IEC 60670-24-2005 pdf – Boxes and enclosures for electrical accessories for household and similar fixed electrical installations – Part 24: Particular requirements for enclosures for housing protective devices and similar power consuming devices.
1 Scope This clause of Part 1 is replaced by: This part of IEC 60670 applies to empty enclosures and parts of them for electrical accessories intended to be used with a rated voltage not exceeding 400 V and a total incoming load current not exceeding 125 A for household and similar fixed electrical installations, where a maximum capability to dissipate power in normal use is declared by the manufacturer. These enclosures are intended for housing protective devices and devices with or without power dissipation. They are intended to be installed where the prospective short circuit current does not exceed 10 kA unless they are protected by current limiting protective devices with a cut-off current not exceeding 17 kA. Enclosures complying with this standard are suitable for use, after installation, at ambient temperature normally not exceeding 25 °C, but occasionally reaching 35 °C over 24 h, max. 40 °C and min. –5 °C. An enclosure which is an integral part of an electrical accessory and provides protection against external influences (e.g. mechanical impacts, ingress of solid objects or of water), is covered by the relevant standard for such an accessory. NOTE In UK enclosures complying with this standard cannot be used for the assembly of customer distribution boards (consumer units). Such products must comply with IEC 60439-3 [British standard EN 60439-3]. 2 Normative references This clause of Part 1 is applicable with the following addition: IEC 60417-DB:2002 2) , Graphical symbols for use on equipment 3 Definitions This clause of Part 1 is applicable with the following modification: 3.101 maximum capability to dissipate power (P de ) maximum capability of the enclosure to dissipate in normal use the power losses of the installed devices, as declared by the manufacturer NOTE P de is expressed in watts (W).
3.102 rated current current assigned by the manufacturer of the incoming device(s). If there is more than one incoming device, the current assigned by the manufacturer is the arithmetic sum of the currents of all incoming devices intended to operate simultaneously 3.103 rated voltage voltage assigned to the enclosure by the manufacturer 4 General requirements This clause of Part 1 is applicable. 5 General notes on tests This clause of Part 1 is applicable. 6 Ratings Void. 7 Classification This clause of Part 1 is applicable with the following modifications: Table 1 – Classification of boxes and enclosures Classification criteria 7.7.2 and 188.8.131.52 do not apply.
c) rated voltage; d) rated current/highest permanent incoming current as declared by the manufacturer; e) the symbol for class II, if applicable (IEC 60417-5172 (DB 3) :2003-02)) f) reference number of this standard i.e. IEC 60670-24; g) type designation, reference number or catalogue number; h) maximum temperature during the building process if 90 °C; i) for boxes and enclosures classified according to 7.3.7 (without inlets), the necessary information concerning the openings that can be made during installation; j) maximum capability to dissipate power (P de ); NOTE 2 In case of an enclosure designed with ventilation openings, the maximum capability to dissipate power (P de ) should be declared by the manufacturer, with the ventilation openings both covered and uncovered. k) for boxes and enclosures classified according to 7.7 the usability for hollow wall installation; l) the corresponding dimension sheet. The items c), d), f), h), i), j) and k) shall be marked on the boxes or enclosures or provided by the manufacturer on the smallest package unit or in the instructions of the manufacturer. Add the following subclause: 8.101 Required data for instruction sheet and/or documentation The manufacturer shall include in the documentation accompanying the enclosure the necessary instructions for installation. The manufacturer shall also provide appropriate information regarding the means (for instance glands, grommets, barriers…) to be used to obtain the intended degree of protection. The manufacturer shall declare the maximum capability to dissipate power (P de ) of the enclosure, according to the appropriate mounting environment, measured according to Clause 101 and provide appropriate documentation. NOTE An example of the use of the maximum capability to dissipate power (P de ) is given in Annex A.