Chauvin Arnoux MH401 [P06234101] 250V / 1000V Insulation Tester. The Multimetrix MH 401 is a simple insulation knife that can measure insulation at 250, 500 or 1000 V for resistors up to 2000 Ω. The meter can also measure alternating voltages up to 600 V AC and test for continuity. It includes automatic compensation of the measurement cables, warns of the presence of voltage and offers the following other functions: timer, DATA HOLD, automatic shutdown.