What do you mean electrical earth pit?

Usually a vertical grounding electrode –made of copper, copperweld steel, stainless steel or else-and length of3-20 m is driven in earth and the upper end will be exposed in a pit covered by a lid- about0.3-0.6 m deep and0.3 m diameter. This pit facilitates electrode connection with horizontal grounding conductor and as a check point of electrode state- grounding [earthing] resistance measurements and other.