FT6031-50 - Earth Tester for 2-Pole and 3-Pole Measurement

Key Specifications

• 2-pole and 3-pole earth resistance measurement 
• Automatic interference voltage and auxiliary earth resistance check 
• IP67 dustproof and waterproof 
• Optional Bluetooth communication 

Typical Applications

• Grounding system inspection in electrical installations
• Verification of existing earth electrodes during maintenance and periodic testing
• On-site earth resistance testing in outdoor environments 

Detailed Product Overview  

The HIOKI FT6031-50 is an earth tester for electrical professionals working in service, maintenance and inspection. It supports 3-pole measurement for precise earth resistance testing as well as a simplified 2-pole method using an existing reference earth when a full setup with auxiliary earth spikes is not possible. Optional Bluetooth communication can be added. 

2-pole and 3-pole earth resistance measurement 

The 3-pole method is used to check the earth resistance of an existing earth electrode in buildings and electrical installations. For this measurement, the earth electrode under test is disconnected from the installation and measured together with two auxiliary earth spikes. The required test leads and auxiliary earth spikes are included with the FT6031-50 and are dimensioned for the typical setup with 10 m and 20 m lead lengths. Measurement is performed at 128 Hz ±2 Hz, with an output voltage of 30 V rms or less and a measurement current of 25 mA rms or less. A measurement typically takes up to 6 s, including the automatic check of interference voltage and auxiliary earth resistance. 

The 2-pole method provides a simplified earth resistance measurement when a full 3-pole setup with two auxiliary earth spikes is not possible or not practical. In this case, an existing low-resistance earth is used as a reference, typically the neutral side of a grounded power supply. The measured value therefore includes not only the resistance of the earth electrode under test, but the sum of the test earth and the reference earth. The measurement current is limited to 4 mA rms or less, so under suitable installation conditions a residual current device will typically not trip. The 2-pole method is therefore intended for simplified checks rather than for the most precise measurement of a single earth electrode.

Instrument functions and accessories

The FT6031-50 supports earth resistance measurement with automatic pre-checks, lead compensation and threshold evaluation. Before the actual measurement starts, the instrument automatically checks interference voltage, meaning any voltage already present on the earth electrode, as well as the resistance of the auxiliary earth spikes. The zeroadjustment function compensates for the influence of test lead resistance. The comparator function allows direct PASS/FAIL evaluation against a preset threshold. A continuous measurement mode is also available so that changes in the reading can be observed directly while positioning or repositioning the auxiliary earth spikes. 

Optional longer test leads such as the L9843-51 and L9843-52 are available for setups with greater distances. On concrete or other hard surfaces where auxiliary earth spikes cannot be inserted directly, 9050 Earth Nets or L9846 Earth Nets Modules can be used. The earth nets modules can be clicked onto the supplied L9842-11 and L9842-22 lead reels as well as the separately available L9845-31, L9845-33 and L9845-52 lead reels, forming a single unit with them. 

Optional Bluetooth Communication

Optional Bluetooth communication can be added to the FT6031-50 with the Z3210 Bluetooth Adapter. Measured values can then be transferred wirelessly to Windows, iOS or Android devices. For smartphones and tablets, the free GENNECT Cross app is available for displaying, storing and documenting readings. Alternatively, the Z3210 can operate in HID mode, where measured values are sent to the active application as keyboard input. This allows direct data entry into Excel, text applications or custom software applications. 

Like all HIOKI earth testers, the FT6031-50 was developed in Japan and is manufactured at HIOKI’s own production facilities in Japan.