IEC 62040-1-2021 Uninterruptible power systems (UPS) – Part 1: Safety requirements

IEC 62040-1-2021 Uninterruptible power systems (UPS) – Part 1: Safety requirements. 4 Protection against hazards Clause 4 of IEC 62477-1 :201 2 applies, except as follows: 4.2 Fault and abnormal conditions Subclause 4.2 in IEC 62477-1 :201 2 applies, except as follows: Replace the fourth paragraph of IEC 62477-1:2012, 4.2 by the following: Compliance is checked by analysis or by test according to 5.2.4.6 of IEC 62477-1:2012. Compliance through analysis only is permitted when such analysis conclusively shows that no hazard will result from failure of the component. 4.3 Short-circuit and overload protection Subclause 4.3 in IEC 62477-1 :201 2 applies except as follows: Add the following: 4.3.1 01 AC input current The input current to the UPS shall not exceed that declared by the UPS manufacturer – see 6.2 a). In determining the steady state input current, the consumption due to optional features offered or provided by the manufacturer for inclusion in or with the UPS shall be considered and adjusted to give the most unfavourable result. NOTE Transient input current arising from dynamic occurences, for example inrush or overload current, is not considered. Compliance is checked when highest current measured or calculated (as applicable) when performing the test described in 5.2.3.102 does not exceed the input current declared by the manufacturer (see 6.2). 4.3.1 02 Transformer protection Transformers shall be protected against overtemperature. NOTE Means of protection include: • overcurrent protection, • internal thermal cut-outs, • use of current limiting devices. Compliance is checked by the applicable tests of 5.2.3.104. 4.3.1 03 AC input short-circuit current The UPS manufacturer shall specify the rated conditional short-circuit current (I cc ) or the rated short-time withstand current (I cw ) at each AC input port of the UPS. The UPS manufacturer may specify both. Individual AC input ports of a UPS may have individual ratings. A UPS with AC input ports that may be configured with jumpers or busbars to present a single AC input port or multiple AC input ports shall be tested as having multiple AC input ports. Testing with installed jumpers or busbars that combine multiple AC input ports into a single AC input port is not required when the construction of the jumpers or busbars is at least as robust as that of the phase conductors in terms of cross-sectional area, mechanical support and clearance. A UPS with multiple AC input ports and different ratings for...