IEC 61439-2:2009 pdf download – Low-voltage switchgear and controlgear assemblies – Part 2: Power switchgear and controlgear assemblies
7 Service conditions
This clause of Part 1 is applicable.
8 Constructional requirements
This clause of Part 1 is applicable except as follows.
8.2 Degree of protection provided by a ASSEMBLY enclosure
Replacement of the title:
8.2 Degree of protection provided by a PSC-ASSEMBLY enclosure
Subclause 8.2.1 of Part 1 is not applicable.
Additional subclause:
8.2.1 01 Degree of protection of withdrawable parts
The degree of protection indicated for PSC-ASSEMBLIES normally applies to the connected position (see 3.2.3) of withdrawable parts. The ASSEMBLY manufacturer shall indicate the degree of protection obtained in the other positions and during the transfer between positions. PSC-ASSEMBLIES with withdrawable parts may be so designed that the degree of protection applying to the connected position is also maintained in the test and isolated positions and during transfer from one position to another.
If, after the removal of a withdrawable part, the original degree of protection is not maintained, an agreement shall be reached between the ASSEMBLY manufacturer and user as to what measures shall be taken to ensure adequate protection. Information provided by the ASSEMBLY manufacturer may take the place of such an agreement.
8.3.2 Clearances Addition: Where functional units are mounted on withdrawable parts, the isolation provided in the isolated position shall at least comply with the requirements in the relevant specification for disconnectors (see IEC 60947-3).
This applies with the equipment in new condition, taking account of the manufacturing tolerances and anticipated changes in dimensions due to wear. The isolating distance between the withdrawable unit main contacts and their associated fixed contacts in the isolated position shall be capable of withstanding the test voltage for the declared impulse withstand voltage as specified in Table 1 02.
8.4.3.2.2 Requirements for earth continuity providing protection against the consequences of faults within the ASSEMBLY Replacement of last paragraph: When removable or withdrawable parts are equipped with a metal supporting surface, these surfaces shall be considered sufficient for ensuring earth continuity of protective circuits provided that the pressure exerted on them is sufficiently high. The continuity of the protective circuit of a withdrawable part shall remain effective from the connected position to the isolated position inclusively.
8.4.5.1 Devices to be operated or components to be replaced by ordinary persons This subclause of Part 1 is not applicable.
8.4.5.2 Requirements related to accessibility in service by authorized persons Additional subclause:
8.4.5.2.1 01 Operating and maintenance gangways within a PSC-ASSEMBLY Operating and maintenance gangways (see 3.1 02.1 and 3.1 02.2) within an ASSEMBLY shall comply with the requirements for basic protection as specified in IEC 61 1 40. The design and construction of such gangways shall be agreed upon between ASSEMBLY Manufacturer and User . Recesses within a PSC-ASSEMBLY of limited depth, in the order of 1 m, are not considered to be gangways.
8.5.2 Removable parts
Replacement of the title:
8.5.2 Removable and withdrawable parts
Additional subclauses:.
8.5.2.1 01 General
The removable and withdrawable parts shall be so constructed that their electrical equipment can be safely isolated from or connected to the main circuit whilst this circuit is live. The removable and withdrawable parts may be provided with an insertion interlock (see 3.2.5 of Part 1 ). Minimum clearances and creepage distances (see 8.3 of Part 1 and 8.3.2 above) shall be complied with in the different positions as well as during transfer from one position to another. NOTE It may be necessary to ensure that these operations are not performed under load.
8.5.2.1 02 Removable parts Removable parts shall have a connected position (see 3.2.3 of Part 1 ) and a removed position (see 3.2.4 of Part 1 ).
8.5.2.1 03 Withdrawable parts Withdrawable parts shall have in addition an isolated position (see 3.2.1 03) and may have a test position (see 3.2.1 02), or a test situation (see 3.1 .1 02). They shall be distinctly located in these positions. These positions shall be clearly discernible.
