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Lightning builds plasma wires that can short high energy,
utility power through other copper wires. Lightning simply creates the short circuit. Then a higher source of energy - AC electric utility - follows to vaporize those copper wires. That point was described by Colin Baliss: Although lightning strikes have impressive voltage and current values (typically hundreds to thousands of kV and 10-100 kA) the energy content of the discharge is relatively low and most of the damage to power plant is caused by 'power follow-through current'. The lightning simply provides a suitable ionized discharge path. Yes direct strikes have caused damage. This was a problem in the early days of ESS-1 - the first electronic switching computers for telephone systems. And so engineers then reevaluated the earthing system in those few 'problem' Central Office buildings to correct the reason for electronic damage - human failure. Described above is not a best solution. But then a best solution is typically not required. Above described system will not avoid damage from every possible direct strike. But then many of these 'rare' direct strikes have never been experienced by many - maybe most - people. For example, something called hot lightning may discharge the entire cloud in one single strike. It has been observed - just like tornados have been observed (most people also will never witness a tornado in their lifetime). Defined here is effective protection for most direct lightning strikes. It costs so little. To enhance same for the other maybe 1%, serious facilities such as 911 systems, cell phone towers, telephone switch stations, and nuclear hardened maritime facilities spend far more than a few $10. They spend $thousands more on earthing alone just to also protect from the last 1% of worst case lightning strikes. I cite nuclear hardened facility especially since a 1998 IEEE paper described a Norwegian maritime station damaged by a lightning strike. They discovered major installation faults in the earthing system for what was suppose to be a nuclear EMP protected station. Faults that even permitted lightning to cause damage. Again, failure directly traceable to a human. Major construction required to repair a simple earthing flaw. Homes contain superior earthing systems that we still don't use today. Ufer grounds could have been installed using existing structure - if planned for when footing were poured. But we still don't install superior earthing systems in new homes 30 years after the transistor existed. Costs to use that Ufer ground on existing homes are now extreme because Ufer grounding was not enabled when house construction started. OP must make do with simple earth ground rods. Properly installed, the Original Poster is quite unlikely to suffer any damage from direct lightning strikes. For but a few $10, he gets a massive increase in direct lightning strike protection. Not perfect. Just a massive improvement. Randy wrote: So, you claim that ALL lightning strikes can be safely shunted to Earth, with no damage along the path? Well, I don't have 30 years experience in the electrical transmission and distribution industry, but I do have 25 years. And I have seen properly earth grounded transmission and distribution poles where the awg #6-#4 CU wires were mostly vaporized. Sure, there were bits and short pieces left, but for the most part, the wire was gone. I confer with you most of what you say, but you would be not completely honest to say that all lightning strikes can be earthed with no damage. Possible? Maybe. Practical? Nope.There will be strikes of magnitude where practical techniques fail. |
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