Earth resistance measurement for high potential installations needs to be accurate and safely performed. Metrel make an earth resistance tester for every circumstance, and their step- and contact-voltage testers offer excellent user protection. These include: The MI 3123 SMARTEC, which offers 4-wire earth resistance testing in a convenient, hand-held unit. The MI 2126 Earth 2/3, a hand-held 3 wire earth. The MI 3295 Step Contact Voltage Measuring System which offers protective earthing testing for power stations, substations and other major power installations.