FT6041 - Multi-function Earth Tester for 4-Pole Measurement and Soil Resistivity

Key Specifications

• Earth resistance measurement: 2-pole, 3-pole and 4-pole 
• Soil resistivity measurement with 4-pole Wenner method
• Separate 4-terminal resistance measurement 
• Expandable for selective and stakeless earth resistance measurement 
• Optional Bluetooth communication with Z3210 

Typical Applications

• Earth resistance measurement in electrical installations and grounding systems
• Soil resistivity measurement according to Wenner for grounding design and site surveys 
• Continuity and resistance measurement between earth electrodes and installations
• Selective earth resistance measurement with optional CT9848
• Stakeless earth resistance measurement with optional FT9847 and CT9848 

Detailed Product Overview  

The HIOKI FT6041 is an earth resistance meter for electrical professionals working in service, maintenance, inspection and grounding design. It combines 2-pole, 3-pole and 4- pole earth resistance measurement with soil resistivity measurement and separate 4-terminal resistance measurement in one instrument. With optional accessories, it can also be expanded for selective earth resistance measurement, which HIOKI refers to as Measuring Earth with a Clamp (MEC), as well as for stakeless earth resistance measurement. 

The multi functional earth tester is rated IP67 for dust and water protection and is supplied with test leads on reels, auxiliary earth spikes, earth nets modules, a carrying case and a tote bag. This means it is equipped for conventional earth resistance measurement with auxiliary earth spikes as well as for measurements on concrete and other hard surfaces. Selective and stakeless earth resistance measurement can be added with the optional CT9848 and FT9847 clamps. 

Measurement methods for earth resistance and soil resistivity 

The 3-pole method is used on the FT6041 for precise verification of the earth resistance of an existing earth electrode. It requires two auxiliary earth spikes, and the earth electrode under test must be disconnected from the installation for measurement. In very wet conditions, the test voltage can be reduced from 30 V to 20 V. When a full 3-pole setup is not possible or not practical, a simplified 2-pole method is available instead. For 2-pole measurement, the selectable test voltages are 8 V and 20 V. The measurement frequency can also be set to 94 Hz, 105 Hz, 111 Hz, 128 Hz or 55 Hz to respond to site conditions or reduce the influence of noise. 

For determining soil resistivity, the FT6041 provides 4-pole measurement according to the Wenner method. The instrument first measures a resistance value and then calculates soil resistivity in Ω·m from the selected electrode spacing. In 4-pole measurement, the test voltage can also be switched between 30 V and 20 V. Electrode spacing can be set from 1 m to 50 m in 0.1 m steps, or from 3 ft to 160 ft in 1 ft steps.

Selective and stakeless measurement with clamps 

For selective earth resistance measurement, the FT6041 can be expanded with the optional CT9848 Signal Detection Clamp. This method is intended for multiple earthed installations where the resistance of a specific earth electrode needs to be measured without disconnecting it from the installation. HIOKI refers to this method as Measuring Earth with a Clamp, or MEC. Depending on the measurement task, it is available as a 3-pole method with clamp or a 4-pole method with clamp. 

For stakeless earth resistance measurement, the CT9848 is used in combination with the optional FT9847 Signal Induction Clamp. The FT9847 injects the test signal into the grounding conductor, while the CT9848 senses the resulting current. This two clamp method is intended for multiple earthed systems and does not require auxiliary earth spikes. It is used for earth resistance measurement in installations where auxiliary earth spikes cannot or should not be used. 

Resistance measurement and measurements on hard surfaces 

In addition to its earth testing functions, the FT6041 also provides separate 2-terminal and 4- terminal resistance measurement. This is useful, for example, when an earth electrode has been disconnected from the installation for a 3-pole test and the connection needs to be checked after reconnection. The 2-terminal method is suitable for simple continuity checks, while the 4-terminal method reduces the influence of lead resistance and allows more precise low-resistance measurements on earth connections. This means a separate resistance meter is not required. 

The FT6041 includes two L9846 Earth Nets Modules. They are used when earth spikes cannot be inserted directly into concrete or other hard surfaces. Once opened, the modules provide two copper mesh contact areas that are placed on the surface to be tested and moistened with water to establish electrical contact. The earth nets modules can be clicked onto the supplied test lead reels, forming a single unit with them.

Bluetooth communication with Z3210 

Optional Bluetooth communication can be added with the Z3210 Bluetooth Adapter. This allows measured values to 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 other input based software. 

Like all HIOKI earth testers, the FT6041 was developed in Japan and is manufactured at HIOKI’s own production facilities in Japan