Finrod_Felagund Browser Join Date: Jul 2007 Location: Arica – Chile Posts: 2 #1 Re: The best route for earth conductor running 07/22/2007 1:07 AM For the Fault Calculation you need to the zero sequence impedance, so in a trifasic line with neutral conductor the zero impedance is: Z0=Z0A – (ZOAG)2/Z0G ?/m with: Z0A=three times the self impedance of an equivalent conductor of the three phase line (without the neutral conductor) Z0G=three times the self impedance of the neutral conductor Z0AG=three times the mutual impedancia between the equivalent phase conductor and the neutral conductor. As you can see, for a lower zero impedance we required to maximized the mutual impedance between the phases and the neutral, and you can get this with closer neutral conductor to the phase conductors.