Why the Phase to Phase distance of Masterpact NW40H1-3P & NW40H1-4P Horiontal connection ACB is uneven, please confirm the technical reason for the same.
This phase to phase distance is as per Masterpact NW design constraints.
Masterpact NW is complies for isolation in compliance with IEC60947-2.
The minimum space in the rear connection terminals ( between two poles) is 15mm. And as per the IEC International insulation rules it should be minimum 14mm at 1000V.
Please refer the table 13 of the IEC 60947-1 defines the withstand voltage in KV regarding of the distance.
For example, impulse voltage of NW is Uimp = 12kV. It means, the clearance or distance between the live part and the ground must be 14mm (as a minimum). Please refer the attached IEC extract sheet showing the same.
So even in the different phase to phase gap in the NW40 4P ACB, it is complying with the IEC 60947-2 requirement.