Underground electrical works

Electrical Trench Sand Quantity Calculator

Estimate the sand volume below and above underground electrical cables or ducts from explicit trench dimensions and sand layers.

Trench and sand inputs

The tool assumes the selected sand layers span the full entered trench width. Where ducts, cable packs or non-sand zones occupy significant space, use a project-specific geometric deduction.
Enter trench length, width and sand depths.

Sand volume

Planning sand volume——
—Bedding volume
—Protective cover
—Base volume
—Allowance
—

Sand-volume methodology

Each sand layer is treated as a rectangular prism. The calculator keeps bedding and protective cover separate because their depths may be specified independently.

Bedding volume = length × width × bedding depth
Cover volume = length × width × cover depth
Base volume = bedding + cover
Planning volume = base × (1 + allowance ÷ 100)

Example

A 120 m trench × 0.7 m wide with 0.10 m bedding and 0.15 m protective sand gives 8.4 m³ bedding plus 12.6 m³ cover, or 21.0 m³ base volume. With 8% allowance, the planning quantity is 22.68 m³.

Why the allowance is explicit

Delivered sand and installed trench volume are not always identical. Handling losses, uneven excavation and site conditions can change actual consumption, so the allowance should be project-specific.

Frequently Asked Questions

Can bedding depth be zero?

Yes when no sand bedding is planned.

Can cover depth be zero?

Yes, although that means no upper sand layer is included in the estimate.

Does this determine trench design?

No. Use the approved trench detail and cable installation requirements.

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