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Old 19th Oct 2017, 6:28 pm   #4
GrimJosef
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Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 4,311
Default Re: Lightning protection zones

I wouldn't trust anything more open than a substantial metal box to protect me from lightning. The peak currents can be terrifyingly large and can set up considerable potential differences even as they flow through quite good conductors. There's quite a well known phenomenon where a farmer turns up to find multiple dead cattle in a field. The bodies are arranged in dartboard formation, all lined up radially around a central point. Other cattle in the field seem unharmed, if distressed. What happens is that lightning strikes a point on the ground and the current then flows radially outwards through the soil. Any cattle unfortunate enough to have their front legs close to the strike point and their rear ones much further away (or vice versa) are electrocuted by the voltage difference between their front and rear legs. Any who who are standing sideways to the direction of current flow only get a relatively small voltage applied between their left and right legs. They might end up deaf in one ear though.

I was in a building which was struck by lightning once. It's not something you forget in a hurry.

Cheers,

GJ
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