How is the circular mil area of a round wire determined?

A circular mil is a unit of cross-sectional area that is equal to the area of a circle that is one mil (0.001 inches) in diameter. A circular mil or c.m. is therefore equal to π * ( 0.001)2 / 4 = 7.85 x 10-7 square inches.

What is circular mils per amp?

The “rule of thumb” is usually expressed in “circular mils per amp”. A circular mil is one of those weirdo American units, in this case the circular mils of a wire are equal to the square of the diameter of the wire measured in “mils” (1/1000 of an inch).

What is wire CMA?

Cir Mils or CMA = Circular Mil Area which is equal to 1/1000 (0.001) of an inch in diameter or 0.000507 MM.

What is MCM measurement?

MCM is an abbreviation for thousands of circular mils, an old measurement of wire gauge. 1 MCM = 1 kcmil = 0.5067 square milimeters. A mil is 1/1000 inch. Most wire uses AWG. MCM is also used for “million cubic meters.”

What instrument is used to measure the diameter of a wire?

screw gauge
The screw gauge is an instrument used for measuring accurately the diameter of a thin wire or the thickness of a sheet of metal. It consists of a U-shaped frame fitted with a screwed spindle which is attached to a thimble.

How do you find circular mils of a wire?

Multiply the width of the wire cross Multiply the width of the wire section in mils by the thickness of cross section in millimeters by the wire cross section in mils by the thickness in millimeters by 1.2732 and subtract the radius 1973.525 and subtract the radius factor included below.

What are circular inches?

Circular inch is area unit, symbol: [circ in]. Definition of 1 circular inch ≡ π⁄4 sq in. Area of circle with diameter of 1 inch, value exactly π × 0.00016129 ≈ 5.067075×10-4 m². Compared to square metre, circular inch is smaller unit.

How is automotive wire gauge measured?

Wire gauge is determined by the cross-section area. American replacement wire is based on the American Wire Gauge System (the larger the number, the smaller the wire diameter). By stripping off a bit of insulation, you can measure the wire package diameter with a caliper or a micrometer.