Free Trunk & Conduit Sizing Spreadsheet: Accurate cable enclosure sizing is critical to protect conductors, maintain flexibility, and comply with electrical standards. Our Free Trunk & Conduit Sizing Spreadsheet uses the 40% filling‑ratio formula to help you instantly calculate the required trunk or conduit diameter based on cable counts and diameters. Designed for electrical engineers, MEP coordinators, and installers, this Excel tool eliminates guesswork and manual calculations so you can select the right enclosure sizes in seconds.
Key Features
Trunk Sizing Calculator
Filling‑Ratio Formula N×Ac=F×AtN \times A_c = F \times A_t where FF=40% occupancy factor
Inputs
Number of cables (N)
Cable OD (Dc)
Trunk width (W) & height (H)
Outputs
Minimum trunk cross‑section (At)
Recommended trunk dimensions
Conduit Sizing Calculator
Occupancy‑Based Sizing N×Aw=F×AcN \times A_w = F \times A_c for 40% occupancy
Inputs
Cable OD (Dw)
Conduit OD (Dc)
Outputs
Required conduit internal diameter
Max cable count per conduit
Cable & Enclosure Tables
Predefined data for common cable sizes (power, data, telecom)
Standard conduit and trunk dimension lookup
Automatic filling‑ratio checks and warnings
Free Trunk & Conduit Sizing: How to Use
Download & Open
Get the free .xlsx file via the download link.
Enter Cable Data
Input the number of cables and their overall outside diameters.
Select Enclosure Type
Choose “Trunking” or “Conduit” mode from the dropdown.
Review Calculated Sizes
The tool displays minimum width/height for trunking or internal diameter for conduits.
Export Results
Copy the summary table into your design report or BOQ.
Benefits for Electrical Designers
Time Savings
Automates filling‑ratio calculations, cutting manual effort by up to 80%.
Error Reduction
Built‑in validation flags over‑filled enclosures before installation.
Standards Compliance
Ensures a 40% maximum occupancy in line with IEC/BS EN wiring regulations.
Procurement & Installation
Generates precise sizing tables for purchasing and site installation teams.
Free Trunk & Conduit Sizing: Pro Tips
Always verify local code requirements—some jurisdictions limit occupancy to 35% for mixed‑cable types.
Use the cable‑type dropdown to quickly select from common power, control, or telecom cables.
Cross‑check cable bend radius and spacing for easier pulling and maintenance.
Combine with our Cable Tray Sizing Calculator for end‑to‑end cable management.
Download & Compatibility
File Format: .xlsx (Microsoft Excel)
Compatibility: Excel 2010+, LibreOffice Calc, Google Sheets
License: Free for commercial, educational, and personal use
Support: Unprotected input cells; formulas protected to prevent accidental change.
