On Sun, 16 Dec 2018 12:24:31 -0000, tony sayer wrote:

In article , Kristy Ogilvie
scribeth thus
I once got a bit of grit in my eye that I couldn't dislodge (after DIY
plasterboard work I think), it was damn annoying. After 3 days of it becoming
increasingly irritating, I went to Specsavers and they washed it out free of
charge, and also gave me an eye test free of charge (presumably both in the hope
they could sell me expensive specs). But my eyesight was "surprisingly perfect
for a 40 year old - more like that of a teenager". I guess I never grew up :-)

I only saw the effects twice - not sure where the lightning came in, but a row
of 4 computers in a youth club had their soundcards fried (literally black in
places). Apart from short speaker cables to little computer speakers, I'm not
sure why the lightning would have gone in that way. The network cards were
fine, but then they tend to have surge arrestors (spark gaps) in them. Nothing
else on the computers were damaged. The other time was the network card in a
computer in someone's house - that could have been the phone line, although he
reckoned a small fork of the lightning came THROUGH the house and landed on the
phone cable running along the hall (his computer was fairly central in the
building).


Take it from me spark gaps where the voltages and currents that are in a
lightning strike as mere piffling things, thats why we use a lot of
heavy cross section Ally, used to be copper but the scrotes came for
that, all in order to shunt these currents around that what we need to
protect!...

Well not much would shield from a full strike, but often you get stray edges/forks of a strike getting through wires into computers, so a spark gap takes that off. If you got the main strike of lightning into your computer, the whole thing would literally explode - just look at trees that were directly hit, they split in two, explosively.