IEC 61557-2 pdf free download
IEC 61557-2 pdf free 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.
6.5 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 10 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 61010-1:2010, 16.2.
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 pF 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 UN x 1 000 0/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 %) MO is stable and does not change by more than 10 % when a capacitor of 2 (±10 %) pF (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.
