Temperature adjusted resistance calculator

Use this calculator when a cable data source gives resistance at one temperature and the project record needs a resistance value at another temperature before voltage-drop, cable-loss or candidate cable review. The page is for source-record arithmetic, not for selecting cable size or proving compliance.

The useful output is the adjusted resistance in ohm/km, the percent change from the entered base value and a route-resistance handoff. It should travel with the source value, coefficient source and temperature basis so another reviewer can repeat the calculation.

Field Use Cases

This page is especially useful when a downstream calculator asks for resistance in ohm/km and the available source value has a temperature basis that does not match the review basis. It does not decide whether the operating temperature is realistic.

Data Checklist

The coefficient is a source value. Do not treat a preset as a universal rule. Copper, aluminium, alloy, conductor condition and source method can change what coefficient is appropriate.

Method Comparison Matrix

The method is deliberately narrow so the adjusted resistance can be reused by other calculators without hiding where it came from.

Worked Records

These records show why temperature basis matters. A resistance value can look precise but be wrong for the downstream calculation if the temperature basis is not carried with it.

Review Workflow

1. Identify the cable record and resistance source.
2. Confirm the base resistance and base temperature belong together.
3. Enter the operating-temperature basis being reviewed.
4. Enter the coefficient from the project, manufacturer or reviewed source.
5. Enter the route length only if a route-resistance handoff is useful.
6. Read adjusted resistance and percent change together.
7. If the change is large, recheck conductor material, source basis and operating assumption.
8. Carry the adjusted value into voltage drop, cable loss or candidate cable work only with its source record attached.
9. Do not use the result as current capacity, derating, cable selection or compliance approval.

Boundary With Voltage Drop, Cable Loss And Cable Size

Keeping the boundary clear prevents a helpful resistance adjustment from becoming a hidden cable-selection method.

Australian Context

Australian cable work often uses values from standards context, project documentation, manufacturer data, cable schedules and competent review. This calculator does not reproduce those tables or decide which values apply. It records the arithmetic consequence of values entered by the user.

Where a current standard, authority condition, DNSP requirement, product instruction or project specification sets a stronger requirement, that source controls the project decision. The calculator output is a documented worksheet value.

Minimum Export Record

Stop Points

• The resistance source does not state material, conductor or temperature basis.
• The coefficient is copied from another material or unknown source.
• The operating temperature is selected only to make a downstream result look better.
• The adjusted value is being used without the source record.
• Route length is still a rough drawing distance and route resistance matters.
• The result is being treated as cable selection, current capacity, derating or installation approval.

A useful record states the resistance source, base temperature, operating basis, coefficient and adjusted resistance. That makes later voltage-drop and loss calculations easier to review.