--- Skip to content
Design 2025-06-22 · 9 min

Cable tray types and fill calculation

How to select a cable tray per IEC and calculate fill. Tray types, fill factor, calculation example.

Author: GorkyCAD Team

Cable tray types

Per IEC 61537: ladder (power cables, maximum load capacity), perforated (universal), wire mesh (light, for low-current networks), solid (for fire-hazard zones).

Fill factor

Total cable cross-section must not exceed 40% of tray cross-section for power circuits and 50% for control. Formula: Scable = Σ(π × d² / 4) × 1.1 (safety factor for uneven laying).

Calculation example

Given: 12 cables 5×2.5 mm² (d=10.2 mm), 5 cables 5×6 mm² (d=13.5 mm). Total area: S = 12 × 81.7 + 5 × 143.1 = 1696 mm². With 1.1 factor: 1865 mm². At 40% fill: Stray ≥ 1865 / 0.4 = 4663 mm² → select 200×50 tray (usable area ≈ 6000 mm²).

Frequently asked questions

Is this article free?
Yes, all articles and calculators are completely free.
Where can I run calculations?
The site offers 21 free calculators: cable sizing, breakers, RCD, voltage drop and more.
How do I prepare an electrical project?
In GorkyCAD Pro: plans, panels, calculations and a PDF set for free.
Found an error in the article?
Write to hello@gorkycad.pro — specialists will review and correct it.

Open free calculators →

Related tools

Open free calculators →