Estimate corrected cable current ratings, compare sizes, review drop limits. Generate practical tables for engineering decisions with clean exports.
| Material | Insulation | Installation | Load (kW) | Voltage (V) | Length (m) | Suggested Review |
|---|---|---|---|---|---|---|
| Copper | 90°C | Conduit | 18 | 415 | 30 | Check 10 mm² and above |
| Copper | 75°C | Tray | 37 | 415 | 55 | Check 25 mm² and above |
| Aluminum | 90°C | Buried | 52 | 415 | 80 | Check 70 mm² and above |
For three phase systems, load current is calculated as I = P × 1000 ÷ (√3 × V × pf × efficiency). For single phase systems, I = P × 1000 ÷ (V × pf × efficiency).
Adjusted ampacity is found by multiplying base ampacity by the ambient temperature correction factor and the grouping correction factor.
Single phase drop uses 2 × I × L × mV/A/m. Three phase drop uses √3 × I × L × mV/A/m. Percentage drop equals voltage drop divided by system voltage, then multiplied by 100.
A cable size is marked suitable when adjusted ampacity meets or exceeds the load current and the voltage drop remains within the selected limit.
Choose conductor material, insulation rating, and installation method first. Enter ambient temperature and grouped conductor count next. Add electrical load, voltage, phase type, power factor, efficiency, route length, and maximum voltage drop. Submit the form. Review the generated table and graph, then export the results if needed.
Cable ampacity defines the safe current a conductor can carry continuously. Correct sizing protects insulation, limits heating, improves service life, and reduces nuisance trips. Engineering reviews usually compare current demand, installation conditions, and acceptable voltage drop before final cable selection.
Published current tables usually assume standard reference conditions. Real projects rarely match those conditions exactly. Hot plant rooms, buried routes, grouped cables, and tray installations all change thermal performance. That is why engineers apply correction factors before approving a conductor size.
A cable can satisfy ampacity limits yet still fail a design check because of excessive voltage drop. Long routes often create this issue. When voltage at the load falls too far, motors run hotter, lighting output changes, and equipment reliability may decline. Good design reviews both current and drop.
This calculator produces a practical comparison table instead of a single answer. That makes it easier to review multiple conductor sizes together. You can see base ampacity, derated ampacity, estimated load current, voltage drop, and pass or check status in one place. The export options also help documentation.
This tool is intended for preliminary sizing and comparison. Final cable selection should follow the governing electrical code, insulation limits, short circuit duty, installation details, termination temperature ratings, harmonic content, and local authority requirements for the project.
Cable ampacity is the maximum continuous current a conductor can carry without exceeding its allowable temperature limit under defined installation conditions.
Higher ambient temperature reduces the cable’s ability to release heat. That lowers safe current capacity and requires a derating factor.
Grouped conductors warm each other. Mutual heating reduces heat dissipation, so grouped cables usually need a correction factor and sometimes a larger size.
Yes. It may pass current capacity but still fail voltage drop, short circuit, termination, or code requirements. Final review should check all design limits.
Copper usually carries more current per size and has lower resistance. Aluminum is lighter and often cheaper, but it may require a larger conductor size.
Select the method that best matches the real route, such as conduit, tray, or buried. Different methods change heat transfer and base current ratings.
It helps preliminary engineering checks and documentation. Final approval should always follow the required local code, manufacturer data, and project specifications.
They improve load current estimation. Motors and many practical loads draw current based on real operating conditions, not only rated power.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.