Getting a Good Ground
Getting a Good Ground
Getting a good ground is NOT just driving a ground rod. What makes a good ground in one location may not be a good ground somewhere else. When we design a facility like an airport or treatment plant or even something as simple as a pump station, we have to design a GROUNDING SYSTEM for each particular location. We measure the conductivity of the soil, and take into account the time of year tying to estimate how much moisture is in the soil, and what our likely worst case will be. I have yet to see anywhere that got a good ground with a single ground rod. In dry locations, we will require several chemical grounds and lots of copper interconnections between them in the ground.
Grounds are not just for personnel safety; having a good ground return path is essential for the correct operation of ground fault protection systems.
As for suppressors, protection has to be line-to-line and line-to-ground, because the same storm or event may give you either or both kinds of spikes, and it may required different devices to get good protection. Here again, every location has to be considered individually.
As some stated elsewhere in this thread, you can't protect against a direct hit from lightning or sometimes even a really hot near miss, but, luckily, those are few in most areas.
By the way, grounding for the power system is not the same as grounding for lightning protection. The power grounding currents go deep; lightning currents are shallow.