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Fault Loop Impedance Meter
Technical Specification
  • Description

    Pocket measurements

    Simple and ergonomic short circuit loop impedance meter Sonel MZC-20E.

    The small MZC-20E meter allows for precise measurement of short circuit loop impedance in networks of different voltage ratings. With the use of this instrument, it is possible to test network voltage up to 440 V. The device is especially useful for installers and measuring engineers providing services in single- and multi-family buildings, office buildings, industrial plants and other buildings and facilities equipped with low-voltage electrical installations. The MZC-20E meter is also perfect for electrical maintenance services. Regardless of the area of application, in each case it guarantees smooth operation and high accuracy of the results obtained. A further advantage of this tool is its ability to operate in adverse environmental conditions, which is made possible by its very robust casing. Despite its compact dimensions, the meter performs its role flawlessly and serves well wherever precise and instant measurements are required.


    • Fault loop impedance measurement with 0.01 Ω resolution.
    • Operates in networks with voltages 220/380 V, 230/400 V, 240/415 V (operating range 180…440 V).
    • Operating frequency 45…65 Hz
    • Calculation of Ik fault current.
    • Automatic differentiation between phase and phase-to-phase voltage.
    • Possibility of applying test leads: 1.2 m, 5 m and longer.
    • Measurement with swapped L and N conductors.
    • Measurement of resistance (RS) and reactance (XS) components.

    Additional features

    • Voltage measurement 0...440 V AC.
    • Power supply: batteries (4 x LR6) or rechargeable batteries (4 x NiMH).


    This meter is designed for measurements on objects protected by circuit breakers with rating up to 63 A, where fault currents reach 1 kA, i.e. in housing industry, single and multi-family houses, office buildings, small factories and all other facilities that are equipped with low-voltage electrical systems. In addition, the meter is a useful tool for maintenance services.

  • Technical Specification
    Measurement functions Measurement range Display range Resolution Accuracy
    Voltage 0 V…440 V 0 V…440 V 1 V ±(2% m.v. + 2 digits)
    Short-circuit loop parameters
    2p method - standard current measurement maximum current 26.7 A from 0.24 Ω…200 Ω acc. to EN 61557 0.00 Ω…200 Ω from 0.01 Ω from ±(2.5% m.v. + 3 digits)
    Short-circuit current readings
    2p method - standard current measurement Calculated on the basis of test ZS ranges and rated voltages 1.15 A…40 kA from 0.01 A Calculated on the basis of error for fault loop

    “m.v.” - measured value

  • Files