HIOKI FT6380-90 - Ground Resistance Clamp with Bluetooth 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 
• Bluetooth communication included

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 FT6380-90 combines the FT6380-50 Earth Ground Clamp with Bluetooth communication in one package. It is designed for testing grounding systems with multiple parallel earth paths and 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 FT6380-90 uses a clamp head with two separate coils. One coil inductively couples a test voltage into the earth conductor inside the jaw, while the second 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 clamp provides 10 automatically selected ranges from 0.20 Ω to 1600 Ω. The lowest specified measurement value with stated accuracy is 20 mΩ. The displayed reading can be frozen with the HOLD key, and a switchable backlight supports work in low light conditions. This measurement method requires at least two parallel earth paths. 

Leakage current, load current and additional functions

In addition to checking the resistance of the earth connection, the clamp can also be used for AC current measurement. Its lowest current range starts at 20 mA, allowing small leakage currents to be detected, while load currents up to 60 A are also covered. Current is measured using a True RMS method. 

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

The clamp also includes a configurable threshold alarm that can be set separately for resistance measurement and current measurement. Readings from both functions can be stored in the internal memory, which holds up to 2000 readings.

Bluetooth communication 

Because the FT6380-90 includes the Z3210 Bluetooth Adapter as part of the set, readings can be transferred to smartphones, tablets or other compatible devices without additional accessories. Two operating modes are available: GENNECT Cross mode for communication with the GENNECT Cross app, and HID mode for direct output of readings to the active application. The two modes cannot be used at the same time. The selected mode is stored in the adapter. 

In GENNECT Cross mode, readings can be displayed, stored and documented on a mobile device. The app also supports linking readings with photos, maps and additional information from the measurement site. Measurement data stored in the instrument memory can be read out via GENNECT Cross. Data can be further processed in the app and exported as reports. GENNECT Cross is available free of charge for iOS and Android.

In HID mode, the clamp sends readings to the active application like a wireless keyboard. This allows values to be entered directly into Excel, text applications or input fields in custom software solutions without additional software. HID mode is supported on Windows, iOS and Android devices. 

Made in Japan 

Powered by two LR6 batteries, the FT6380-90 provides a typical operating time of about 40 hours with wireless communication disabled, or about 35 hours with 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 FT6380-90 was developed in Japan and is manufactured at HIOKI’s own production facilities in Japan.