QRS Calibrations offers high quality resistance testers manufactured by Extech Instruments. Extech resistance testers include ground resistance testers, and clamp-on ground resistance testers. Specific models also measure earth, AC and DC voltage and perform measurements in varying ranges. All of these resistance testers are ISO 9001:2008 certified by TUV.
Resistance testers measure ground resistance and, depending on the model, a range of values including ground rod resistance, grid resistance, soil resistivity, earth coupling measurement, and bonding tests. Some resistance testers can perform non-contact measurement of ground conductors.