Daily Archives: October 9, 2009

Do you have structures with lightning protection?  Is it properly installed?  How can you tell?  While conducting a recent mock VPP audit, IESO discovered that a lightning protection system being installed did not comply with NFPA 780, the Standard for the Installation of Lightning Protection Systems.

Down-conductors were exposed inside the structure and improperly bonded to surrounding ground systems, which could have caused a sideflash during a strike.  Anchor points were set in mortar joints,

rather than brick and concrete, and numerous down-conductors had bends of 90 degrees in less than the required 8-inch span.  These “tight” bends greatly reduce carrying efficiency and increase the risk of sideflash as the bolt attempts to “find the path of least resistance.”  Imagine the system doing exactly what it should do by capturing a strike, then routing several hundred million volts and 20,000 amps INSIDE your facility fully exposed to employees, equipment and raw and finished materials, in this case flammable liquids!