Megger MIT400/2 MIT Series Insulation Resistance Testers

Megger MIT400/2 is a CAT IV-rated insulation and continuity tester from the renowned MIT400 mk2 series. It is designed for professionals in electrical engineering, industrial maintenance, cable testing, motor repair, automotive, avionics, and panel building . As the successor to the original MIT400 series, this instrument combines enhanced safety, faster testing speeds, and greater accuracy, making it an essential tool for electricians and engineers who require reliable day-to-day diagnostic capabilities .

Key Insulation Testing Capabilities

The MIT400/2 performs insulation resistance testing at fixed voltages of 250 V, 500 V, and 1000 V, with a maximum measurement range of 200 GΩ . A standout feature is its stabilised insulation test voltage, which uses feedback control to limit overvoltage to just +2% -0% of the selected range. This is a significant improvement over the industry standard of ±10-20%, providing precise test conditions without risking over-voltage damage to sensitive circuits or components .

For applications requiring non-standard voltages, the MIT400/2 offers a variable test voltage mode from 10 V to 1000 V, adjustable in 1 V steps below 100 V and 10 V steps above 100 V .

Continuity and Voltage Measurement

Continuity testing has been significantly improved with a single, auto-ranging function covering 0.01 Ω to 1 MΩ, replacing the separate "ohms" and "kΩ" ranges found on older instruments . The tester outputs a test current of 200 mA (0.01 Ω to 4 Ω range), with open circuit voltage of 5 V ±1 V, and includes a lead null function to subtract test lead resistance up to 10 Ω .

For voltage measurement, the MIT400/2 measures 600 V TRMS AC and DC, with a 0.25 MΩ input impedance and frequency measurement from 15 to 400 Hz . Additional functions include capacitance measurement (0.1 nF to 10 μF, ±5% accuracy), as well as Polarization Index (PI) and Dielectric Absorption Ratio (DAR) calculations for evaluating insulation quality over time .

Safety and Durability

Safety is a primary focus of the MIT400/2. It features live circuit detection and test inhibit protection, preventing insulation tests if hazardous voltage is present . The instrument is rated CAT IV 600 V / CAT III 1000 V and has an IP54 weatherproof rating, making it suitable for use in dusty or damp environments . The redesigned case features an over-moulded rubber housing for impact protection, a built-in back stand for bench-top use, and separate battery/fuse access compartments .

General Specifications

Power Supply: 6 x AA (LR6) alkaline or NiMH rechargeable batteries 

Battery Life: Approximately 3000 insulation tests (5 sec ON/55 sec OFF duty cycle at 1000 V into 1 MΩ) 

Dimensions: 228 x 108 x 63 mm (9 x 4.25 x 2.32 inches) 

Weight: 600 g (1.32 lbs) 

Display: Digital display with an analog arc for observing trend changes 

Operating Temperature: -10°C to +55°C 

The Megger MIT400/2 combines the heritage of the original insulation tester with modern enhancements in accuracy, safety, and ease of use, making it a versatile and trusted choice for electrical testing professionals worldwide.