How much earthing conductor do I need?

Add the measured route lengths, vertical drops and connection allowances, then apply a project-specific installation allowance.

Should equipment connection tails be included?

They should be included when they are part of the conductor takeoff. This calculator keeps their quantity and length visible.

Does this determine the required conductor size?

No. Conductor sizing is a separate electrical design requirement.

Earthing & bonding takeoff

Earthing Conductor Length Calculator

Estimate conductor length from horizontal routes, vertical drops and equipment connection tails, then add an explicit installation allowance.

Route inputs

Main route length

Parallel / repeated runs

Equipment connection points

Average connection tail per point

Additional joint / termination allowance per point

Installation allowance (%)

Length unit

Use the actual approved earthing route and conductor sizing design. This tool estimates quantity, not electrical adequacy.

Enter route and connection assumptions.

Earthing conductor takeoff

Planning length——

—Main routes

—Connection tails

—Joint allowance

—Base length

—

Length methodology

The main route is multiplied by the number of repeated runs. Each equipment point then contributes its average connection tail and its separate termination allowance.

Main route = route × runs
Connection tails = points × tail length
Joint allowance = points × joint allowance
Base = main route + tails + joint allowance
Planning = base × (1 + spare ÷ 100)

Example

An 86 m route repeated twice gives 172 m. Twenty-eight equipment points at 0.8 m each add 22.4 m, and a 0.25 m termination allowance adds 7 m. The 201.4 m base becomes about 215.5 m with 7% installation allowance.

Why the route and tails are separated

It helps explain where quantity growth is coming from. A small change in connection-point count can matter even when the main route length is unchanged.

Frequently Asked Questions

Can runs be one?

Yes.

Can connection points be zero?

Yes when the conductor run has no separate equipment tails.

Does this size the earthing conductor?

No. Use the approved electrical design for conductor size and configuration.