Megger MJ159 – Major Insulation Resistance Tester

• Four selectable DC test voltages: 100, 250, 500 and 1000 V.
• Measures insulation resistance to 2000 MΩ plus low-resistance to 5000 Ω.
• External guard terminal eliminates surface leakage errors.
• Automatic capacitive discharge and live AC voltage detection for safety.
• Compact, rugged ABS case with no scale multipliers and easy hand-crank operation.

The Megger MJ159 stands out as the trusted hand-cranked insulation tester that delivers dependable performance without batteries or external power. Technicians rely on its four selectable voltages to perform fast, accurate spot and step-voltage checks on motors, generators, cables, transformers and switchgear. The guard terminal actively removes surface leakage effects, ensuring precise readings up to 2000 MΩ every time. In addition, the built-in low-resistance range and live-voltage warning add practical versatility and essential safety. Automatic discharge clears capacitive loads instantly, so operators remove test leads with complete confidence. Lightweight yet robust, the MJ159 continues to prove its lasting value for commissioning, maintenance and diagnostic work across industrial and distribution sites.