The Megger 250574 three-piece test lead set includes three test leads and is for use with the Megger 250260 ground resistance tester. One test lead is 12' (3.6 m) long, one is 31' (9.4 m) long, and one is 50' (15 m) long. The test leads are color-coded to help ensure proper connection.
A test probe, test lead, test prod, or scope probe transmits an electrical signal to a testing device for display and analysis. Designs range from simple test leads with probe-style or clamp-on tips to more complex oscilloscope probes and current detectors. Some test probes, such as basic test leads, have wires with tips for connecting to test equipment. Other test probes, such as voltage detectors, are built into the meter. Depending on what is to be tested, the probe might either be passive or have active parts that require external power to operate. Some probes require contact for testing, while some are capable of taking measurements from a distance. Some also have finger barriers, insulation, or other features to help protect the operator's hand from electrical shock and burns. Test probes are rated according to the amount of voltage, current, temperature, or other input they can measure. When choosing a test probe, the maximum amount of input that the probe can measure should match or exceed both the maximum amount that can be tested by the test equipment, as well as that of the property expected to be present in the application.
Megger manufactures equipment for cable fault locating, protective relay testing, telecommunications and data integrity, and power quality testing under multiple brand names, among them Megger, Biddle, States, and AVO. The company, founded in 1889, is headquartered in Dover, England, and meets International Organization for Standardization (ISO) 9001:2008 standards.