Formula and Method
Required ampacity = load current x sizing factor / installation derating. The result is mapped to a reference conductor table.
Assumptions
- Reference copper ampacity table for preliminary sizing
- Aluminum is estimated with a reduced ampacity factor
- Local cable standard is not embedded in this first version
Important Warnings
- Final cable size must be checked against IEC, NEC, BS, or the applicable local standard.
- Voltage drop and short-circuit withstand must be verified separately.
FAQ
Why is this called a reference size?
Cable sizing depends on insulation, installation method, ambient temperature, grouping, and local code tables. This tool gives a starting point only.
Should I also run the voltage drop calculator?
Yes. A cable can pass ampacity but fail voltage-drop requirements on a long run.