These tests are applicable to prefabricated substations, intended to be qualified as class IACA/or IAC-B or IAC-AB with respect to protection of persons in the event of an internal arc at HV side. The tests shall be performed according to Annex A. These tests cover the cases of faults resulting in an arc occurring inside the prefabricated
substation in the HV switchgear and the HV interconnections with all doors closed (IAC-B) or with the door(s) used to give access to the HV switchgear open (IAC-A) (see Annex A). The validity of the results of a test carried out in a particular prefabricated substation design or representative part of it can be extended to another one (refer to 6.1), provided that the original test was more onerous and the latter design can be considered as similar to the one
tested in all the following respects:
– arc current and arcing time;
– directions of gas flow from the internal arc;
– dimensions and layout of the prefabricated substation;
– structure and strength of the enclosure, floor and partitions, if any;
– ventilation grids;
– performance of the pressure release device, if any.