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#### KindOfBlue

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##### Barking Dog
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Discussion Starter · ·
I have always known wire to be measured in American Wire Gauge (AWG #4 #6, etc.), but recently learned about 1/0 and 2/0. Is this like fishing hooks (ex. 1 aught or 2 aught). Can someone explain the difference between AWG #2 and 2/0?

Thanks,
Craig

#### JHJensen

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##### Marine: Educator,Surveyor
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83 Posts
AWG wire size description

I have always known wire to be measured in American Wire Gauge (AWG #4 #6, etc.), but recently learned about 1/0 and 2/0. Is this like fishing hooks (ex. 1 aught or 2 aught). Can someone explain the difference between AWG #2 and 2/0?
Craig,

Good question! You're correct with your fish hook example.

AWG wire is described by it's Circular Mil area and the number of strands for each size wire depending on wire type used.

AWG #2 has a CM Area of 66,360 while AWG 2/00 (00) CM Area of 133,100

The attached chart from ABYC Standard E-11 AC and DC Electrical Systems on Boats.(page 68 7/08)

Here are the notes which go with the chart:
*Type 1 - Solid conductor and stranding less than that indicated under Type 2 shall not be used.
**Type 2 - Conductors with at least Type 2 stranding shall be used for general purpose boat wiring.
***Type 3 - Conductors with Type 3 stranding shall be used for any wiring where frequent flexing is
involved in normal use.
NOTE:
1. Metric wire sizes may be used if of equivalent circular mil area. If the circular mil area of the
metric conductor is less than that listed, the wire ampacity shall be corrected based on the ratio of
the circular mil areas. For comparison of conductor cross sections (AWG and ISO) see
AP TABLE 2 .
2. The circular mil area given is equal to the mathematical square of the diameter of the AWG
standard solid copper conductor measured in one thousandths of an inch.
The area in square inches= pi(circular mils)/4(1,000,000)

The circular mil area of the stranded conductors may differ from the tabulated values and is the sum
of the circular mil areas of the wires (strands) in the conductor.

John
ABYC Master Technician

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#### scottyt

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##### Registered
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basicly they ran out of numbers, could not go any lower so they made up something else, the oot system. once you get over 4/0 its all measured in circular mils

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