fullampacity
Member
- Location
- Acton,Ca
Can someone tell me how to find circular-mils from an awg wire size. I am voltage drop formulas and its the only thing hanging me up.
Thanks guys.
Thanks guys.
finding circular-mils from awg wire size
- Thread starter fullampacity
- Start date
- Status
- Location
- Lockport, IL
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- Semi-Retired Electrical Engineer
Table 8 in the back of the NEC.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Table 8 is the right answer.
However for your amusement, here is the equation from which the conductor sizes are derived. You can use this if you need information for an odd size not in the table. Such sizes are not generally used in building wiring, but are very common in electric motors. Knowing this can also be useful if the rounding in table 8 seems to be causing a calculation error.
First diameter: The diameter in inches of an N gauge wire is D = 0.005 * 92 ^ ((36 - N) / 39)
Next the cross sectional area: The area in circular mils of a wire D inches in diameter is cm = 1,000,000 * D^2
Example:
10ga D = 0.005 * 92^((36-10)/39) = 0.005 * 92^(26/39) = 0.005* 20.379423 = 0.101897"
cm= 1000000*0.101897^2 = 10383 circular mils (tabulated value is 10380
-Jon
However for your amusement, here is the equation from which the conductor sizes are derived. You can use this if you need information for an odd size not in the table. Such sizes are not generally used in building wiring, but are very common in electric motors. Knowing this can also be useful if the rounding in table 8 seems to be causing a calculation error.
First diameter: The diameter in inches of an N gauge wire is D = 0.005 * 92 ^ ((36 - N) / 39)
Next the cross sectional area: The area in circular mils of a wire D inches in diameter is cm = 1,000,000 * D^2
Example:
10ga D = 0.005 * 92^((36-10)/39) = 0.005 * 92^(26/39) = 0.005* 20.379423 = 0.101897"
cm= 1000000*0.101897^2 = 10383 circular mils (tabulated value is 10380
-Jon
- Status