Wire, Cable & Conductor Manufacturing calculator

Concentric Extrusion Wall Thickness Calculator

Calculate nominal radial wall from concentric cable diameters. Enter finished and under-layer outside diameters plus the specified nominal wall.

What this calculator does

  • Calculate nominal radial wall from concentric cable diameters.

Formula used

  • Concentric radial wall = (Finished OD − Under-layer OD) ÷ 2
  • Nominal deviation = Concentric wall − Specified nominal wall
  • Diametral build = Finished OD − Under-layer OD

Inputs explained

  • Finished Outside Diameter: Measured or specified diameter after extrusion.
  • Diameter Under Extrusion: Outside diameter of the underlying construction.
  • Specified Nominal Radial Wall: Nominal radial wall from the cable construction.

How to use the result

  • Best suited to nominal extrusion build, Diameter-Based wall review.
  • Minimum local wall and dielectric acceptance require direct measurement and the applicable specification.

Current U.S. benchmarks

  • The producer price index for primary nonferrous metals (a broad metals benchmark, not copper alone) stands at 544.731 (BLS, Aug 2026), up 49.3% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,543 per tonne (IMF via FRED, Jul 2026).
  • The U.S. has 5,397 electrical equipment and appliances establishments employing about 369,437 workers (Census County Business Patterns, 2023).

Common questions

  • Is this measured minimum wall? No. Eccentricity can make local wall thinner than the concentric estimate.
  • Can equal diameters be entered? Yes. Equal diameters represent zero added radial wall.
  • Which underlying diameter is needed? Use the outside diameter immediately beneath the extrusion layer being evaluated.
  • Does a negative deviation reject the cable? It flags a difference from nominal; apply the actual specified tolerances and measurement method separately.

Last reviewed 2026-10-12.