MRU-120 Earth resistance and resistivity meter

MRU-120 meter is the most commonly used earth resistance measurement device. Tests can be performed using the 3-pole method and 4-pole method.

Manufacturer: SONEL S.A. (Poland).

Features

Earth resistance measurment with 3-pole,4-pole method
Selective earth resistance measurement with clamp (no influence from parallel earths; no opening of rusty junctions is needed)
Continuity of equipotential bondings and protecting conductors
Two clamps earth resistance measurement without auxiliary test probs
Earth resistivity measurement
Measurement of resistance of auxiliary electrodes Rs and Rh
Measurement of interference voltage and frequency
Measurement in the presence of interference voltage in the power network with frequency 50Hz , 60Hz
Selection of maximum measuring voltage (25V and 50V)
Introducing the distance between the electrodes for the resistivity in metres (m) or feet (ft)
Memory of 990 measurement results (10 banks of 99 cells each)
Calibration of clamp used
Real time clock (RTC)
Data transmission to the computer (USB, wireless)
Indication of battery state

Technical specifications

Measurement of interference voltage
Range	Resolution	Accuracy
0...100V	1V	±(2% m.v + 3 digits)
Measurement of continuity of equipotential bondings and protective conductors (Rcont) (0,24...19,9kΩ)
Range	Resolution	Accuracy
0,00...19,99Ω	0,01Ω	±(2% m.v. + 2 digits)
20,0...199,9Ω	0,1Ω
200...1999Ω	1Ω
2,0k...9,99kΩ	0,01kΩ	±(5% m.v. + 2 digits)
10,0k...19,9kΩ	0,1kΩ	±(5% m.v. + 2 digits)
Measurement of earthing resistance (method 3- and 4-pole) (0,30Ω...19,9kΩ)
Range	Resolution	Accuracy
0,00...19,99Ω	0,01Ω	±(2% m.v. + 2 digits)
20,0...199,9Ω	0,1Ω
200...1999Ω	1Ω
2,0k...9,99kΩ	0,01kΩ	±(5% m.v. + 4 digits)
10,0k...19,9kΩ	0,1kΩ	±(5% m.v. + 4 digits)
Measurement of resistance of auxiliary electrodes Rh and Rs
Range	Resolution	Accuracy
0...999Ω	1Ω	±(5% (Rs +Re +Rh) + 8 digits)
1,00k...9,99kΩ	0,01kΩ
10,0k...19,9kΩ	0,1kΩ
Measurement of multiple earthing resistance with using the clamp and auxiliary electrodes (3p + clamp) (0,44Ω...1999Ω)
Range	Resolution	Accuracy
0,00...19,99Ω	0,01Ω	±(8% w.m. + 3 digits)
20,0...199,9Ω	0,1Ω
200...1999Ω	1Ω
Measurement of multiple earthing resistance with using double clamps
Range	Resolution	Accuracy
0,00..19,99Ω	0,01Ω	±(10% m.v. + 3 digits)
20,0...149,9Ω	0,1Ω	±(20% m.v. + 3 digits)
Measurement of ground resistivity (Measurement method: Wenner, r=2pLRE)
Range	Resolution	Accuracy
0,0...199,9Ω	0,1Ω	depending on measurement accuracy Rе with 4p method, but not less than ±1 digit
200...1999Ω	1Ω
2,0k...19,99kΩ	0,01kΩ
20,0k...99,9kΩ	0,1kΩ
100k...999kΩm	1kΩ

Complete set

Standard accessories:

MRU-120
Test lead with banana plug; 1,2m; red
Test lead with banana plugs 2,2m; black
Test lead on a reel with banana plugs; 25m red
Test lead on a reel with banana plugs; 25m blue
Test lead on a reel with banana plugs; 50m yellow
USB transmission cable
Pin probe with banana plug; yellow
Earth contact test probe (rod); 0,30m
Carrying case L2
"Crocodile" clip K01; black
Power supply adaptor Z7
Cable for battery charger
Hanging straps

Optional accessories:

Earth contact test probe (rod); 0,80m
Test lead with banana plugs 2m (N-1)
Carrying case L3
Current clamp C-3 (Ø=52mm)
Current clamp N-1 (Ø=52mm)
Akumulator Ni-MH 4, 8V 4,2Ah
Battery case LR14 (size C)
USB radio interface
Crocodile” clip K02; red
Cramp
Software for creation of documentation from electrical measurements „SONEL PE4”
Charger for battery loading from the socket of car lighter (12V)

Documentation

MRU-120 Datasheet.pdf