clad steel rods. They were buried upright in a row 12 feet outside the rooms containing the electronics. (The original rods were only 10 feet long and made of galvanized steel; some were glazed as a result of the earlier, devastating strike.)
Only heavy copper cables were used to connect the grounding system to the buried ground rods-no aluminum cables as in the previous system. Most of the joints were exothermally bonded and sharp turns in the grounding cables were avoided. Surge suppressors were also installed.
Low Ground Resistance Achieved
This upgraded system will provide reliable protection because its ground resistance now measures less than five ohms, well below the 25-ohm level recommended by electrical codes; the ground resistance for the earlier system had degenerated to a whopping 105 ohms. The fiveohm resistance also provides superior grounding protection against data-signal errors, according to Mr. West.
To ensure that the resort's electronics are properly grounded, PSI also installed a copper halo ground and a copper ground plate in the room housing them. They are definitely effective, as discovered by Brad Padgett, the resort's director of communications. He had his hand inside a switch cabinet when lightning struck. As he recalls, "I heard the loud crack, saw a spark jump from one panel to the ground plate and smelled ozone from the discharge; but I wasn't hurt and the equipment wasn't damaged."
Since the company that owns Resort World had PSI upgrade the lightning protection at the resort, PSI has installed new copper-based grounding at the corporation's four other facilities in Florida. As a result, none of the others has suffered any lightning damage. Previously, several swimmingpool pump motors, costing $500 apiece, had been destroyed by lightning. Of course, that meant that the pools couldn't be used until new motors were installed.
The history of lightning protection at Resort World proves that it's not enough to install protection that merely meets existing electrical codes and then forget about it. The protection system has to be upgraded as a facility expands, and its effectiveness must be checked regularly to make sure it has not deteriorated. (After protection has been installed, the installer requests a "Master Label" to be issued by Underwriters Laboratory. This label along with the installer's nameplate should be prominently displayed so that, if the building is modified in any substantial way, especially re-roofing, it will be checked by a certified installer, hopefully the one who installed it. This is to make sure that none of the vital protection has been weakened or rendered ineffective.)
Any facility with costly, fragile electronics, such as call centers, broadcast studios, data-processing centers or machine shops with computer controls, requires proper grounding, not just against lightning, but also to prevent spurious signals.
Clarion Suites Resort World: 800/843-8604
Also in this Issue:
- Copper for Faster Chips
- Promoting Efficient Motors
- Copper Protects Costly Gear
- Copper Building Materials Seen by Millions
- Attention Scrap Copper Purchasers
- Bronze Spiders Makes Manhattan Appearance
- Copper is Cool for Motors