Earth Resistance and Resistivity Meters MRU 200

It allows to take the measurements of:

• earthing resistance using auxiliary electrodes,
• earthing resistance using auxiliary electrodes and clamp (for measurements of multiple earthing)
• earthing resistance using double clamps (for measurement of earthing when it is impossible to use auxiliary electrodes),
• impulse earth resistance (without disconnecting measured earthing),    
• ground resistivity (Wenner method),
• current using the clamp (e.g. leakage) and flexible clamp (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 200mA.

Additionally:

• measurement of resistance of auxiliary electrodes R_S and R_H,
• 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, 50Hz, 60Hz and 400Hz (with automatic selection of proper frequency of measuring signal or with manual selection),
• selection of maximum measuring voltage (25V and 50V)
• 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 300V acc. to EN 61010-1
• protection class acc. to EN 60529: IP54

Rated operational conditions:

• operation temperature: -10...+50°C
• storage temperature: -20...+70°C
• humidity: 20...80%

Other technical data:

• LCD display: graphic, backlighted
• interface: USB
• number of measurements carried out of set of batteries: > 1200
• warranty: 36 months

Measurement of interference voltage

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

Measurement of interference frequency

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

Measurement of earthing resistance (method 3- and 4-pole)

measurement range to IEC61557-5: 0,100Ω...19,9kΩ

Range	Resolution	Accuracy
0,000...3,999Ω	0,001Ω	±(2% m.v. + 4 digits)
4,00...39,99Ω	0,01Ω	±(2% m.v. + 2 digits)
40,0...399,9Ω	0,1Ω
400...3999Ω	0,001kΩ
4,00k...19,99kΩ	0,01kΩ	±(5% m.v. + 2 digits)

Measurement of continuity of equipotential bondings and protective conductors (R_cont)

measurement range to IEC61557-4: 0,045Ω...19,99kΩ

Range	Resolution	Accuracy
0,000...3,999Ω	0,001Ω	±(2%  m.v. + 4 digits)
4,00...39,99Ω	0,01Ω	±(2% m.v. + 2 digits)
40,0...399,9Ω	0,1Ω
400...3999Ω	0,001kΩ
4,00k...19,99kΩ	0,01kΩ	±(5% m.v. + 2 digits)

Measurement of resistance of auxiliary electrodes R_H and R_S

Range	Range	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) measurement range to IEC61557-5: 0,120Ω...1,99kΩ

Range	Resolution	Accuracy
0,000...3,999Ω*	0,01Ω	±(8%  m.v. + 4 digits)
10,0...99,9Ω	0,01Ω	±(8% m.v. + 3 digits)
100...999Ω	0,1Ω
1,00k...1,99kΩ	1Ω

* in range 0,000…0,045Ω the accuracy is not specified.

Measurement of multiple earthing resistance with using double clamps

Range	Resolution	Accuracy
0,00...19,99Ω	0,1Ω	±(10% m.v. + 3 digits)
20,0...149,9Ω	0,1Ω	±(20% m.v. + 3 digits)

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

Range	Resolution	Accuracy
0,0...199,9Ωm	0,1Ωm	depending on measurement accuracy RE with 4p method, but not less than ±1 digit
200...1999Ωm	1Ωm
2,00k...19,99kΩm	0,01kΩm
20,0k...99,9kΩm	0,1kΩm
100k...999kΩm	1kΩm

L – distance between probes: 1...50m

Measurement of AC current (leakage)

Range	Resolution	Accuracy
0,1...99,9mA 1	0,1mA	±(8% m.v. + 5 digits)
100...999mA 1	1mA	±(8% m.v. + 3 digits)
1,00...4,99A 1,2	0,01A	±(5% m.v. + 5 digits)1 unspecified 2
5,00...9,99A 1,2	0,01A	±(5% m.v. + 5 digits)
10,0...99,9A 1,2	0,1A
100...300A 1,2	1A

¹ – receiving clamp  (diameter 52mm) – C-3
² – flexible clamp (Rogowsky coil) with diameter 400 mm – F-1

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

Range	Resolution	Accuracy
0,0...99,9Ω	0,1Ω	±(2,5%  m.v. + 3 digits)
100...199Ω	1Ω

choice impulse edges:  4/10ms,  10/350ms

„m.v.”- measured value