Clearance and creepage distance is different for Compact NSX and Masterpact MTZ/NW in PrismaSeT I switchboard?
Definition of clearance: Clearance is the distance between two conductive parts along a string stretched the shortest way between these conductive parts.
The clearance distance depends upon the Rated impulse withstand Voltage Uimp. The Uimp of Masterpact MTZ/NW is 12 kV and Uimp for Compact NSX is 8 kV. Based on the IEC61439-1, Table 1, the minimum clearance distance for 12kV & 8kV Impulse voltage is 14mm & 8mm respectively. The bus bar clearance in PrismaSeT I column maintained are ≥ 14mm for Masterpact NW and ≥ 8mm where Compact NSX used. The line side clearance of NSX breaker will be ≥ 14mm.
Definition of Creepage: Creepage distance is the shortest distance along the surface of a solid insulating material between two conductive parts.
The creepage distance depends upon the Rated Insulating Voltage Ui and the insulation material group. The insulating voltage of Masterpact MTZ/NW is 1000V and Compact NSX is 750V. The material group is IIIa. Based on the IEC61439-1, Table 2, the minimum creepage distance for 1000V insulating voltage is 16mm and up to 800V is 12.5mm. The creepage distance for PrismaSeT I column maintained are ≥ 16mm for Masterpact MTZ/NW and ≥ 12.5mm where Compact NSX used.