Grounding Wire Sizing
Grounding Wire Sizing
(OP)
It states in IEEE80 that grounding wires shall be sized to withstand the fault current. But it doesn't say it is 3 phase fault or L-G fault. My understanding is, it is 3 phase fault, since under L-L-L-G fault situations, Grounding wire will have to withstand 3 phase fault, even though it is high resistance grounding system.






RE: Grounding Wire Sizing
If there is no Ground involved, where would all the current go in a 3 phase fault?
Why do you think, 3 phase fault current will flow through the ground conductor during an L-L-L-G fault? Even if yes, will it be the full value of 3 phase fault current?
There is a reason LLL-G faults are treated as just 3 phase faults.
Rafiq Bulsara
http://www.srengineersct.com