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Michael Terrell cries, "Woe is me. Nothing can prevent
lightning damage." Meanwhile professionals learn from human mistakes and routinely prevent lightning damage: Richard Harrison posts on 7 May 2001 in the newsgroup rec.radio.amateur.antenna entitled "Grounding Question - Connecting to Power Ground": Early in 1949 I started work in broadcasting. I worked in three stations in that year, KPRC, KXYZ, and KTHT. The first two were built in the 1930`s and KTHT was about one year old when I went to work there in 1949. None of these stations ever suffered lightning damage when taking many direct hits during every year. In fact they only dropped from the air for an instant, to extinguish any follow-through arcing when hit, and were returned to the air automatically following an arc kill. In 1949 there were already thousands of AM broadcast stations. Some were improperly protected against lightninmg, but the vast majority, like the stations I worked at, were almost perfectly protected against lightning damage, and so it was almost unheard of. Ben Franklin figured how to protect structures against lightning over 200 years ago. The rest is just elaboration. Or http://www.harvardrepeater.org/news/lightning.html Well I assert, from personal and broadcast experience spanning 30 years, that you can design a system that will handle *direct lightning strikes* on a routine basis. It takes some planning and careful layout, but it's not hard, nor is it overly expensive. At WXIA-TV, my other job, we take direct lightning strikes nearly every time there's a thunderstorm. Our downtime from such strikes is almost non-existant. The last time we went down from a strike, it was due to a strike on the power company's lines knocking *them* out, ... Since my disasterous strike, I've been campaigning vigorously to educate amateurs that you *can* avoid damage from direct strikes. The belief that there's no protection from direct strike damage is *myth*. ... The keys to effective lightning protection are surprisingly simple, and surprisingly less than obvious. Of course you *must* have a single point ground system that eliminates all ground loops. And you must present a low *impedance* path for the energy to go. That's most generally a low *inductance* path rather than just a low ohm DC path. And even from Sun Microsystems "Planning guide for Sun Server room": http://www.sun.com/servers/white-pap...ning-guide.pdf Lightning surges cannot be stopped, but they can be diverted. The plans for the data center should be thoroughly reviewed to identify any paths for surge entry into the data center. Surge arrestors can be designed into the system to help mitigate the potential for lightning damage within the data center. These should divert the power of the surge by providing a path to ground for the surge energy. Did Michael Terrell cite technical facts? Of course not. Others here have posted how damage is routinely avoided. Thank you Michael for your insults. When do you provide a single reason why this well proven science does not work? Its been a few years. When do you provide one good technical reason? Others who learned from lightning damage eliminate a failure rather than just replace electronics. Michael endorses failure as if it was situation normal. Even children are taught not to be quitters. Damage from direct lightning strikes is routinely avoided. So which week was Michael's town without phone service while the telco switching computer was replaced? Oh? They don't disconnect that computer from overhead wires everywhere in town during thunderstorms? How can that be when Michael says protection is not effective? "Michael A. Terrell" wrote: Do you write this drivel every time, or do you copy and past it? Once again, your knowledge of a number of systems is evident. I have seen a lot of damaged telco equipment. In fact, I've been in the Sprint warehouse in Eustis, Florida where they had skids full of lightning damaged circuit boards being sold as scrap. If the wire is never damaged, why do they build their plant with extra pairs? Those pairs are exempt from tariffs, as long as they are only used to replace a damaged pair. I lost my underground phone line when lighting struck an old barn on our property. We had a light out there, so lightning got into our electrical service. Everything critical was on plug in MOV protectors and they all survived. The lightning jumped from the underground power line to Sprint's buried line which they had installed a few inches from the existing buried power line. The pair of wires was vaporized to the street which was over a mile. It wiped out the line card in the pedestal, and the pair back to the CO was damaged. All 16 customers fed by that pair had excessive noise on their phones so they had to switch to one of the spare pairs. That lightning strike did thousands of dollars worth of damage to their equipment, and took weeks to fix. Now, tell us again that Telcos don't suffer lightning damage. |
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