Clamp-on earth resistance testers have jaws that fasten around conductors connected to grounding points in an electrical system to measure resistance to current. These handheld, portable instruments take fast and accurate readings without physically touching conductors or can be used with ground probes. Often used where space is limited, they also confirm resistance levels of existing grounding points and do not require any disruption to the power supply before use. Applications include 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.