vault backup: 2026-06-01 17:13:50

circular-mil.md

@@ -1,18 +1,23 @@
+---
+title: Circular Mil
+tags: []
+up: "[[electrical-construction]]"
+---
 # Circular Mil
 
 > A [**circular mil**](https://en.wikipedia.org/wiki/Circular_mil)
 > is a unit of area, equal to the area of a circle with a diameter of one mil
 > (one thousandth of an inch or 0.0254 mm).
 > It is equal to π/4 square mils...
-> 
+>
 > The area in circular mils, A, of a circle with a diameter of d mils, is given by the formula:
-> 
+>
 > $$
 > A_{\rm{cmil}} = ( d_{\rm{mil}} )^{2}
 > $$
 
 > In square mils, the area of a circle with a diameter of 1 mil is:
-> 
+>
 > $$
 > \begin{align}
 > A &= \pi r^{2} \\
@@ -23,15 +28,15 @@
 > &\approx 0.7854~\rm{mil}^{2} \\
 > \end{align}
 > $$
-> 
+>
 > By definition, this area is also equal to 1 circular mil, so
-> 
+>
 > $$
 > \rm{ 1~cmil = \frac{\pi}{4}~mil^{2} }
 > $$
-> 
+>
 > The conversion factor from square mils to circular mils is therefore 4/π cmil per square mil:
-> 
+>
 > $$
 > \rm{ 1~mil^{2} = \frac{4}{\pi} }~cmil
 > $$
@@ -40,13 +45,13 @@
 > for any given AWG (American Wire Gauge) size
 > is as follows.
 > $A_{n}$ represents the area of number $n$ AWG.
-> 
+>
 > $$
 > A_{n}=\left( 5 \times 92^{(36-n)/39} \right)^{2}
 > $$
-> 
+>
 > For example, a number 12 gauge wire would use $n=12$:
-> 
+>
 > $$
 > \left( 5 \times 92^{(36-12)/39} \right)^{2}
 > = 6530~\rm{cmil}