MRU-120 HD Earthing resistance and soil resistivity meter
Measuring grounding and specific ground resistance under the toughest conditions
The Sonel MRU-120HD grounding and specific ground resistance measuring device is a robust and functional tool that can be used in particularly difficult working conditions. It is not affected by dust or mud and also proves its worth in areas where there is an increased risk of splashing water.
The Sonel MRU-120HD measuring device can be used to measure grounding resistance using the 3-pole and 4-wire methods. The device can also be used to take measurements with additional clamps (multiple grounding without having to disconnect the control terminals) and with the two-clamp method. In certain cases, measurements can be performed without the use of auxiliary probes driven into the ground. The Sonel MRU-120HD is a tool that has proven itself particularly useful for grounding measurements in the energy sector. The measuring range (for measurements according to EN 61557) starts at 0.30 Ω.
Other practical functions of the device include the ability to measure the specific earth resistance and the continuity of protective and equipotential bonding connections.
Measurement methods:
- 3-pole and 4-wire method – earth measurement with auxiliary probes
- 3-pole method with clamp – measurement of multiple earths
- Two-clamp method – earth measurement when auxiliary probes cannot be used
- Specific earth resistance – Wenner method
- Resistance of grounding and equipotential bonding conductors with ≥200 mA test current. Automatic zeroing of the measuring cables – meets the requirements of EN 61557-4
Additional functions:
- Excellent resistance to harsh environmental conditions – the transport case protects against dust and water ingress and protects against damage from falls
- Measurement of the resistance of the RS and RH auxiliary probes
- Measurement of interference voltages
- Frequency measurement of interference signals
- Measurement under the influence of interference voltages caused by supply lines in power grids with frequencies of 50 Hz and 60 Hz
- Selection of the max. measurement voltage (25 V and 50 V)
- When measuring the specific earth resistance, the distances between the electrodes can be entered in meters (m) or feet (ft)
- Memory for 990 measurements (10 banks of 99 cells each)
- Calibration function for clamps
- Real-time clock (RTC)
- Data transfer to PC
- Battery charge status display
Areas of application:
The MRU-120HD measuring device was developed for the toughest operating conditions. It generates a test current of over 200 mA, enabling effective measurement of the grounding of substations and power plants.
The use of clamps means that it is not necessary to disconnect any connections. This is particularly important when working on objects that are exposed to severe weather conditions and where the connecting elements are sometimes corroded or rusted. The graphical user interface displays clear results and unambiguous messages. This enables fast and effective use.
Transport and safety:
t doesn't matter whether you are taking measurements in mud or sand amid clouds of dust. The MRU-120HD measuring device is always ready for use. The IP67 protection rating with the cover closed ensures dust tightness and prevents water ingress – even if the housing is briefly submerged! During measurement, the protection class remains high (IP54) and offers protection against dust and splash water from all directions.
Features:
The measurement methods available in the device enable comprehensive control of the working and protective earthing. The calibration function of the measuring cables eliminates the influence of their resistance on the result. But that's not all.
- The 4-wire method enables very accurate measurement of the very low resistance values to be expected.
- The measuring cables connected to the grounding system have no influence on the measurement result achieved here.
- The measurement of the resistance of the ground connection and the equipotential bonding with a current of more than 200 mA meets the requirements of the EN 61557-4 standard.
- Before the measurement, the meter checks for excessive interference voltage, which may be an indication of further irregularities.
Memory and results:
The results can be stored in the device's memory. This is divided into 10 banks with 99 cells each, with each cell corresponding to one measurement. These results can be easily transferred to the Sonel Reader software for archiving or later analysis.
