Two separate grounding pad inside a building. 2

[encon5]

We have 2 grounding pad at the basement of a new high rise building. The first is intended for indoor substation grounding while the second is intended for the lightning arrester grounding thru downconductor or downwire. The two pads are not connected to each other. This is the electrical designer’s idea. My question is, should the two grounding pads remain independent from each other. In other words there are two separate grounding system for the building? I hope you can follow what I’m trying to say. Would appreciate your response and possibly offer some advise or guidance. Thanks

Encon5

 

[dpc]

I'm not sure where you are located, but in the US, this would not be allowed per the National Electrical Code (NEC). The lightning protection ground and the electrical system ground must be bonded together. Other codes may be different.

Sometimes there is a perception that separating the lightning protection grounding system from the normal system grounding is a safer installation. But because of the enormous energy contained in a lightning strike, this is a bad assumption.

 

[slavag]

Hi.
I'm not sure, but it's some understanding, two diffrent grounding system in one building is some mistake.
I'm not designer, but from time to time I see in several place two grounding systems but in several points are connected (it's some "redandancy").
Regards.
Slava

 

[sslobodan]

Well they should be at the same potential on ground level if not the voltage difference may occur, Now I don't know about you but I certainly would not like to be between those 2 plates when lightning occur (One on ground potential and another on 10kV or more in that moment)

 

[groundperfect]

I agree that it is a very dangerous mistake. Getting between the separate grounds could be life threating with or without lighting.