On Fri, 5 Jan 2018 09:45:14 -0800 (PST), Its Me
wrote:


I'm familiar with the type of grounding system you're describing. I've working in many equipment rooms over the years with all types of RF and communications equipment, and they almost always have the copper flashing and bars for grounding the equipment.

The craziest thing I ever saw was a fire lookout tower on top of an 8k foot mountain in northern CA. It was a 3 story structure with something that looked like a chain-link fence around the roof, with huge cables coming down all four corners, then across the stone mountaintop with rods driven into the stone every so often for maybe 100 feet.

This was for lightning protection. It's not the lightning that kills the equipment, it's the difference in potential that kills equipment. So the idea is to get the building, equipment (and ground system) inside the building, and the mountaintop to all rise up to the lightning potential together, then drain back down together. They said it got struck several times every summer with rare losses. Probably pretty exciting for the person inside!

It had one other interesting feature... a scuttle hole on the roof with a ladder partially down one side of the building. That was for winter access when they used snow cats to get up there. I was there in the summer.

They do a similar thing for radio towers and strangely, toll booths.
Around here "Ground" is just a vague reference to zero volts so they
really need a lot of electrode to get the job done. In both the radio
towers and the toll complex they used a buried ground ring of braided
#2 copper around the whole complex with 40' rods cad welded every 50
feet or so all the way around the ring. At the toll complex (MM99
I-75) it looked like the 4th of july when they were firing all of
those cad welds.
My weather station on the garage has a 3/8" lightning rod over it with
a #2 copper going to 3 rods that is also connected to the GES for the
service and everything else. It has been hit several times and not
hurt anything here after I hung some ferrites on the data lead coming
down. Before that I did take put a serial port on a laptop.