UNI-T UT521 Digital Earth Resistance Tester

UNI-T UT521 Digital Earth Resistance Tester in Sri Lanka

Manual-Range 3-Pole Earth Pit Tester

The UNI-T UT521 Digital Earth Resistance Tester measures earth electrode and ground rod resistance using 3-pole fall-of-potential testing. It is a practical choice for electricians, maintenance teams and electrical contractors in Sri Lanka who need to check earth pits, grounding electrodes and earthing systems at buildings, factories and distribution installations. Browse our full range of earth resistance testers in Sri Lanka.

The UT521 uses manual range selection across 200Ω, 2kΩ and 20kΩ, with a 3½-digit LCD for straightforward field readings. Its interference-voltage detection helps identify AC voltage that may affect a measurement, while the handheld design supports routine earth pit testing and periodic grounding inspections.

Technical Specifications

Earth Resistance Range

0~200Ω | 0~2kΩ | 0~20kΩ | manual range

Resolution

0.01Ω on the 200Ω range

Accuracy

±(2% + 5 digits) on 200Ω | ±(3% + 5 digits) on 2kΩ and 20kΩ

Test Methods

3-pole and 2-pole earth resistance measurement

Test Frequency

Approximately 820Hz

Interference Voltage

AC up to 30V detection

Auxiliary Electrode Resistance

Up to 50kΩ for current (C) and potential (P) electrodes

Display

3½-digit LCD

Power

6 × 1.5V AA batteries

Dimensions

Approximately 195 × 90 × 52 mm

Key Features

Manual Range Selection

Select 200Ω, 2kΩ or 20kΩ according to the expected earth resistance value

Interference Voltage Check

Warns when AC interference up to 30V is present before testing

3-Pole and 2-Pole Modes

Use the standard fall-of-potential method or a simplified 2-wire check where appropriate

Field-Friendly Design

Compact handheld body for earth pit and ground rod testing across multiple sites

Auxiliary Electrode Tolerance

Supports auxiliary electrode resistance up to 50kΩ, helping reduce setup issues in higher-resistance soil

Applications

• Earth pit resistance testing at factories, workshops and substations
• Ground rod verification for residential, commercial and industrial installations
• Periodic earthing inspections for electrical compliance and maintenance records
• Grounding checks at telecom sites and lightning protection systems

Buying Guidance

Choose the UT521 when you need a dependable manual-range earth tester for standard 3-pole earth pit measurements. If you prefer automatic range selection for faster repeated testing, compare it with the UNI-T UT522 Digital Earth Resistance Meter. For soil resistivity and 4-pole testing, see the UNI-T UT572 Advanced Earth Ground Tester.

Package Includes

• 1 × UNI-T UT521 Digital Earth Resistance Tester
• 3 × Test leads for E, P and C terminals
• 2 × Auxiliary earth spikes
• 6 × AA batteries
• Carrying case
• English user manual

Downloads

📄 Download UNI-T UT521 Data Sheet
📄 Download UNI-T UT521 User Manual