Yep - near solid blocks of part carbonised, plastic with metal traces throughout them.
Luckily, the comms front end systems/facilities were a fair distance from the data storage farm and - it doesn't need to be an almost direct strike - anywhere near those nicely shielded cables and they'll conduct the surge (sufficiently to upset most modern 'digital' electronics systems) for a mile or more You really need to have a good earthing facility and (vague memories of ) about a 4" gap - or optical fibres to be reasonably hopeful of surviving a near strike. Oh - and check for metal conduits/tubing for power, lighting, alarm systems, fire suppressant gas distribution systems, water supplies to sprinklers, and the telephone system including backup modem connections. Although, If I remember my physics correctly, most terrestrial lightning strikes are actually travelling up from the ground. And from a course I attended on telecommunications systems - a 'senior military person' complained that there were nothing to stop a lightning strike blowing up several hundred modems in the communications centre he managed - The lecturer responded that the company did fit appropriate devices to the lines - At the end where they entered the exchange! (Not even a considered, and limited military response to that.) Basically - for most organisations I'd say that it's probably better to have excellent earthing facilities, get a good insurance policy with a reasonable company, and maintain adequate backups to setup replacement systems is probably the answer, rather than spending lots on trying to avoid the effects of a lightning strike. and - if you have lots of lines coming into a processing centre, don't have them all coming in through the same access points, and frame/relay locations/systems Wanna guess what proportion of major office blocks have all the comms lines coming through the same hole in the wall/foundations Designed for purpose! Perhaps I shouldn't mention the London Flood Control centre that was in a basement of a building at the end of a bridge over the river Thames - It got flooded out (well filled in) by a burst water main! JimB ----- Original Message ----- From: "Andy Medina" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, August 20, 2006 7:13 PM Subject: Re: Surge protecting 10/100 Base-T cable modem connection > On Sun, 20 Aug 2006, James Button wrote: > > > While I don't know of any particular device, > > I worked for a company who had 'optical relays' installed for their digital comms lines - shame it didn't work when they got a lightning strike ! > > NOTHING works with a (almost) direct lightning strike ! Those million volts have been traveling through miles of air. It will jump across the small gap (including the "isolated" optical gap) created when the protection device blows. Actually it will probably fuse [no pun intended :) ] the device into "one solid mass". > > > However, I'd have thought that for simple surge protection, you'd be looking at any simple plug-in mains socket, rather > > than needing something for the actual digital communications cable > > Communication lines should be protected *before* they enter any device since these lines can also carry voltage surges from lighting strikes some distance away. Cable/DSL/phone lines should have surge protection devices before entering any Cable/DSL/analog modem. ---------------------------------------- > WIN-HOME Archives: http://PEACH.EASE.LSOFT.COM/archives/WIN-HOME.html > Contact the List Owner about anything: [EMAIL PROTECTED] > Official Win-Home List Members Profiles Page > http://www.besteffort.com/winhome/Profiles.html -- ---------------------------------------- WIN-HOME Archives: http://PEACH.EASE.LSOFT.COM/archives/WIN-HOME.html Contact the List Owner about anything: [EMAIL PROTECTED] Official Win-Home List Members Profiles Page http://www.besteffort.com/winhome/Profiles.html
