MRU-120

Possible measurements:

It allows to take the measurements of:

• earth resistance using auxiliary electrodes,
• earth resistance using auxiliary electrodes and clamp (for measurements of multiple earth)
• earth resistance using double clamps (for measurement of earthing when it is impossible to use auxiliary electrodes),
• ground resistivity (Wenner method),
• 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 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 50 Hz, 60 Hz
• selection of maximum measuring voltage (25 V and 50 V)
• introducing the distance between the electrodes for the resistivity in metres (m),
• memory of 990 measurements (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.

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

Other technical data:

• LCD display: graphic, backlighted
• interface: USB, wireless
• number of measurements carried out of set of batteries: > 500
• warranty: 24 months

Measurement of interference voltage

• singnalling overvoltage 24 V or 40 V rms
• measurement for DC and AC 45…65 Hz,

Measurement of earth resistance (method 3- and 4-pole)
measurement range to IEC61557 – 5: 0,30 Ω…19,9 kΩ

• measurement current: under short circuit >200 mA,
• voltage on open terminals: selectable <25 V AC or <50 V AC,
• frequency of measurement current: 125 (for networks 50 Hz) or 150 Hz (for 60 Hz),

Measurement of continuity of equipotential bondings and protective conductors (Rcont)
measurement range to IEC61557 – 5: 0,24 Ω…19,9 kΩ

• voltage on open terminals: <24 Vrms but >4 Vrms,
• measurement current: under short circuit >200 mA,
• frequency of measurement current: 125 (for networks 50 Hz) or 150 Hz (for networks 60 Hz), possible choice of measurement frequency in menu,
• auto-zero function measurement leads

Measurement of resistance of auxiliary electrodes R_H and R_S

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

• voltage on open terminals: selectable <25 V AC or <50 V AC,
• measurement current: under short circuit > 200 mA,
• frequency of measurement current: 125 (for networks 50 Hz) or 150 Hz (for 60 Hz),

Measurement of multiple earth resistance with using double clamps

• frequency of measurement current 125 (for networks 50 Hz) or 150 Hz (for networks 60 Hz)

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

L – distance between probes: 1…50 m