DinSketchUnderstand the table assumptions
The tool uses the B2 copper/PVC model identified in its interface. Review the table conditions and the temperature and grouping factors. Other installation methods and materials need appropriate data rather than an assumption that the same result applies.
Follow the sizing sequence
Determine design current first. Apply the relevant factors and compare the chosen conductor ampacity with the load. If the result is near a boundary, review actual operating conditions and equipment documentation carefully.
Complete the other checks
Also evaluate voltage drop, overload protection, fault current and disconnection conditions. A minimum-area calculation does not prove cable suitability in every operating mode or replace an engineering design.
Questions and answers
Can I choose a wire size directly from watts?
Convert power to current using the supply model and power factor, then assess installation conditions.
Why use correction factors?
Temperature and grouped installation can change ampacity relative to the table reference conditions.