Tray Fill

Occupancy of a cable tray, by area and by width.

1. What this check does

Reports how much of the tray cross-section the cables occupy, and how much of the tray width they would take in a single layer. Calculated in your browser.

2. Inputs used

Tray inside width and usable depth.
Outside diameter and quantity of each cable.

3. Formulas and assumptions

Area used

\dfrac{\sum_i \frac{\pi}{4} d_i^2\, n_i}{W\,H} \times 100\ \%

Width used

\dfrac{\sum_i d_i\, n_i}{W} \times 100\ \%

W tray inside width, H usable depth.

Symbols

$d_i,\ n_i$	Cable outside diameter and count of type i	in or mm
$W$	Tray inside width	in or mm
$H$	Usable tray depth	in or mm

Cable tray cross-section with a single layer of cables; the sum of diameters is compared with the tray inside width. — **Figure 1.** Single-layer cable tray: sum of cable diameters against usable width.

Round cables; no allowance for spacing or maintained spacing.

4. What is NOT checked

Allowable fill, which depends on cable type, size, voltage and tray type.
Tray load rating and support spacing.
Ampacity in tray.

5. Reference standards

Pointers only; consult the edition adopted by your authority having jurisdiction.

NEC 2023 392.22 — number of conductors or cables
NEMA VE 1 / VE 2 — tray manufacture and installation

6. Validation cases

No worked example with a published answer is registered for this page yet. Have one we should add? Use the Feedback link. All cases: Validation.

7. Known issues and changes

See the Engineering Notes. Try the tool: Tray Fill.