Earth ground testers measure the soil's resistance to electrical currents and determine its effectiveness for grounding electrical systems. These handheld instruments pair with insulated test leads which connect to electrodes or probes buried in the soil at specific depths. They generate an AC current that runs through the electrical system under test in addition to these buried probes to calculate electrical resistance levels. Earth ground resistance testers are often used for utility stations, electrical distribution systems, industrial plants and facilities, and telecommunications systems. They help find suitable areas to ground electrical systems to protect people and equipment from lightning strikes, electrical faults, and other dangerous conditions that could lead to electrical shocks, explosions, and fires. Additional applications include finding underground areas that may cause corrosive damage to underground pipes and water lines.