Engineering tool

Cable Tray Fill & Sizing Selector

Enter a cable schedule and get the required tray cross-section and the smallest catalogue tray that satisfies your design fill ratio: a fast, standards-referenced way to shortlist a section.

For preliminary selection only. This tool sizes a tray by cross-sectional fill against published practice. It does not compute load capacity, support span, deflection or ampacity/derating, and states no safe-working-load figure; those are the manufacturer's classified data (IEC 61537) and the responsible engineer's calculation. Verify every result against project conditions, the applicable code and a qualified engineer before specifying.

1 · Cable schedule

Enter each cable type by quantity and overall (outer) diameter. Take the OD from the cable maker's datasheet, not the conductor size.

QtyOuter Ø (mm)

2 · Design fill ratio

The maximum cross-sectional fill you are designing to. Set this to the value the applicable code and your derating (IEC 60364-5-52) require: these are common practice, not a rule this tool imposes.

30%: conservative / heat-sensitiveLower fill where grouping/derating (IEC 60364-5-52) or heat dissipation governs.40%: power cables (typical)Common design practice for power cabling within NEC 392.22 limits.50%: control & signalHigher fill often accepted for control/instrumentation where ampacity is not the constraint.

3 · Preliminary result

Total cable area: 29.5 cm²
Required tray area @ 40%: 73.6 cm²
Single-layer min. width: 150 mm; Σ diameters (NEC 392.22(A), large power cables)
Cable types: 1

Catalogue match

Smallest listed tray that stays under 40% fill: SS316 Perforated Cable Tray 300×100, CT-SS316-300 at 9.8% fill.

Tray (W×H)	Material	Fill	1-layer
300×100 mmCT-SS316-300	SS316	9.8%
300×100 mmCT-HDG-300	HDG	9.8%

Standard basis

Fill practice cited by this tool. Full conformance evidence for any specific tray is provided with its quotation.

NEC / NFPA 70 · Art. 392.22: Allowable cable-tray fill for multiconductor cables rated 2000 V or less, and the single-layer diameter-sum rule for large power cables.
NEMA VE 2: Cable Tray Installation Guidelines: recommended cross-sectional fill practice.
IEC / BS EN 61537: Cable-tray system product standard (mechanical load classification). Used here only to point you at the tray's declared class; no figure in this tool is derived from it.

The gross W×H envelope is used for the fill figure; usable loading depth, side-rail thickness and any barrier strips must be taken from the manufacturer's drawing. Outer diameters are the cable maker's stated OD.