Lets Play Sherlock Holmes - The lightning incident.....

[Bob B]

OK yep it was a voltage surge protector. My original comment stands. Connecting it to separate unbonded ground rod was very wrong way to do it.

You didn't answer my question .... where would you be shunting the voltage spike? Nothing had any path to ground til the lightning strike occurred.

2 of these companies were fortune 500 countries with the engineering for this type thing done at a corporate level .... Maybe I can put you in touch with their engineers.

 

[AntronX]

You didn't answer my question .... where would you be shunting the voltage spike?

To a common low impedance ground point so that differential current across the lines entering your building would not develop. You don't actually need to shunt it to earth ground, you need to shunt it to a common point of a ground system akin to a Faraday cage. This is why being inside metal car keeps you safe from lighting even if the car is not grounded. But that is also not completely correct way of protecting your equipment from lightning surges. All your lines entering the building have to enter at one physical point or be routed to one common ground point before fanning out to you equipment. This is called single point grounding. This eliminates a possibility of differential current developing across lines due to ground system impedance that will always be there.

2 of these companies were fortune 500 countries with the engineering for this type thing done at a corporate level

I am sorry to hear that.

 

[Bob B]

To a common low impedance ground point so that differential voltage across the lines entering your building would not develop. You don't actually need to shunt it to earth ground, you need to shunt it to a common point of a ground system akin to a Faraday cage. This is why being inside metal car keeps you safe from lighting even if the car is not grounded. But that is also not completely correct way of protecting your equipment from lightning surges. All your lines entering the building have to enter at one physical point or be routed to one common ground point before fanning out to you equipment. This is called single point grounding. This eliminates a possibility of differential voltage developing across lines due to ground system impedance that will always be there.

I am sorry to hear that.

Guess we are going to have to disagree ..... The last place I would want to shunt a lightning strike it to a common ground that would be blown open and voltage surged to every piece of equipment attached to it.

 

[AntronX]

The last place I would want to shunt a lightning strike it to a common ground that would be blown open and voltage surged to every piece of equipment attached to it.

If a strike causes your grounding system to blow open then conductors were not large enough. You actually do want strike voltage to rise equally across all equipment (common voltage) so that differential current across equipment does not develop which is what does the damage.