In Canada, on average there are 2.4 million of lightning flashes per year with the Foothills and Eastern Slopes of Southern Alberta being amongst the most lightning prone areas in the country with half million strikes every year. According to the U.S. National Oceanic and Atmospheric Administration, lightning happens when the “action of rising and descending air within a thunderstorm separates positive and negative charges. Water and ice particles also affect the distribution of electrical charge. Lightning results from the buildup and discharge of electrical energy between positively and negatively charged areas.” Lightning is often dramatic, exciting and scary all at the same time, and while the risk of being struck exists, the risk to streetlights and floodlights mounted on columns and high masts is exponentially larger.
Dobbyn Electrical Services Ltd. is the only LPI-certified Master Installer/Designer of lightning protection systems in western Canada, and can offer third-party certification of completed systems through the Lightning Protection Institute or Underwriters Laboratories. A professionally installed lightning protection system is the best way to eliminate or minimize lightning damage to a structure. Quality control is crucial, and installation is not a do-it-yourself project. When the lightning protection network is in place, the lightning strike is intercepted and directed to ground without impact to the structure, occupants, or contents.
It is sometimes thought that circuit breakers and fuses can provide overvoltage protection, but they are designed to protect equipment, from an event such as a short circuit or overload – not a lightning strike. There are several ways that an overvoltage can occur and possibly damage the luminaires in streetlights and floodlights.
The most dramatic is a direct strike to the column by lightning.
Potentially much more damaging, is a lightning strike near to the columns. This can cause transient overvoltage’s on both mains power supplies and other data communication, signal or close by telephone lines.
Far less common in terms of damage, surges can also occur on the power grid from switching of heavy electrical loads nearby or the sudden interruption of the supply.
Finally, LEDs can also be damaged by Electro-static discharge, ESD. However, this is a different phenomenon. Unlike the above, these tend not to be transmitted on power or data lines.
In January 2003 the American Meteorological Society issued a Bulletin endorsing lightning protection requirements, stating “It is now well established that properly installed and maintained lightning rod-based protection systems significantly decrease lightning damage.” In 2001 a joint paper was issued by lightning experts at the U.S. Army, Navy, Air Force, Nat’l Severe Storms Laboratory, Defense Explosives Safety Board, Dept of Energy, NASA and FAA, underscoring the critical role that lightning protection systems play in protecting national infrastructure (Source: Lightning-risk.org).
A lightning protection system that meets national safety standards includes the following elements:
Strike termination network (air terminals or lightning rods);
Grounding electrode network;
Equipotential bonding network; and
Surge Protection Devices (SPDs) for all incoming power, data and communication lines, used to protect equipment from events such as extremely short duration high voltage spikes.
Whilst SPDs are common in buildings, they are much less used in exterior applications. This can put streetlights and floodlights at risk. Failure to make proper provisions for special grounding techniques or any of the above five elements can result in inadequate protection. At Dobbyn Electrical Services Ltd., we specialize in street lighting and overhead lighting, industrial wiring, and everything in between, contact Dobbyn Electrical Services Ltd. at 403-236-8877 today for a complete assessment of your Surge Protection needs.