The transistor has existed in homes now for 30 years. That means new homes should be built to withstand direct lightning strikes without damage. Such earthing is not difficult. But it requires the builder to plan for the lightning protection 'system' before the footing are poured. It is an old and well proven technology - called Ufer grounds. They are installed in the footing using materials already inside footings. IOW significant and effective protection systems for residential environments need not be expensive. It simply requires planning by the builders - who currently don't consider such 'systems' until much later - when the electrician arrives. Also essential is that all utilities enter as the same location - the service entrance - so that all make a 'less than 10 foot' connection to that single point and most superior earth ground. Ufer grounds, halo grounds, and other simple techniques cost so little when installed during construction. And yet we still build new homes as if the transistor did not exist. Ron Mayer wrote: > Indeed. And yes, a high end data center should survive > a lightning strike (as well as hospital's power systems, etc). > > > Here's a nice article where Suncoast Schools Federal Credit > Union's data center survived a direct lightning strike to > their 480-V service entrance cable. The article spends > a lot of the time talking about the grounding system. > > http://www.ecpzone.com/article/article.jsp?siteSection=12&id=41 > "Starting from the ground up, the main elements of the > [lightning protection] system...include: > > (1) Three 20-ft x 5/8-in (6-m x 16-mm) copper-clad-steel > grounding electrodes [...] The grounding system's resistance > to earth as measured by fall-of-potential testing is 4.3 ohms. > > (2) Another 4/0 copper grounding conductor connects the > ground-neutral bus in the service entrance panel to the > ground bus in a 480-V distribution panel ... > > (3) Multiple uninterruptible power supplies (UPSs).... > > (4) Up to seven layers of voltage surge protection.... > > High Quality Grounding.... "even the most expensive > TVSS you can buy is absolutely useless unless it sees > a high-quality, low-resistance ground. " > " ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly
