HIOKI Earth Resistance Testers – Reliable Grounding for Safe Installations
Why is earth resistance testing essential?
Earth resistance testers – also known as ground resistance meters or ground testers – are indispensable instruments for electricians, facility managers, and maintenance engineers. These devices verify the effectiveness of grounding and earthing systems, ensure compliance with international safety standards, and protect people and equipment against electric shock, fault currents, and lightning strikes.
Depending on the installation, earth ground resistance testing can be performed using traditional two-pole or three-pole methods with auxiliary testing rods, or with modern clamp-on earth testers that measure grounding resistance without disconnecting the ground line. HIOKI models such as FT6031-50 and FT6041 enable fast, safe, standards-compliant checks in accordance with IEC 60364 and EN 61557-5. This makes HIOKI earth testers ideal for maintenance, inspections, and safety testing in residential buildings, commercial, and industrial facilities.
FT3151
FT3151 - ANALOG EARTH TESTER
The Classic Ground Resistance Tester FT3151 is equipped with an Easy Cord Winding System and operates using the AC potentiometer method. It offers both three-electrode and two-electrode measurement methods, which can be switched according to your needs. With measuring frequencies of 575 Hz and 600 Hz, the tester is designed for accurate and reliable ground resistance measurements. The measurement current is 15 mA rms or less for the three-electrode method and 3 mA rms or less for the two-electrode method. The open circuit voltage is 50 V AC rms or less, and the available resistance measurement ranges are 10, 100, and 1000 Ohm.Technical Details: Measurement methods: AC potentiometer method, Three-electrode method, Two-electrode method (switchable) Measuring frequency: 575 Hz / 600 Hz Measurement current:
o Three-electrode method: 15 mA rms or less
o Two-electrode method: 3 mA rms or less Open circuit voltage: 50 V AC rms or less Resistance measurement ranges: 10/100/1000 Ohm
FT6031-50
FT6031-50 - 2- and 3-pole earth tester
The Hioki FT6031-50 Earth Tester is a rugged and reliable instrument designed for measuring ground resistance using either the two-electrode or three-electrode method. With an IP67 rating for dustproof and waterproof performance, it is ideal for use in tough outdoor environments. The device features automatic pre-check functions for disturbance voltage and auxiliary grounding resistance, ensuring accuracy and efficiency. It also supports optional Bluetooth® wireless communication via the Z3210 adapter, enabling fast data transfer to smartphones or tablets for easy report generation. The FT6031-50 is engineered to withstand a 1-meter drop onto concrete, making it a dependable tool for fieldwork.Technical Information: Measurement system: Two-electrode / Three-electrode Measurement range: 0 to 2000 Ω Accuracy: ±1.5% rdg. ±4 dgt.Operating temperature: −25°C to 65°C Power supply: 4 AA (LR6) Alkaline batteries Dustproof and waterproof rating: IP67 Drop-proof: 1 m onto concrete Safety category: CAT IV 100 V / CAT III 150 V / CAT II 300 V
FT6041
FT6041 - Earth tester
The Hioki FT6041 Earth Tester is a versatile instrument designed for measuring earth resistance in complex ground systems using both the two-electrode and three-electrode methods. It offers IP67-rated dustproof and waterproof protection, making it highly durable for tough outdoor conditions.The FT6041 also features wireless communication support via the optional Z3210 adapter for seamless data transfer to mobile devices, enabling efficient report generation. With automatic checks for disturbance voltage and auxiliary earthing resistance, it ensures accurate measurements. Built for fieldwork, the device is drop-proof from a height of 1 meter onto concrete. Technical Information: Measurement system: Two-electrode / Three-electrode Measurement range: 0 to 2000 ΩAccuracy: ±1.5% rdg. ±4 dgt. Operating temperature: −25°C to 65°C Power supply: 4 AA (LR6) Alkaline batteries Dustproof and waterproof rating: IP67 Drop-proof: 1 m onto concrete Safety category: CAT IV 100 V / CAT III 150 V / CAT II 300 V
FT6380-50
FT6380-50 - CLAMP ON EARTH TESTER
The FT6380-50 is designed for multi-grounded systems, providing accurate true RMS measurements for leakage and load currents. It features high resolution and precision. Technical Details: Current range: 20 mA to 60 A Resolution: 0.01 mA / 0.1 A Accuracy: +/-2%rdg, +/-0.05 mA Measurement type: True RMS
FT9847
FT9847 - Signal induction clamp
The Hioki FT9847 Signal Induction Clamp is a key accessory for the FT6041 Earth Tester, designed to inject measurement signals during two-clamp earth resistance tests. This clamp ensures efficient and accurate measurements when used with the FT6041. It supports signal injection through conductors up to 52 mm in diameter or busbars with dimensions of 78 mm × 20 mm. With a maximum input current of 1000 A (for 1 minute) and a rated current of 50 A, it is ideal for precise signal injection in field testing. Built for tough conditions, it operates in temperatures from −25°C to 65°C and offers IP40 protection during storage. Technical Information: Maximum input current: 1000 A (1 minute, 45 Hz to 128 Hz) Rated current: 50 A (45 Hz to 128 Hz) Measurable conductor diameter: 52 mm or less Cable length: 2 mOperating temperature: −25°C to 65°C Dust and water resistance: IP40 (storage condition)Safety category: CAT III 600 V / CAT IV 300 V Connector: 4 mm banana plug
Product Comparison: Select your HIOKI Earth Tester
HIOKI offers a complete range from traditional clamp-on testers for quick checks in residential and small commercial sites to advanced digital meters with true voltage measurement and Bluetooth connectivity for use in demanding industrial environments.
| Feature | FT3151 Analog Earth Tester | FT6031-50 Earth Resistance Tester | FT6041 Earth Resistance Tester | FT6380-50 Clamp-on Earth Tester |
|---|---|---|---|---|
| Method | Analog tester with manual operation, 3- or 2-pole testing | Digital tester, 2- and 3-pole with earthing rods | Digital tester, 4-, 3- or 2-pole testing with earthing rods, clamp-on measurement | Clamp-on earth tester for multi-grounded systems |
| Earth resistance range | 0 – 1000 Ω | 0 – 2000 Ω | 0 – 300 kΩ | 0.02 – 1600 Ω |
| No. of individual ranges | 3 ranges: 10 / 100 / 1000 Ω | 3 ranges: 20 / 200 / 2000 Ω | 6 ranges: 3 / 30 / 300 / 3000 Ω, 30 kΩ / 300 kΩ | 10 ranges: 0.2 / 2 / 20 / 50 / 100 / 200 / 400 / 600 / 1200 / 1600 Ω |
| Safety category | CAT II 300 V | CAT IV 100 V / CAT III 150 V / CAT II 300 V | CAT IV 100 V / CAT III 150 V / CAT II 300 V | CAT IV 600 V, True RMS |
| Power supply | Batteries | Batteries | Batteries | Batteries |
| Highlights | Rugged, simple, ideal for basic checks | Lightweight, easy stake setup, IP67 protected | High accuracy, extended range, IP67 protected | No rods needed, fast clamp measurement |
Made in Japan – Built for Lasting Precision
All HIOKI earth testers are designed in Japan and manufactured at our own R&D center and factories, ensuring the highest standards of precision, reliability, and lasting accuracy trusted by technicians worldwide.