Xref: utzoo sci.electronics:13127 sci.physics:13777 Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!pt.cs.cmu.edu!andrew.cmu.edu!kr0u+ From: kr0u+@andrew.cmu.edu (Kevin William Ryan) Newsgroups: sci.electronics,sci.physics Subject: Re: St Elmo's Fire (was Re: Lightning) Message-ID: Date: 26 Jul 90 16:03:50 GMT References: <1990Jul18.111525.5749@ioe.lon.ac.uk> <2436@speedy.mcnc.org> <1990Jul19.210925.165@mlb.semi.harris.com> <1047@tsdiag.ccur.com>, <3984@healey> Organization: Biology, Carnegie Mellon, Pittsburgh, PA Lines: 24 In-Reply-To: <3984@healey> Heard a nasty lightning story some time back, thought folks might find it interesting. A friend of mine had a bunch of Hewlett Packard (sp?) equipment set up. The equipment was connected by a 'daisy chain' arrangement, which made a loop connecting the various modules. Due to space requirements they had the equipment set up on a table around a pillar, so that the daisy chain circled the pillar itself. What they didn't know was that the ground wire for a lightning rod ran down inside the pillar. There was, of course, a storm. When the lightning struck the rod the equipment all but exploded. Smoke, cracked boards, warped containers, melted wires, fused components, the works. Imagine the induced voltage in a circular conductor roughly four feet in diameter around a conductor carrying up to 30,000 amps... Needless to say the equipment was a _total_ loss. kwr Internet: kr0u+@andrew.cmu.edu