Practical Cable Sizing
A manufacturer’s cable datasheet contains a lot of information — here is which parts actually feed into a sizing calculation.
A manufacturer's cable datasheet often runs several pages, covering everything from mechanical construction to chemical resistance. For sizing purposes, only a handful of figures actually matter.
| Datasheet field | Why it matters for sizing |
|---|---|
| Conductor cross-sectional area | The basic size input for any ampacity lookup |
| Insulation maximum temperature rating | Determines which base ampacity table column applies |
| Voltage rating | Confirms the cable is genuinely rated for the circuit's actual operating voltage, particularly critical for DC solar applications |
| Conductor material (copper vs aluminum) | Genuinely different ampacity for the same cross-section |
| Resistance per unit length | Feeds directly into a manual voltage drop calculation, if you're checking outside a calculator tool |
Chemical resistance ratings, specific jacket color coding conventions, and detailed mechanical flexing specifications matter for application suitability and installation practicality, but don't feed directly into the ampacity/voltage-drop calculation itself.
Confirm your specific cable's rated figures match what you're entering into the OhmWorks Cable Sizing calculators.
Engr. Jason Morales — Founder, SolarEnergyPH & OhmWorks