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C6.3
BUSBAR INSULATION
The busbars shall be insulated from the busbar casing to maintain a clearance
and creepage distance as specified in IEC 60439-2:2005 with Pollution Degree 3.
The insulation material shall be of heat resistant, self-extinguishing, nonhygroscopic, high electrical and mechanical strength to withstand the stresses
under all normal and short-circuit conditions.
C6.4
BUSBAR
Busbars shall be three phase and full rated neutral made of hard drawn, high
conductivity solid copper bars to BS EN 13601:2002.
The busbar including all electrical contact surfaces shall be silver or tin plated.
The busbars shall be of adequate size to carry the rated current continuously at
mean ambient temperature of 35 oC and shall not exceed the temperature rise
limits in accordance with Clause 7.3 of IEC 60439-2:2005.
Each bar shall be painted to indicate the phase to which it is connected. Painting
shall comprise a band of color at each accessible position to the busbars.
C6.5
FEEDER UNIT
Feeder unit shall be of manufacturer‟s proprietary product. The rated current
and rated short-time withstand current of the feeder unit shall not be less than
that of the busbar trunking system to which it is connected.
C6.6
TAP-OFF UNITS
Tap-off units shall be used for branch circuits taken off from the busbars.
MCCB to IEC 60947-2:2009 or H.R.C. fuses to IEC 60269-1:2009 and other
associated Parts of the Standard of appropriate current ratings and short-circuit
breaking capacities shall be provided as near as practically possible to the
tapping position for protection of the branch circuits.
Plug-in tap-off units shall be attached on the busbar casing and held in position
by means of wing nuts or other quick fastening and quick releasing device.
Tap-off units shall make positive earth connection and shall be equipped with
internal barriers to prevent direct contact.
Mechanical interlock shall be incorporated such that the tap-off unit cannot be
inserted or removed from the busbar trunking unless it is in the switch OFF
position.
Section C6
Page 2 of 7
EE_GS
2012 Edition