I measured my Ze by disconnecting earth and testing between Earth and Live at the CU = 0.12 ohms.
I previously have done all the R1+R2, and in particular have a reading of 0.18 ohms on a short radial, and 0.21 ohms on the ring. These tie up with what I should expect to see when comparing the resistance per metre for the csa of the cable, so am satisfied that these are correct.
So Zs calculated would be 0.30 for the radial and 0.33 for the ring, but I am getting readings using the NO TRIP option on the Megger of 0.66 ohms fior the radial and 0.75 ohms on the furthest ring socket. While these are well within the limits, why is it higher?
Any takers?
I previously have done all the R1+R2, and in particular have a reading of 0.18 ohms on a short radial, and 0.21 ohms on the ring. These tie up with what I should expect to see when comparing the resistance per metre for the csa of the cable, so am satisfied that these are correct.
So Zs calculated would be 0.30 for the radial and 0.33 for the ring, but I am getting readings using the NO TRIP option on the Megger of 0.66 ohms fior the radial and 0.75 ohms on the furthest ring socket. While these are well within the limits, why is it higher?
Any takers?