MRU-20

It allows to take:

• earth resistance measurement using auxiliary probes with 3-pole method,
• resistance measurement using 2-pole method,
• measurement of continuity of equipotential bondings and protective conductors (meeting the requirements of IEC 61557 - 4) with auto-zero function – with current 200 mA.

Additionally:

• AUTO-OFF function after 5 minutes,
• indication of battery state.

Measurement of earthing resistance
measurement range to IEC61557 - 5:

• 0,50 Ω...1,99 kΩ U_n=50 V;
• 0,68 Ω...1,99 kΩ dla U_n=25 V

Range	Resolution	Accuracy
0,00...9,99 Ω	0,01 Ω	±(2% m.v. + 3 digits)
10,0...99,9 Ω	0,1 Ω
100...999 Ω	1 Ω
1,00...1,99 kΩ	0,01 kΩ

• measurement current: under short circuit >20 mA,
• voltage on open terminals: selectable 25 V AC or 50 V AC,
• frequency of measurement current: 125 Hz

Measurement of resistance of auxiliary electrodes R_H i R_S

Range	Resolution	Accuracy
0...999 Ω	1 Ω	±(5% (RS+RE+RH) + 3 digits)
1,00k...9,99 kΩ	0,01 kΩ
10,0k...50,0 kΩ	0,1 kΩ

Measurement of interference voltage U_N (RMS)

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

Measuremet of continuity of equipotential bondings and protective conductors
measurement range to IEC61557 - 4: 0,13...199 Ω

Range	Resolution	Accuracy
0,00...9,99 Ω	0,01 Ω	±(2% m.v. + 3 digits)
10,0...99,9 Ω	0,1 Ω
100...199 Ω	1 Ω

• measuring method: technical 2-pole method,
• max. voltage on open terminals: 13 V,
• measurement current: under short circuit >200 mA,
• auto-zero function for measurement leads0,13 Ω...199 Ω

Electric security:

• type of insulation: double, according to IEC 61010 - 1and IEC 61557
• measurement category: CAT IV 300 V acc. to IEC 61010 - 1
• protection class acc. to EN 60529: IP54

Rated operational conditions:

• operation temperature: -10...+55°C
• storage temperature: -20...+70°C
• humidity: 20...80%

Other technical data:

• power supply: alkaline batteries or NiMH rechargeable batteries, size AA (8 pcs)
• LCD display: segment, backlit
• weight with batteries: approx. 1,3 kg
• dimensions: 260 x 190 x 60 mm
• electromagnetic compatibility: according to IEC 61000 - 6 - 3 and IEC 61000 - 6 - 2