Electrical Calculators

Box Fill

Organize conductor, clamp, device, and grounding allowances.

01

Inputs

02

Result & worksheet

22.50 in³ required — fits

Recorded summary

  • Required: 22.50 in³
  • Available: 22.5 in³
  • Margin: 0.00 in³

Formula used

Required volume = conductor allowances + yoke allowances + internal clamp/support allowance + grounding allowance

Calculation steps

  1. 6 × 2.25 = 13.50 in³ conductors
  2. 1 × 4.5 = 4.50 in³ yokes
  3. + 2.25 clamps/support + 2.25 grounding = 22.50 in³

Assumptions

  • Counts and allowances were determined using the adopted edition
  • Pass-through, looped, spliced, and equipment grounding conductors were counted correctly
  • Box volume is marked by the manufacturer or otherwise verified

Verify before use

  • NEC 314.16 and the applicable volume-allowance table
  • Rules for clamps, support fittings, devices, grounding conductors, barriers, and fittings
  • Manufacturer box markings and listed extensions
  • Special treatment for large conductors or cable assemblies