UNI-T UT502A Digital Insulation Resistance Tester

Electrical insulation degrades over time due to moisture, heat, and mechanical stress, leading to dangerous leakage currents and potential equipment failure. The UNI-T UT502A Digital Insulation Resistance Tester provides a reliable, portable solution for verifying insulation integrity in motors, cables, transformers, and switchgear. With five selectable test voltages up to 1000V and a measurement range reaching 5.5GΩ, this meter delivers accurate diagnostics for preventive maintenance and safety compliance.

Who is it for

Designed for electricians, maintenance technicians, and industrial engineers who need to assess insulation condition in low-voltage installations, appliances, and rotating machinery. Its compact size and rugged build make it suitable for both field service and workshop use.

Main features

• Five insulation test voltages: 50V, 100V, 250V, 500V, 1000V
• Measures insulation resistance up to 5.5GΩ
• 6000-count backlit LCD with analogue bar graph
• Polarization Index (PI) and Dielectric Absorption Ratio (DAR) calculation
• AC/DC voltage measurement up to 1000V DC / 750V AC
• Low resistance continuity test with buzzer (<30Ω)
• Data hold, auto power off, and low battery indication
• Safety rated CAT III 1000V / CAT IV 600V

Specifications

• Insulation test voltages: 50V, 100V, 250V, 500V, 1000V
• Max insulation resistance: 5.5GΩ at 1000V
• Insulation resistance accuracy: ±(3%+5) for most ranges, ±(5%+5) for higher GΩ
• Short circuit current: <2mA
• DC voltage range: 0V to 1000V
• AC voltage range: 30V to 750V
• Resistance range: 0.01Ω to 20kΩ
• Continuity test: Yes, with buzzer (<30Ω)
• Display: 6000-count backlit LCD with analogue bar graph
• Special functions: Polarization Index (PI), Dielectric Absorption Ratio (DAR)
• Safety rating: CAT III 1000V, CAT IV 600V
• Power source: 6 x 1.5V AA batteries
• Data hold: Yes
• Auto power off: Yes
• Low battery indication: Yes
• Over-range indication: Yes

Tips

For accurate insulation testing, ensure the circuit is de-energized and discharge any capacitive loads before connecting the tester. Use the PI and DAR functions to assess insulation quality over time and detect moisture or contamination issues. Replace batteries when the low battery indicator appears to maintain measurement accuracy.