§Annex_G Annex G (informative) — Recommended voltage drop limits and calculation examples EB SUMMARY

Annex G is **informative** — it doesn’t set mandatory thresholds, but gives widely accepted design practice benchmarks that typically satisfy the functional requirement of §525.1. **Recommended**: up to **3 %** for lighting circuits and up to **5 %** for other final circuits (sockets, motors, fixed equipment), measured from the point of supply. National codes or product standards may impose stricter limits. To account for reactive load, the full calculation is: `ΔU = K × I_B × L × (cosφ × R + sinφ × X)`, where `K` is the system factor (2 for single-phase L-N, √3 for three-phase balanced), `R` is the conductor AC resistance per unit length, `X` is the inductive reactance per unit length (from cable manufacturer). For purely resistive loads (`cosφ ≈ 1.0`), the `sinφ × X` term drops out. Annex G includes worked examples following the sequence: select installation method → base `I_z` → apply correction factors (§523.5 grouping, §523.6 temperature) → check `I_n ≤ I_z` → check `ΔU`. **Starting voltage dip** for motors and high-inrush loads must be checked separately — steady-state compliance with Annex G does not guarantee acceptable dip during start-up.

EB-authored summary for design convenience — NOT normative IEC text. Official standard IEC 60364-5-52:2009 available at webstore.iec.ch →.