I got a call from our monitoring station Wednesday night. The assisted living home I've been installing a number of low voltage systems in had taken a lightning strike, and they wanted me to get things in hand. I won't bother with the litany of evaporated components and troubleshooting hassles; suffice it to say the bill is probably pushing $14,000.00 so far, and I'm not done yet.
Surge protection? Plenty. Grounding? That's where my issue lies. All this has raised an old arguement that I have had, mostly with myself, about what grounding is really for, and I'm hoping the Fine elctrician(s) that read this missive will chime in.
I have maintained for some time now that grounding is to protect people, not equipment. In fact, with what little I've read on the behaviour of lightning, it seems grounding is usually the path that this terror takes on its way to your stuff. Illustration: Take a solid silver ground rod and drive it all the way to the planet's mantle. Wrap a 4AWG around it, clamp it and weld it to the rod, leaving a 6' long tail. Now, imagine there is tree 50' away that it is going to get hit by an average strike in 15 seconds. Are you willing to hold on to that tail? To me, common sense says that all that current is not going to take a 90 degree turn and head for China. Some of it is going to energize that tail, or your wiring system.
How am I doing?
Jeff