This is often ever more difficult versus a backdrop of higher fault degrees, smaller sized-space substations and the more common usage of delicate electronic products both equally at the substation and by external third parties, the place the affect of transferred earth potentials might need to be mitigated. NFPA 780 https://www.zupyak.com/p/4222457/t/innovative-approaches-to-symmetrical-fault-diagnosis-in-power-systems