Nec 250.94 & 800.100(b)

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funseebee

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We showed a detail of the telephone backboard with the ground bar on it and connected to a 5/8" dia X 10' long ground rod via #6 bare, copper wire.

But still we were required to show the telephone equipment grounding in compliance with NEC 250.94 & 800.100(B). We don't what is still missing on our detail. please help. :confused:
 
The purpose of 250.94 is to create a single point ground and have all equipment referenced to the same location to minimize differences of potential in a lightning event. Your isolated ground rod does nothing but keep the ground rod companies in business.
Read the definition of intersystem bond in Art 100.
 
The problem is that separate, non-interconnected electrodes can actually force a potential difference under certain conditions where the desire is to have no differences.

Nearby lightning, for example, can create differences of several hundred volts between isolated ground rods, which can damage otherwise-interconnected equipment.
 
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