Definition of a power busbar
Power busbar
Clearances and creepage distances (contd.) Standards
Good practice
IEC 61439-1
The distance between two phases varies according to the switchboard architecture (equipment installed inside the switchboard, available space, etc.).
Example Prisma
The bars are mounted on insulated supports and the distance between each phase is 75 mm.
The switchboard designer must optimize this distance in order to: - facilitate connections, - ensure that the minimum clearance and creepage distances recommended by the standard are verified at all points of the switchboard. Schneider Electric proposes two levels of busbars to facilitate connections.
2
For a service voltage of up to 1000 V, the clearance distance between a powered bare part (copper bar) and a covering panel that is likely to be deformed after an impact (for example, IK protection degree test), must be at least 20 mm.
Example Prisma
Schneider Electric has conducted tests on enclosures according to their IK impulse protection degree. These tests have ensured that the clearance distance was maintained.
If this is not possible, place an insulating barrier between them.
20
IEC 61439-1
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IEC 61439-1
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ยง 8.3.2 Appendix F
5
40
Make sure that clearance and creepage distances are compliant with the standard, They must be measured using the methods given in Appendix F of the standard.
Example Prisma
For a busbar with a rated clearance voltage Ui of 1000 V and a rated impulse withstand voltage Uimp is 12 kV, and there must be a clearance of at least 14 mm.
The deformation of the enclosure or internal partitions that may result from a short-circuit must not permanently reduce clearance or creepage distances to values lower than those specified by the standard.
When installing a power busbar, always take the partitions and cover panels into account when observing clearance distances.
version: 5.0
How to assemble an electrical switchboard