Convert Circular Mils to Barns
Convert Circular Mils (cmil) to Barns (b) instantly and accurately.
Conversion Formula
b = cmil × 5.067074791e+18
About Circular Mils
A circular mil (cmil) is a unit used in electrical engineering to specify the cross-sectional area of round wires and cables. Equal to the area of a circle with a diameter of exactly one thou (one thousandth of an inch) - approximately 5.067 × 10⁻¹⁰ m² - it simplifies wire calculations: the cross-sectional area in cmil equals the wire diameter in mils, squared. US electrical codes (NEC/NEMA) specify conductor sizes in circular mils, and large cables are rated in thousands of circular mils (kcmil or MCM). A 12 AWG wire, common in US household wiring, has a cross-section of 6,530 cmil.
About Barns
A barn (b) is a unit of area used in nuclear and particle physics to measure effective cross-sections of atomic nuclei and particle interaction probabilities. Equal to 10⁻²⁸ m² (10⁻²⁴ cm²), it was humorously named during the Manhattan Project - physicists joked that uranium nuclei were 'as big as a barn' at the subatomic scale. Particle physics experiments at accelerators like CERN report cross-sections in millibarns (mb), microbarns (μb), nanobarns (nb), and femtobarns (fb).
Quick Reference Table
| Circular Mils (cmil) | Barns (b) |
|---|---|
| 1 cmil | 5.067 × 1018 b |
| 2 cmil | 1.013 × 1019 b |
| 5 cmil | 2.534 × 1019 b |
| 10 cmil | 5.067 × 1019 b |
| 25 cmil | 1.267 × 1020 b |
| 50 cmil | 2.534 × 1020 b |
| 100 cmil | 5.067 × 1020 b |