BASIC wire question
know..this may seem very elementary to you folks but I will admit, Im kind of confused about some copper/aluminum wire gauges. I know that the smaller the #, the thicker the wire but what exactly is 2/0 or 3/0 or even 4/0 wire? What is 2-2-2 or 3-3-3-1 wire? Please don’t laugh at this basic question but I don’t understand why #2 wire is rated at 115A at 75 degrees whereas 2/0 is rated at 175A at 75 degrees. How can 2 wire gauges of #2 have different ampacities?
What exactly does the # after the slash mean?
Increasing gauge numbers give decreasing wire diameters, which is similar to many other non-metric gauging systems. This is derived from the fact that the gauge number is related to the number of drawing operations that must be used to produce a given gauge of wire; very fine wire (for example, 30 gauge) requires more passes through the drawing dies than does 0 gauge wire.
The # after the slash for wire size, 1/0, 2/0, 3/0, and 4/0 is always a zero, pronounced “aught”, and means the wire size is X number of zeros, where X is the number before the slash. For example, 2/0 is pronounced “two-aught”, and is technically size 00 in the real table of AWG sizes. You will never hear someone call that wire size “zero-zero”, or in the case of size 4/0 (really size 0000) you will never hear it as size “zero-zero-zero-zero” – that wouldn’t sound good!
There are 40 wire sizes in the American Wire Guage (AWG) system, from #36 (smallest) to size 0000 (largest), a.k.a. 4/0 because it is the size known as having four zeros. So we have sizes from #36, #35, #34, #33, etc to #4, #3, #2, #1, 0 aka 1/0, 00 aka 2/0, 000 aka 3/0, and 0000 aka 4/0.
By definition, solid No. 36 AWG is 0.005 inches in diameter, and No. 0000 is 0.46 inches in diameter, and each larger size is 1.1229X the size of the previous one.
Clear as mud?
