IEC 61557-2-2019 pdf download.Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. – Equipment for testing, measuring or monitoring of protective measures – Part 2: Insulation resistance.
6 Tests
6.1 General
In addition to IEC 61 557-1 :201 9, Clause 6 and IEC 61 01 0-2-034:201 7, Clause 6, the following tests shall be performed.
6.2 Operating uncertainty
The maximum percentage operating uncertainty within the measurement range to be marked or stated shall not exceed ±30 % with the measured value as fiducial value, as determined in accordance with Table 1 .
The operating uncertainty shall apply under the rated operating conditions in accordance with
IEC 61 557-1 :
– nominal value of the supply voltage;
– nominal r/min when power is supplied by a hand-driven generator;
– reference temperature 23 °C ± 2 °C;
– reference position in accordance with the manufacturer’s statement.
6.3 Open-circuit voltage
The open-circuit voltage shall be checked with a test circuit with a loading resistance of a minimum of U N × 1 00 kΩ/V for compliance with the specification in 4.2 (routine test).
6.4 Rated current
The rated current shall be tested through a test resistor of a value of U N × 1 000 Ω/V.
Compliance with the requirements in 4.3 shall be checked (routine test).
6.5 Measuring current The measuring current shall be tested and compliance with the requirements in 4.4 shall be checked (routine test). When an AC voltage is superimposed on the DC voltage, the measuring equipment for measuring the peak value of the current shall be applied.
6.6 Overvoltage tests 6.6.1 Overvoltage tests with AC voltage The permissible overvoltage in accordance with 4.6 shall be tested. For this purpose an AC voltage according to 4.6 shall be applied for a duration of not less than 1 0 s whilst the equipment is switched on and off (type test). The AC test source shall have the capability to activate protective devices and to indicate weak points of circuitry. If protective devices are activated or parts are damaged, the test shall be repeated with a test source having a capability according to IEC 61 01 0-1 :201 0, 1 6.2. After the test with AC overvoltage according to 4.6, defects, if any, shall be clearly indicated; indications and displayed values shall not lead to unsafe interpretations. After tests with AC overvoltages according to 4.6, the equipment shall stay within the specification. This includes reactivation of protective devices by the user without any repair. The replacement of fuses accessible to the user should be considered as reactivation of a protective device. 6.6.2 Overvoltage tests with DC voltage In addition to the overvoltage tests with AC, a DC voltage of 1 ,2 times the magnitude of the highest rated output voltage stored on a capacitor of 2 µF shall be applied in both polarities whilst the equipment is switched on and off. After this, the measuring equipment shall stay within the specification, but without activation of the protective devices (type test).
6.7 Battery life in battery operated instruments The number of possible measurements shall be determined until the limit of the voltage range determined by the battery check facility is reached (type test). In this process, the measuring equipment shall be loaded with a test resistance of U N × 1 000 Ω/V for a loading period not less than 5 s, with intervals of not less than 25 s prior to each new loading.
6.8 Stability test Tests shall verify that the indication of measured resistance of 1 (±1 %) MΩ is stable and does not change by more than 1 0 % when a capacitor of 2 (±1 0 %) µF (or a higher capacitance value, if specified) is connected in parallel. Resistance and inductance of the test capacitor shall be negligible (type test).IEC 61557-2 pdf download.