Hioki FT6380-50 Clamp On Earth Tester for Faster Multi-Grounded System Testing
For electricians, utility teams, and facility maintenance professionals, ground resistance testing can be time-consuming when conventional methods require auxiliary rods or disconnecting the ground conductor. The Hioki FT6380-50 Clamp On Earth Tester is designed to simplify that process by allowing users to measure grounding resistance on multi-grounded systems simply by clamping around the ground conductor. Hioki describes the FT6380-50 as a clamp-on earth tester that does not require an auxiliary grounding rod and does not require disconnecting the ground wire from the grounding rod, making it especially practical for field troubleshooting and routine inspection.
One of the FT6380-50’s biggest advantages is ease of use in multi-grounded systems. Hioki explains that the instrument has two cores: one for voltage injection and one for current measurement. From the defined voltage and measured current, it calculates the total circuit loop resistance. In typical multi-grounded systems, the parallel resistance of the surrounding grounding network is small enough to be ignored, which allows the measured value to approximate the target grounding resistance. This method helps users check grounding condition without the setup complexity of traditional earth resistance testing.
The FT6380-50 is also designed for tight installation spaces. Hioki highlights its dramatically slim 20 mm jaw thickness, describing it as a super-slim jaw that lets users clamp at the narrowest point more easily. For crowded grounding conductors, panel areas, and facility installations where access is limited, this compact clamp design is a practical benefit that can improve both speed and usability.
Another major strength is the ability to measure both earth resistance and AC current. Hioki states that the FT6380-50 measures earth resistance from 0.20 Ω to 1600 Ω and also measures AC current from 20.00 mA to 60.0 A. This means the instrument can support both grounding checks and current measurements ranging from very small leakage current to normal load current, giving technicians more flexibility from a single handheld device.
For users focused on leakage current, the meter offers especially high sensitivity. Hioki highlights 0.01 mA resolution on the 20.00 mA range, helping technicians measure low leakage current with greater certainty. At the same time, the instrument can handle 100 A AC continuous current input in measurement mode and up to 200 A AC for 2 minutes or shorter under the stated conditions, making it more versatile for maintenance applications where both leakage and higher current levels may need to be checked.
The FT6380-50 also includes field-friendly data features. Hioki states that the instrument can store up to 2,000 data points, and when used with the optional Wireless Adapter Z3210, measurement data can be transferred to smartphones or tablets using the GENNECT Cross app or directly into Excel files. Hioki also notes that the app can create reports, place measured values on photos, and display current harmonic levels up to the 30th order, along with content factor and total harmonic distortion ratio. That adds useful reporting and analysis capability beyond the basic handheld measurement itself.
Another practical feature is the built-in alarm function, which can provide both audible and visual notification when resistance or current exceeds a set threshold. The instrument also includes backlight, data hold, filter, and auto power save functions, helping support efficient field use in a range of lighting and operating conditions. Hioki lists a 40-hour continuous operating time without the wireless adapter and 35 hours with the adapter and wireless communication enabled.
In terms of ruggedness and safety, the FT6380-50 is rated CAT IV 600 V and supports a maximum rated terminal-to-ground voltage of 600 VAC, with anticipated transient overvoltage of 8000 V. It has IP40 protection with jaws closed, a maximum measurable conductor diameter of 32 mm, and weighs about 620 g. These details make it well suited for practical field use while preserving the safety level expected for work around live and grounded electrical systems.
It is important to note, however, that the FT6380-50 is intended specifically for multi-grounded systems. Hioki explicitly states that the larger the number of grounding poles in the system, the more accurate the measured value. So while this clamp-on approach is extremely convenient, it is best matched to the right kind of grounding network rather than every possible earthing scenario.
For utilities, industrial facilities, and field maintenance teams looking for a faster and less intrusive way to test grounding systems, the Hioki FT6380-50 offers a strong combination of clamp-on convenience, multi-grounded earth resistance measurement, leakage current sensitivity, and digital workflow support. Its slim jaw design and no-disconnection testing method make it a particularly practical tool for modern grounding system maintenance.
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