MRU-200 GPS Earth Resistance and Resistivity Meter

MRU-200 is the only meter in the market which uses all measurement methods.

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Multiple measurement possibilities: 

• earth resistance using auxiliary electrodes,


• earth resistance using auxiliary electrodes and current clamp for measurements of multiple earth ground points


• earth resistance using double current clamps for measurement of earth ground when it is impossible to use  electrodes in the ground


• impulse earth impedance for lightning without disconnecting measured earthing


• ground resistivity (Wenner method),


• current using current clamp (e.g. leakage) and flexible current probe (Rogowsky coil),


• measurement of continuity of equipotential bondings and protective conductors (meeting the requirements of IEC 60364 - 6 - 61:2000 section 6.12.2) with auto-zero function – with current 200 mA.

Additionally:

• measurement of resistance of auxiliary electrodes RS and RH,


• measurement of interference voltage,


• measurement of interference frequency,


• measurement in the presence of interference voltage in the power network
  with frequency 16 2/3 Hz, 50 Hz, 60 Hz and 400 Hz (with automatic selection of proper frequency of measuring signal or with manual selection),


• selection of maximum measuring voltage (25 V and 50 V)


• introducing the distance between the electrodes for the resistivity in metres (m) and feet (ft),


• memory of 990 measurements (10 banks of 99 cells each),


• calibration of clamp used,


• real time clock (RTC),


• data transmission to the computer (USB),


• indication of battery state.

Electric security:

• type of insulation: double, according to EN 61010 - 1 and IEC 61557


• measurement category: CAT IV 300 V acc. to EN 61010 - 1


• protection class acc. to EN 60529: IP54

Rated operational conditions:

• operation temperature: 14F to 122F / -10 to +50°C


• storage temperature: -4F to 158F / -20 to +70°C


• humidity: 20 to 80%

Other technical data:

• LCD display: graphic, backlighted


• interface: USB


• number of measurements carried out of set of batteries: > 1200


• warranty: 24 months

Measurement of interference voltage

Range	Resolution	Accuracy
0 to 100 V	1 V	±(2% m.v. + 3 digits)

Measurement of interference frequency

Range	Resolution	Accuracy
15 to 450 Hz	1 Hz	±(1% m.v. + 2 digits)

Measurement of earthing resistance (method 3- and 4-pole)
measurement range to IEC61557 - 5: 0.100 Ω to 19.9 kΩ

Range	Resolution	Accuracy
0.000 to 3.999 Ω	0.001 Ω	±(2% m.v. + 4 digits)
4.00 to 39.99 Ω	0.01 Ω	±(2% m.v. + 2 digits)
40.0 to 399.9 Ω	0.1 Ω
400 to 3,999 Ω	0.001 kΩ
4.00k to 19.99 kΩ	0.01 kΩ	±(5% m.v. + 2 digits)

Measurement of continuity of equipotential bondings and protective conductors (Rcont)
measurement range to IEC61557 - 4: 0.045 Ω to 19.99 kΩ

Range	Resolution	Accuracy
0.000 to 3.999 Ω	0.001 Ω	±(2% m.v. + 4 digits)
4.00 to 39.99 Ω	0.01 Ω	±(2% m.v. + 2 digits)
40.0 to 399.9 Ω	0.1 Ω
400 to 3,999 Ω	0.001 kΩ
4.00k to 19.99 kΩ	0.01 kΩ	±(5% m.v. + 2 digits)

Measurement of resistance of auxiliary electrodes RH and RS

Range	Range	Accuracy
0 to 999 Ω	1 Ω	±(5% (RS+RE+RH) + 8 digits)
1.00k to 9.99 kΩ	0.01 kΩ
10.0k to 19.9 kΩ	0.1 kΩ

 

Measurement of multiple earthing resistance with using the clamp and auxiliary
electrodes (3p + clamp)

Range	Resolution	Accuracy
0.000 to 3.999 Ω*	0.01 Ω	±(8% m.v. + 4 digits)
10.0 to 99.9 Ω	0.01 Ω	±(8% m.v. + 3 digits)
100 to 999 Ω	0.1 Ω
1.00k to 1.99 kΩ	1 Ω

* - in range 0.000 to 0.045 Ω the accuracy is not specified.

Measurement of multiple earthing resistance with using double clamps

Range	Resolution	Accuracy
0.00 to 19.99 Ω	0.1 Ω	±(10% m.v. + 3 digits)
20.0 to 149.9 Ω	0.1 Ω	±(20% m.v. + 3 digits)

Measurement of ground resistivity Measurement method: Wennera, ρ=2πLRE

Range	Resolution	Accuracy
0.0 to 199.9 Ωm	0.1 Ωm	depending on measurement accuracy RE with 4p method, but not less than ±1 digit
200 to 1999 Ωm	1 Ωm
2.00k to 19.99 kΩm	0.01 kΩm
20.0k to 99.9 kΩm	0.1 kΩm
100k to 999 kΩm	1 kΩm

L – distance between probes: 1 to 150 ft / 1 to 50 m
Measurement of AC current (leakage)

Range	Resolution	Accuracy
0.1 to 99.9 mA 1	0.1 mA	±(8% m.v. + 5 digits)
100 to 999 mA 1	1 mA	±(8% m.v. + 3 digits)
1.00 to 4.99 A 1,2	0.01 A	±(5% m.v. + 5 digits)1 unspecified 2
5.00 to 9.99 A 1,2	0.01 A	±(5% m.v. + 5 digits)
10.0 to 99.9 A 1,2	0.1 A
100 to 300 A 1,2	1 A

1 – receiving clamp (diameter 2" / 52 mm) – C-3
2 – flexible clamp (Rogowsky coil): F-1 diameter 14" / 360 mm; F-2: diameter 9" / 235 mm; F-3: diameter 4.7" / 120 mm

Measurement of dynamic earthing resistance (RD) with impulse wave method (4p )

Range	Resolution	Accuracy
0.0 to 99.9 Ω	0.1 Ω	±(2,5% m.v. + 3 digits)
100 to 199 Ω	1 Ω

choice impulse edges: 4/10μs, 8/20μs, 10/350μs

„m.v.”- measured value