NEN 1010 §523
Cable derating factor
Correctiefactor kabelbelasting
Also known as: correctiefactor, reductiefactor, derating, belastbaarheid, stroombelastbaarheid, motor, temperature-correction, temperature-correction-factor, thermal-derating, ambient-temperature, temperatuurcorrectie, omgevingstemperatuur, kt-factor
Correction factor for cable loading: multiplier for Iz table value to account for ambient temperature (k1), bundling of multiple circuits in one duct (k2), and soil parameters (Rth). Bundling of 6 circuits typically yields k2 ≈ 0.57.
Practical example
Cable load correction factor. Six circuits sharing one cable tray receive a correction factor k2 ≈ 0.57, significantly reducing the allowable current per cable below the tabulated value.
Common mistake
Cable load correction factor. Common mistake: copying Iz table values directly without accounting for grouping or high ambient temperature — the cable may overload in practice.
See also
Related terms
In-depth guides
- → §523 Cable cross-section & current-carrying capacity
- → §537 Power factor correction (cosφ) for heavy motor loads
- → §433 Overload protection (§433) — the coordination rule Ib ≤ In ≤ Iz and I₂ ≤ 1.45 Iz
- → NEN-EN-IEC 61439-1/-2 (3e editie) Group rated current replaces the simultaneity factor — sizing the main cable and distribution board
- → IEC 60755 RCD types AC/A/F/B — classification and selection by load type (IEC 60755)
- → §528 (IEC 60364-5-52) §528 — Proximity to non-electrical services: why a cable should not just run next to a gas pipe
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