The Reading Will Gradually Increase and Stabilize at the True Insulation Resistance. Therefore, the timing of reading is critical
2026 Key Indicators and Purchasing Pitfall Avoidance
Modern insulation resistance testers are highly intelligent and no longer simple crank megohmmeters. When purchasing, pay attention to the following parameters:
Core Parameter Pitfall Avoidance
Table
Focus Point Pitfall Avoidance Advice Description
Short-Circuit Current Recommended > 3mA (even 5mA) This is the most important indicator! The higher the current, the stronger the load capacity. When testing long cables or large-capacity transformers, charging speed is fast and data is more stable.
Test Voltage Multiple selectable ranges Low-voltage equipment (such as 380V motors) select 500V/1000V range; high-voltage cables (above 10kV) need 2500V/5000V/10000V range.
Measurement Range 0 ~ 200GΩ (or higher) With the advancement of insulation materials, resistance values are getting higher. Too small a range will cause an overflow display (showing 1 or OL) and prevent reading.
Anti-Interference Capability Must have G terminal (Guard terminal) Field environments are complex. The G terminal can shield surface leakage current and electromagnetic interference, ensuring that volume resistance rather than surface resistance is measured.
Display Mode Dual Display (Analog + Digital) Digital display provides accurate readings, while the analog pointer shows the trend (such as absorption process). The combination of both is most intuitive.
