12 Apr MRU-120, MRU-200, MPI-530 – Can I use the double clamp method for every type of earthing?
Only for the multiple earthing measurements, but not connected underground, as the current flowing through the tested earthing must flow in a circuit closed by the earth.
The double clamp method cannot be used for single earthing, nor the ground rings.
This method is described in “Guide to PN-EN 62305 Standard. Measurement of earth resistance” (link).