Earth rods and their fittings are used to provide the interface to ground in all soil conditions in order to achieve satisfactory earthing systems in overhead and underground electricity distribution and transmission networks - providing high fault current capacity on low, medium and high voltage substations, towers.
If a charged ebonite rod is earthed electrons flow from earth to the ebonite rod if it is positively charged and if it is negatively charged electrons move from the rod to the earth.
The only purpose of a ground rod or a group of ground rods forming a ground field is to have a designed electrical path to dissipate a static discharge voltage (which can be lightning or other forms of static electricity) to the earth.