Calculadora de Ocupação de Eletrocalha — Formula
## 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.
**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.
Exemplo Resolvido
20 cables (0.75 in OD) in a 12 x 4 inch tray.
- Tray area = 12 x 4 = 48 sq in
- Cable area each = pi x 0.375 squared = 0.442 sq in
- Total cable area = 20 x 0.442 = 8.84 sq in
- Fill = 8.84 / 48 x 100 = 18.4%
- Well within limits.