Cable tests that are not equivalent, and why
IEC 60228 (20 °C) ≠ IS 10810 (27 °C)
Not equivalent, because India conditions and measures at 27 °C and corrects resistance with its own coefficient: convert a reading before applying an IEC limit.
IEC 60228 (20 °C)
- Resistance at 20 °C; the correction uses 0.00393 per kelvin for copper and 0.00403 for aluminium. Sources: IEC 60228:2023, Annex B, p. 18 (resistance corrected to 20 °C) (read in the standard)
IS 10810 (27 °C)
- Reference room temperature 27 ± 2 °C for conditioning and for the tests at room temperature. Sources: IS 10810 Parts 7, 30, 43, 58, 60, 63 and 64 (conditioning and tests at room temperature) (read in the standard)
- Resistance corrected to 20 °C with one coefficient, 0.004 per kelvin, for copper and aluminium alike; the difference from IEC 60228 stays under about 0.2 % from 5 to 50 °C. Sources: IS 10810 (Part 5):1984, Table 1 and its note, pp. 2-3 (read in the standard)
Values as the sources print them, every one with its source and how it was seen; where a value is not held, it says so. The cable's own standard and the specification decide which test applies.
Questions and answers
Is IS 10810 (27 °C) equivalent to IEC 60228 (20 °C)?
No. India conditions and measures at 27 °C and corrects resistance with its own coefficient: convert a reading before applying an IEC limit.