Positive/ Negative lead what gauge?

[Richie Rich]

Originally Posted by gw204f

I'm pretty sure I used 2 AWG (don't think it was 2/0...not that I really know the difference) in my old 20' Grady when I moved the batteries under the console. That was with a 150 Merc V6.

That motor cranked so fast it nearly tore the transom off.

2/0 is big.....from small to big..14awg, 12awg,.....6awg, 4awg, 2awg, 1/0, 2/0 and so on....2 and 4awg is typical for a short run battery cable....but using the load charts is the best way to pick the right size....the distance is always measured round trip, not one way..

[reelapeelin]

I was told by a wise man from the north to use #2...so I used #2...seems to be the choice from FL to NJ...

[Destroyer]

Originally Posted by gw204f

I'm pretty sure I used 2 AWG (don't think it was 2/0...not that I really know the difference)

Just as an FYI: 2/0 is called "two-ott" (phonetically) from the British pronunciation of zero as "aught". (Pronounced the same as "you aught to be in pictures"). In American Wire gauge, sizes run from the smallest of 40 gauge, which is 3.1 thousandths of an inch, (.0031") diameter, getting larger until they reach 1 gauge which is 289 thousandths (.289") diameter. To designate larger diameters, (since there is no number smaller than 1) the next logical number was 0, or "one aught", .325", then 00, generally designated 2/0, two aught, .365", then 000, threee aught, .410, and 0000, 4/0, four aught.

The designation AWG refers to American Wire Gauge. 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 2/0 has a CM Area of 133,100.

[Kracker Jack]

You learn something new everyday!!! Thats a usefull little tidbit. Thanks DESTROYER. Good stuff.

[reelapeelin]

Originally Posted by Destroyer

Just as an FYI: 2/0 is called "two-ott" (phonetically) from the British pronunciation of zero as "aught". (Pronounced the same as "you aught to be in pictures"). In American Wire gauge, sizes run from the smallest of 40 gauge, which is 3.1 thousandths of an inch, (.0031") diameter, getting larger until they reach 1 gauge which is 289 thousandths (.289") diameter. To designate larger diameters, (since there is no number smaller than 1) the next logical number was 0, or "one aught", .325", then 00, generally designated 2/0, two aught, .365", then 000, threee aught, .410, and 0000, 4/0, four aught.

The designation AWG refers to American Wire Gauge. 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 2/0 has a CM Area of 133,100.

That's good stuff..thanks for the explanation...can you define/elaborate on Circular Mil Area...

[Destroyer]

Originally Posted by reelapeelin

That's good stuff..thanks for the explanation...can you define/elaborate on Circular Mil Area...

It's a unit of measure of the thickness of a wire. I can tell you what the unit is, but my explaination would be lousy... so rather than screwing it up here is the book defination of a Circular Mil:



What are Circular Mils?
There are many different wire gauge systems used to specify electrical wire size. In North America the two most common systems are the SAE (Society of Automotive Engineers) and AWG (American Wire Gauge). A 14 SAE wire is smaller than a 14 AWG wire and therefore, for a given insulation temperature rating, capable of carrying less electrical current.

In many ABYC tables and wire suppliers catalogs the cryptic term "Circular Mils" will be shown as part of the wire specification. Circular Mils is the term created for the measurement system devised to measure wire conductor (without the insulation) sizes in absolute terms. By specifying how many Circular Mils a 14 SAE wire has compared to the Circular Mils in a 14 AWG wire it is possible to determine the relative amounts of copper in each wire.

Unfortunately the term Circular Mils does little to clarify the situation for the average person because it is a unit of measure not used commonly and it doesn't necessarily have anything to do with circles!

One Circular Mil is a unit of area equal to that of a circle .001" in diameter (.0005" radius). The actual area of a Circular Mil is:
A =Pi x r2
A = 3.14159 x (.0005)2 inches
A = .0000007857 square inches

When wires get very large their sizes are sometimes shown as "MCM", such as 250MCM. MCM means Thousand (M) Circular (C) Mils (M). A 250MCM wire is wire with an area equal to 250 x 1000 Circular Mils
The illustrations show that a circle can be 1 Circular Mil, but a square can be one too!

A = .0000007857 square inches / A = .0000007857 square inches


Now...doesn't that make it all clear to everyone? Just remember that the more CM's there are, the thicker the wire and the more current it can carry.

[reelapeelin]

Got it...RIGHT...

The part about the thicker the wire, the more it will carry...now I got that...