Sonel – MPI-502 Loop Impedance & RCD Tester

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Datasheet - SONEL MPI-502


The MPI-502 from Sonel is a multifunction earth loop impedance and RCD tester combination in one compact unit, making it possible to test both loop impedance and RCD trip time and current without the need for separate instruments. Housed in the same ergonomic case as the MZC-304 loop impedance tester and the MRP-201 RCD tester, the MPI-502 offers the combined functions of these meters in one hand held, easy to operate instrument.

The user can test earth loop impedance up to 2000 Ohms over three ranges, with a resolution as low as 0.01 Ohm. Additionally RCD mode can be selected for loop impedance measurements. In this mode a lower 15mA test current is used, which prevents tripping of any RCD >30mA. Testing can be performed either with the supplied probes, or by use of the plug adapter, supplied as standard with the Sonel MPI-502 tester. Measurements can be taken on a wide range of electrical networks, with rated voltage 220/380V, 230/400V, 240/415V, and frequency between 45 and 65Hz. The MPI 502 can operate at voltages between 100 and 264V (L-N and L-E) and 100 and 440V (L-L). The user can select to test using either the non-trip method, or alternatively, a high current (23A for single phase and 44A for multi-phase circuits) can be utilsed at the operator’s discretion.

The Sonel MPI-502 can test operation of both general and selective RCD’s for rated currents of 10, 30, 100, 300 and 500mA, and can measure both tripping current and tripping time to a 1ms accuracy. For testing of trip time, the MPI-502 has the ability to use 50, 100, 200, and 500% of the RCD’s nominal rated current. For tripping current, the Sonel MPI-502 can apply a slowly rising ramp current from 30% of the RCD’s rated current, and will increase this current to the point of tripping, where the RCD trip current is recorded, which is particularly useful for testing of nuisance tripping circuit breakers. Both sine waveform and unidirectional pulsating residula current can be selected for testing, and measurements can be started from the positive or negative half of the forced leaking current. The MPI-502 RCD tester works from 180 up to 270V.

An AUTO function is built in to the instrument, and can be selected using the rotary dial. In this mode, the MPI-502 will measure earth loop impedance with a 15mA test current (to avoid tripping of the RCD >30mA) and will sequentially measure both trip current and trip time of the RCD, with only one trip occurring, cutting down on user time and complex set up.

  • Short circuit loop parameters measurements:
    • measurements of short circuit loop impedance in networks with rated voltage: 220/380 V, 230 V/400 V, 240/415 V and frequency 45…65 Hz,
    • measurements of short circuit loop impedance with current 15 mA without tripping the circuit breaker.

    Testing the RCD breakers of AC, A types:

    • testing of prompt, short-delay (general) and selective RCDs for the rated current values 10, 30, 100, 300, 500 mA,
    • IA measurement
    • RE and UB measurement without tripping the circuit breaker,
    • extended RCD test function AUTO, with measurement of ZL-PE with current 15 mA – measurement of IA and tA during one RCD tripping.

    Detection of the replacement L and N in the socket and automatic conversion in the meter.
    Low voltage resistance measurements of protective circuits and junctions:

    • measurement of resistance with ±200 mA current
    • calibration of test leads – possibility of using any length of test leads,
    • low current resistance measurement with accoustic signalling

    Rapid check for the correct connection of PE wire using touch electrode.
    Measurement of mains voltage and frequency.
    Power supply from LR6 batteries or NiMH accumulators (option).
    The device meets the requirements of IEC 61557 standard.

    MPI-502 is equipment to perform complete test and verify on electrical installations according to the most common safety standards (IEC 61557, VDE 0100, BS7671).