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Index: WMGBMRU30
Earth Resistance and Resistivity Meter
Technical Specification
  • Description

    Universal earth tester

    The Sonel MRU-30 compact earth resistance and soil resistivity meter enables efficient and easy earth resistance measurement. Many measurement methods available in a small casing.

    The MRU-30 meter is surprisingly versatile in nature. The instrument can be used to perform single earthing measurements as well as multiple earthing measurements using additional clamps or electrodes. Additional capabilities of this handy device include measurement of soil resistivity using the Wenner method, as well as verification of the continuity of equalising connections and protective conductors. Another advantage of the Sonel MRU-30 meter is the clear transmission of information alerting the user to possible dangers or detected irregularities. Information appears on the screen both before and after the test.

    Measurement methods

    • 3-pole and 4-wire method – measurement of earthing systems using auxiliary probes
    • 3-pole method with clamp – measurement of earthing systems with multiple earth electrodes
    • Two-clamp method – measurement of earthing system when the auxiliary probes cannot be used
    • Earth resistivity – Wenner method
    • Resistance of earth connection and equipotential bonding measured using current ≥200 mA with auto-zero function – meets the requirements of EN 61557-4


    • Measurement of auxiliary electrode resistances RS and RH 
    • Measurement of interference voltage
    • Measurement in the presence of interference voltages in networks with frequencies of 50 Hz and 60 Hz
    • Selection of maximum measurement voltage (25 V and 50 V)
    • In ground resistivity measurements, distances between electrodes can be input in meters (m) or feet (ft)


    The MRU-30 earth resistance meter is designed to measure single and multiple earthings using auxiliary electrodes and/or clamps. Moreover it is possible to measure ground resistivity (Wenner method) and verify the continuity of equipotential bondings and protective conductors.


    The meter provides the ability to make grounding tests with all kinds of the technical method. High immunity to interference allows it to be used even in difficult conditions in circuits with interfering currents. Simple and intuitive operation makes the measurements easier and faster. The meter has internal memory. The measurement results can be transmitted to a computer for data processing and preparation of documentation from the grounding tests.

    Durable and practical casing

    Ergonomic, small and practical housing allows comfortable and easy operation. The meter is resistant to all weather conditions. IP65 ingress protection guarantees dustproof and resistance to water jets on each side. The battery is permanently built-in and can be charged from a PowerBank or car cigarette lighter.

  • Technical Specification
    Measurement functions Measurement range Display range Resolution Accuracy
    Interference voltage 0 V…100 V 0 V…100 V 1 V ±(5% m.v. + 2 digits)
    Resistance of earth connection and equipotential bonding 0.13 Ω…1999 Ω acc. to EN 61557-4 0,00 Ω…1999 Ω from 0.01 Ω ±(2% m.v. + 3 digits)
    Earth resistance
    2-pole method 0.00 Ω…9999 Ω 0.00 Ω…9999 Ω from 0.01 Ω from ±(3% m.v. + 3 digits)
    3-pole and 4-wire method 0.53 Ω…9999 Ω acc. to EN 61557-5 0.00…9999 Ω from 0.01 Ω from ±(3% m.v. + 3 digits)
    3-pole + clamp method 0.00 Ω…9999 Ω 0.00 Ω…9999 Ω from 0.01 Ω from ±(3% m.v. + 3 digits)
    two-clamp method 0.00 Ω…99.9 Ω 0.00 Ω…99.9 Ω from 0.01 Ω from ±(10% m.v. + 8 digits)
    auxiliary electrodes resistance 0 Ω…19.9 kΩ 0 Ω…19.9 kΩ from 1 Ω ±(5% (RE +RH+RS) + 8 digits)
    Earth resistivity 0.0 Ωm…999 kΩm 0.0 Ωm…999 kΩm from0.1 Ωm Depends on the accuracy of the RE 4p measurement, but not less than ±1 digit
    Leakage current 0.0 mA…5.00 A 0.0 mA…5.00 A from 0.1 mA from ±(5% m.v. + 5 digits)

    “m.v.” - measured value

  • Files

Optional accessories

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