Estimate wire or cable bundle diameter, solve for a single-wire outside diameter, or estimate wire count with packing, braid, jacket, and mixed-size options.

Area-based planning estimate. Actual round-wire packing and cable lay can require a larger diameter; this is not a guaranteed fit or code-compliance check.

Include insulation in the finished outside diameter.

Packing and covering allowances

Default 1.2 is a planning assumption. 1 uses area alone, not actual circular packing.

Blank means zero. Added once to diameter.

Blank means zero. Twice the thickness is added.

Bundle Diameter Formula

The calculator estimates finished bundle diameter using the following area-based planning model. Verify the actual assembly; the model does not solve finite circle packing or guarantee physical fit.

BD = k × D × SQRT(N) + B + 2 × t
  • Where BD is estimated finished bundle diameter; use consistent length units
  • N is the number of wires
  • D is finished wire outside diameter including insulation; k is the selected planning factor (default 1.2), B is a diametral braid allowance, and t is radial jacket thickness. For mixed groups, replace D * SQRT(N) with SQRT(sum of quantity * diameter squared)

What is a Bundle Diameter?

Definition:

A bundle diameter is the total diameter of a collection of wires packed in a circular shape.

How to Calculate Bundle Diameter?

Example Problem:

The following example outlines the steps and information needed to calculate Bundle Diameter.

First, determine the diameter of wires. In this case, the wire diameters are 50 mm.

Next, determine the number of wires. For this bundle, there will be 100 wires.

Finally, calculate the bundle diameter using the formula above:

BD = k * D * SQRT(N) + B + 2 * t

BD = 1.2 * 50 * SQRT(100) + 0 + 2 * 0

BD = 600 mm using the default factor of 1.2 and zero covering allowances. With factor 1, the area-only equivalent is 500 mm; neither result guarantees actual packing fit.