Ok Guys, I love all off this Stuff but it's consider;
- The neutral and ground in the main panel are Bonded and therefore the same potential in the main panel. There need be no ground from the meter to the panel as the neutral is the same potential as ground at that location and bonded to ground in the panel.
- A grounded conductor (ground wire) must run to the remote building that has a sub-panel and be mounted to the ground lug in the sub-panel, which is bonded to neutral inside the main panel.
- The grounded conductor to the remote building must connect to a ground rod with specified maximum resistance (or two ground rods by continuous ground wire)in the sub-panel. This means that the ground should have the same potential as the main panel ground and the main panel neutral, unless there is induced charge from some source (a Neighbor's house or pool, or bad transformer, etc).
- The neutral in the sub-panel is NOT bonded the the ground in the sub-panel. Therefore it will carry any current back TO the MAIN panel, instead of attempting to dump it into the remote building's ground.
(Examine this: you have 6 circuits, 3 on A leg and 3 on B leg in the remote building. There are 14.5 amps active on A and 36 on B leg. The Neutral is carrying 36-14.5= 21.5 amps back to the main panel and MUST do so....or you would be imbalanced in the main, and possibly causing the problem listed in 3 above to your neighbor!!!).
Now we can examine a lightening strike. The way to cause lightening to WANT to strike is to set up a grounding plane and connect it to a tall sharp metal object. Bury 300 or whatever ft of wire in a circle and bring the end(s) to the middle of the circle. Attach them to a pole with a sharp tip, slightly higher than anything else around it. If the POTENTIAL for lightening approaches, the ground plane prepares the availability of electrons. When the potential is great enough the electrons RISE from the EARTH to the area of positive charge. Lightening strikes UP, not down. In sand, the heat generate by this kind of strike (electron flow) can turn the sand to glass with interesting fractal structures.
Houses used to be struck very often, church steeples even more often. However today we have power poles above ground with neutrals attached to ground rods everywhere. It is very unlikely to have a building struck by lightening directly as they are mostly lower than trees and power poles etc. IT does not matter whether it is your house, the transformer, your air compressor or any other device, the surge WILL come to your house through those lines and the earth. Best protection is a surge protector designed to capacitate, blow the caps instantly and blow your house main breaker or branch breaker in the process. This device will NOT protect electronics (you can do that but it is expensive and should be done by charging batteries and inverting thereby maintaining clean power separated from the grid). This surge protector generally WILL protect motorized equipment (AC compressors, washers/dryers, refrigerator motors, etc).
IF you have a surge protector, you should have one at each disconnect panel or sub-panel or even receptacle (to any exterior device). Example" pool pumps, well pumps, detached garages, AC Compressors, Pool Heaters etc. They are on concrete pads or poles which are excellent conductors (especially when wet, even wood when wet) and can help create the ground plane. Surge protectors need to be at every possible point of entry to the house that can be in that ground plane.
The Illinois Railway museum probably just needed a very good lightening rod and ground to their roof...or lightening rod on a tower higher than the roof and with a good grounding plane, to control any strike location. My guess is that the sub-station reduced the contracted cost of electricity substantially, and therefore was dual purpose and effective.
IS the GROUND System to protect from lightening strikes?
House grounds are specifically designed for PERSONAL SAFETY. Originally, there were no grounds. Most devices had metal casings. IF the hot came loose, no harm no foul, the device stopped. If the neutral came loose heaven help the poor guy squeezing the handle of the drill or touching the metal blender, the person became the NEUTRAL/Ground, and many homes had great conductors for floor materials and even water around. By having a ground, if the neutral fails, power is shunted to the ground, reducing the potential and saving the HUMAN from severe harm. Many devices can cause the circuit to blow when the neutral is loose and power is returned through the ground. I hope this helps resolve confusion about the code and the why.
Does the grounding system protect against lightening strikes? It does provide a more direct path to ground and therefore MAY help, however I would suggest that it might be the other way around. Because the path is more direct, it might actually increase the likelihood in some respect, however, it would most probably severely reduce any damage to structure.