IEC 60439-2:2005 pdf free download

IEC 60439-2:2005 pdf free download
IEC 60439-2:2005 pdf free download.Low-voltage switchgear and controlgear assemblies
7.1.1 .6 Busbar trunking fire barrier unit
A busbar trunking fire barrier unit shall be designed to prevent the propagation of fire, for a specified time, under fire conditions, when the busbar trunking system passes through horizontal or vertical building divisions (for example, wall or floor).
Compliance is checked by the fire-resistance test according to 8.2.1 5.
7.1.1 .7 Maintenance of circuit integrity under fire conditions
A fire-resistant busbar trunking unit may be designed to maintain the integrity of electrical distribution circuits, for a specified time, under fire conditions.
A test for circuit integrity under fire conditions is under consideration (see annex L).
7.1.2.3.4 Clearances
After the first paragraph, add the following paragraph:
Clearances shall be dimensioned, when the busbar trunking system is correctly assembled in accordance with the manufacturer’s instructions and mounted as in service, to withstand the required impulse voltage stated by the manufacturer, considering the overvoltage category and the maximum of the rated operational voltage to earth, as specified in IEC 60439-1 ,table G.1 .
Unless otherwise stated by the manufacturer, the dimensioning of the clearances of the system shall be based on:
– overvoltage category: IV (origin of installation) or III (distribution circuit level);
– pollution degree: 3.
NOTE Clearances values for basic and functional insulation are dimensioned as specified in IEC  0439-1,table 1 4, case A. Clearance values of supplementary insulation are not less than those specified for basic insulation. Clearance values for reinforced insulation are dimensioned to the rated impulse voltage one step higher than those specified for basic insulation.
Parts of the system provided with double insulation where basic insulation and supplementary insulation cannot be tested separately are considered as reinforced insulation.
7.1.2.3.5 Creepage distances
a) Dimensioning
After the first paragraph, add the following paragraph and note:
Creepage distances shall be dimensioned, when the busbar trunking system is correctly assembled in accordance with the manufacturer’s instructions and mounted as in service, for the rated insulation voltage of the system stated by the manufacturer.