Free Cable Tray Fill Calculator
Determine the fill ratio for a cable tray based on cable cross-sections and tray dimensions.
in
in
in
Tray Fill
18.4 %
Tray Cross-Section48.0 sq in
Max Cables at 40% Fill43
Tray Fill vs Tray Width
Cable Tray Fill
Fill % = (Number of Cables x Cable Area) / Tray Area x 100
NEC Article 392 limits fill for cable trays. For multiconductor cables in a solid-bottom tray, total cable area must not exceed the tray cross-section area (the depth restriction acts as the limit). A practical target of 40% fill allows room for future additions and airflow.
Example Calculation
20 cables (0.75 in OD) in a 12 x 4 inch tray.
- 01Tray area = 12 x 4 = 48 sq in
- 02Cable area each = pi x 0.375 squared = 0.442 sq in
- 03Total cable area = 20 x 0.442 = 8.84 sq in
- 04Fill = 8.84 / 48 x 100 = 18.4%
- 05Well within limits.
Frequently Asked Questions
Learn More
How to Calculate Concrete Needed for Any Project
Learn how to calculate the exact amount of concrete needed for slabs, footings, columns, and other projects. Covers volume formulas, waste factors, and ordering tips.