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Lightning Strikes Twice: Proper Grounding Prevents Outages
A Total Systems Approach to Electrical Grounding May Save Millions of Dollars
Lightning storms occur on average 130 days a year in Florida’s “Lightning Alley,” making this area one of the most dangerous in the United States with respect to weather- related incidents.
It is not true that lightning never strikes the same place twice. Communications towers in this area are prone to being hit during any major thunderstorm. If not properly equipped, this regular lightning activity can cause millions of dollars in damage.
Orange County, Florida, is in the heart of the Alley, and it sees more than its fair share of damaged buildings, disrupted power lines, fires and, unfortunately, injuries caused by lightning strikes.
As the former supervisor of radio services at Orange County's Public Safety Communications Division, Tom Sorely was responsible for keeping its 820,000 residents safe. It was his job to make sure that the communications lines remained open 24-7, however this task wasn't always easy when overseeing 9 tower sites and 10 emergency response centers in the county.
"We're in the most lightning-prone area of the country," Sorely said. "Our antennas are at the top of 300-ft lightning rods!”
Sorley explained that one or two strikes per month on a large tower were routine between the months of May and October.
“They don't all do damage. But we have lost our entire network at times and every public service agency is in jeopardy when that happens,” he said. "Lightning strikes can be costly!”
Over the last 10 years, lighting strikes have caused nearly $2 million in damages to transmitters and other lost equipment.
David Brender, National Program Manager for the Copper Development Association’s Electrical Program, urges all building owners and facility managers to check their electrical grounding systems and to take a “total systems approach” when evaluating lightning protection.
“A well-placed lightning strike can seriously compromise any facility, leaving lost equipment and damaged electronics in its wake,” said Brender. “Lightning protection systems that benefit from the inherent conductive properties of copper may give buildings the best chance to avoid this unpredictable damage.”
In essence, lightning protection is the process of creating electrical paths of least resistance in order to direct strikes to the ground and away from where they can cause damage.
Sorley explained that the grounding systems at the facilities complied with the electrical codes when they were built, but they were not all designed by the same contractor, which eventually led to problems.
“No single individual or contractor understood grounding as a total system,” said Sorley. “Grounding and its maintenance were just something everyone took for granted. What we now have is a total systems approach to lightning protection."
The “total systems approach” begins with the materials. Copper radials, plates, electrodes, conductors and wiring are all integral to the success of a lightning protection system. Corrosion resistance, reliability and superior conductivity make copper the ideal metal for a robust grounding system.
CDA recommends building and facility managers to take the necessary steps to protect their property from lightning damage. A “total systems approach” with copper grounding will provide the best support for those areas where lightning does strike twice.