The Megger DET24C digital clamp-on ground resistance meter measures ground resistance in multi-ground electrical installations and lightning protection systems without needing to disconnect the ground in electrical testing applications. It has a clamp with two jaws that can close around round cables and rods up to 1.45" (37 mm) in diameter and ground tapes and straps up to 1.96" (50 mm) wide to measure resistance without disconnecting the ground. The meter also provides true RMS (root mean square) measurements of current up to 35 amp to help ensure operator safety during operation. The meter has a user-selectable noise filter to allow measurements to be taken in areas with high amounts of electrical noise. The meter's internal data storage allows multiple results to be compared and tracked over time, and readings are date and time stamped. It comes with a software that provides a graphic user interface for working with the data on a computer. An alarm notifies user when user-selected minimum and maximum values for current and resistance are reached or exceeded. The hold function keeps a reading on the display, even after the meter is disconnected. In applications where the conductor is difficult to access, an auto-hold feature allows a reading to be captured without requiring the operator to press the button during measurement. The meter's liquid crystal display (LCD) is backlit to provide readability in low light. The clamp jaws have a smooth surface with no interlocking teeth to help prevent build-up of dirt and residue, which can interfere with measurements. The unit automatically turns off after five minutes of non-use to conserve battery life, and a low-battery indicator signals when the meter's batteries need to be replaced. This Megger earth test clamp-on ground resistance meter meets International Electrotechnical Commission (IEC) safety standard 61010 and is certified for category IV installations up to 600V, which covers measurements at the source of the low-voltage supply, such as electricity meters and overcurrent protection devices. The meter has a wrist strap and comes with a hard plastic carrying case to protect the meter from damage during transport and storage. A finger guard on the body of the meter helps protect fingers from shock.