Grounding.
Drawing labels, details, and other text information extracted from the CAD file (Translated from Spanish):
legend, Bronze copper connector, Shell dlg, Ohms, denomination, date, scale:, C.d.p:, flat:, Chrome plating, Naked, Bronze copper connector, Copper rod, Sieved compact earth mixed with kg. from, Well protection earth, Of grounding protection according to the standard you have, Shell dlg, Ohms, Resistivity of the ground length of the buried rod rod diameter ground resistance, Shell dlg, Ohms