In article , Martin Brown
scribeth thus
On 05/04/2021 16:15, Dave Plowman (News) wrote:
On another group, I heard about a lightning strike to a house, via the TV
aerial. Aerial went to a DA. Seemed it burnt out all the house wiring and
every appliance in it. Requiring the owners to move out for months while
it was all sorted. Seems it also travelled to other houses in the street
too via the mains and caused much damage there too. Was rather surprised
to read this. I've seen a TV destroyed - but not so much extra damage.

It seems quite unlikely. Our VH has taken the odd hit and whilst it
takes out the mains for a while the emergency lights survive OK.

A building I was in at work took a big direct hit that found its way
into the internal telephone network deafening the lady on the
switchboard who was unconsolable afterwards (as in it took about a day
to recover her hearing) .

Vapourised the phone cabling in the trunking leaving nasty black marks
on the wall. We felt very aggrieved that the strike hit our apex rather
than the much higher supergrid pylon 100m away. Capricious stuff is
lightning. It was one of those big industrial sheds with a metal roof.

Well look up the "rolling ball" method of assessing a strike likelihood
they very often come in from the side as thats to the strike, discharge
rather! is coming from so the side of a church or building is a better
path to ground than that pylon or mast that you might think was the
better target!...



Induced currents blew out some of the more delicate parts of the
mainframe interface boards whilst the surge suppressors saved themselves
by allowing other more delicate (ie. expensive) components to fry.

Once the damage was assessed we were back on mains power fairly quickly.
Emergency diesel generator cut in for critical systems as the mains went
down. Smelly noisy thing but at least it worked on the day! Internal
phone system was down for most of a week - complete rewire needed.

I have had modems killed by close lightning strikes but that is about
it. You can't rule it out but it must be very unlikely. Most times the
UPS or emergency backup power maintains full operation.

You would have to be very unlucky for it to damage mains wiring but if
it does then the huge currents involved can be very destructive.


--
Tony Sayer


Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.