Cable bend radius calculator

Preliminary estimate

Inputs

Calculation note

Use the cable manufacturer multiplier when available. The default is only a planning example.

Method

Minimum radius = cable OD x bend multiplier

Minimum bend diameter = minimum radius x 2

Radius with allowance = minimum radius x (1 + allowance percent / 100)

MoreLess

Formula variables

  • Cable OD is the actual outside diameter in millimetres.
  • Bend multiplier is the selected manufacturer or product-family value.
  • Allowance percent is an optional extra layout margin.
  • Radius is measured to the bend centreline unless manufacturer data states otherwise.

Assumptions

  • Bend radius is calculated from cable outside diameter and the selected multiplier.
  • The multiplier is a user-selected planning value; cable manufacturer instructions govern the actual bend limit.
  • The optional allowance is added after the minimum radius calculation for layout conversation only.
  • Cable construction, voltage class, armour, shielding, pulling setup, and field conditions can change the usable radius.

Examples

Armoured cable layout. A 28 mm OD cable with a 6x multiplier gives a 168 mm minimum radius and 336 mm bend diameter.

Manufacturer-data workflow. Replace the multiplier with the cable data sheet value when the actual construction or voltage class is known.