FT6380-50 - Earth Ground Clamp for Multi Grounded Systems

Key Specifications

• Ground resistance measurement without disconnecting the earth conductor 
• Ground resistance: 0.02 Ω to 1600 Ω
• Conductor diameter up to 32 mm
• AC current measurements up to 60 A 
• Optional Bluetooth communication with Z3210 adapter 

Typical Applications

• Grounding checks on transmission towers, tanks and industrial plants 
• Ground checks on lightning protection and PV systems with multiple earth paths
• Leakage current and load current measurements up to 60 A 

Detailed Product Overview

The HIOKI FT6380-50 Earth Ground Clamp is designed for testing grounding systems with multiple parallel earth paths. It measures the resistance of the earth connection directly on the connected earth conductor, without disconnecting the conductor.

Typical applications include grounding checks on transmission towers, storage tanks and industrial plants, as well as on lightning protection systems and PV installations with multiple earth paths. The clamp also supports leakage current and AC current measurement up to 60 A, accommodates conductor diameters up to 32 mm and complies with CAT IV 600 V.

Ground resistance measurement in multiple earthed systems 

The measurement principle uses two separate coils in the clamp head. One coil inductively couples a test voltage into the earth conductor inside the jaw, while the second coil detects the resulting current. For this method to work, multiple parallel earth paths must be present so that a test current can flow. At least two parallel earth paths are required. 

For resistance measurement, the instrument provides 10 ranges from 0.20 Ω to 1600 Ω. The lowest specified measurement value with stated accuracy is 20 mΩ. Range selection is automatic, and the measured value can be frozen on the display with the HOLD key. For work in dimly lit environments, the display is equipped with a switchable backlight. 

Leakage current, load current and additional functions

In addition to measuring the resistance of the earth connection, the FT6380-50 also supports AC current measurement. With its lowest current range of 20 mA, the clamp can detect small leakage currents, while load currents up to 60 A can also be measured. Current is measured using a True RMS method. 

A selectable filter function acts as a low pass filter during current measurement and suppresses higher frequency components, such as those caused by switching power supplies or inverters. During resistance measurement, the filter function stabilizes the display by averaging the measured values. 

A configurable threshold alarm is also available and can be set separately for resistance measurement and current measurement. The internal memory can store up to 2000 readings from both functions. 

Optional Bluetooth communication 

With the optional Z3210 adapter, the FT6380-50 can be expanded with Bluetooth communication. Readings can be transferred to a smartphone or tablet and documented in the GENNECT Cross app. The app supports linking readings with photos, maps, and additional information from the measurement site. In HID mode, the clamp sends readings as keyboard input directly to the selected application, for example to Excel or to input fields in custom software solutions. 

The FT6380-50, powered by two LR6 batteries, provides a typical operating time of about 40 hours without the Z3210, or about 35 hours with the Bluetooth adapter installed and wireless communication enabled. It is ready for use immediately after power on, with no zero adjustment required. The supplied reference loop allows a quick functional check before measurement. Like all HIOKI current measuring instruments, the FT6380-50 was developed in Japan and is manufactured at HIOKI’s own production facilities in Japan.