The electrical busbars inside the switchboards shall be of plain hard-drawn, high conductivity, electrolytic copper bars in accordance with BS EN 13601: 2002, and of adequate rectangular cross-section to carry continuously the specified current without overheating and shall be rigidly mounted on non-hygroscopic insulators so as to withstand any mechanical forces to which they may be subjected under maximum fault condition.
Busbars shall be colored red, yellow, blue and black at appropriate points to distinguish the phases and neutral. No tapes shall be used. The main busbars shall be arranged in a horizontal plane and in the order of red, yellow, blue and neutral phases from back to front. On each panel connections shall be red, yellow, blue and neutral phases from left to right viewed from the front of the panel.
The phase and neutral busbars should be located in the top compartments of the switchboard.
The busbar system shall be readily accessible for inspection, construction and maintenance duties without the requirement of additional equipment. In case of a busbar short circuit, it shall be possible to clean or to replace the busbars and the support system without stripping the assembly.
In the busbar compartment the phase busbars may not be fully insulated. However, each phase busbar shall be able to withstand at least an applied AC test voltage of 2.5 kV for a period of 60 seconds.
The droppers shall have full segregation by insulated materials. The insulation of the busbar jointing and branching points shall be of equal quality to that of the main bars and shall be removable and easily replaceable for inspection.
The neutral bar may be not insulated in the busbar compartment but shall be insulated at all other compartments with the same insulation level as the phase busbars.
The earth bar shall be located in the top or bottom compartment and in all cable riser compartment of the switchboard and shall be easily accessible. Sufficient connection points with adequate terminating facilities shall be provided for terminating the cable earth leads. The earth bar shall be sized complying with IEC 60439-1.
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