IEEE 80

[IndianTechEngg1001]

My question is. In IEEE 80, Why in fig 33, step 2 is required initially? Is it having influence in next calculations.

Thanks in advance

 

[jghrist]

You need to know the conductor size requirements to prepare an initial design (Step 4). You don't need it for Step 3, so you could do Step 3 before Step 2.

 

[IndianTechEngg1001]

Thanks jghrist

Yes I also got it. It has been used in Mesh Voltage Calculation (Touch Voltage)

 

[odlanor]

I do not agree.
step 2 is only to dimension cable to support short-circuit current (3I0) and the time (tc) duration of short circuit.

Grounding grid is dimensioned to find an adequate arrangements of cables in order to guarantee shock Calculated Potentials are less then shock Tolerable Potentials for a ground current (Ig) during a shock time(ts).