The TA851 Series is a professional range of digital insulation resistance testers designed for electrical installation, inspection and maintenance. Also referred to as insulation testers, digital megohmmeters, insulation resistance meters or high-voltage insulation testers, the series includes the TA851A, TA851B and TA851C, with insulation test voltages ranging from 50 to 5000 V and resistance measurement up to 300 GΩ. In addition to insulation resistance, the instruments measure AC/DC voltage, resistance and continuity, and support Polarization Index (PI) and Dielectric Absorption Ratio (DAR) testing. Typical applications include transformers, instrument transformers, generators, motors, power cables, capacitors, surge arresters, switchgear and industrial electrical systems. Features include 99-set data storage, autoranging, automatic discharge, high-voltage indication and backlight display. The series is rated CAT III 1000 V / CAT IV 600 V, complies with IEC 61010-1 and meets Pollution Degree 2 requirements.