The AWG gauge system only applies for solid, round, non-ferrous conducting wires. Keep this in mind when evaluating wire size and type for your application, as AWG doesn’t apply to stranded or non-round wires. AWG Gauge Sizes for Home Wiring, Auto Wiring, and Boat Wiring

If we wanted to wire up a light that we know has a power rating of 50W, then using I = P/V the current draw would be 50W/12V = 4.17A. This tells you that you could use a cable with a rating of 4.17A or above, however it is good practice not to design a circuit operating at the upper end of the cable's rating and so you should select a cable with some additional capacity. In this case 0.5mm² (11A) cable would be appropriate. Results may change with real wires: different resistivity of material and number of strands in wire For more information regarding wiring and cables, see our comprehensive guide here. AWG Gauge Table AWG gaugeInput what percentage voltage drop is allowable. The smaller, the better, but the limit is 5% to keep devices working properly. The n gauge wire diameter d n in inches (in) is equal to 0.005in times 92 raised to the power of 36 minus gauge number n, divided by 39:

So we want to select a cable to make sure that the voltage drop is not so large that it will cause problems, but what is acceptable and how do we calculate the right cable size to use? Well the generally acceptable voltage drop for DC circuits is around 3-4% and we can use V = IR (see Electrical Circuit Basics) to calculate the voltage drop for a cable if we know the current draw of the load and the cable's resistance per metre. Thirdly, the harder grade of PVC is more reistant to abrasion and cutting than standard PVC, offering more protection and greater reliability. There is a general rule of thumb that says if you're unsure whether the cable is large enough for the job, go up a size. This is a bit crude and not very scientific but it's not a bad rule to apply as increasing cable size can't do any harm. It has sufficient current rating for the expected load in the circuit, including a margin of safety.Anyway, enough maths - to make it easy we've developed this handy calculator which will show you the approximate voltage drop based on cable size, supply voltage, current draw and cable length. The table below provides a cross-reference between these two standards, showing the closest metric equivalents to each Gauge for cable sizes commonly used in low voltage automotive and marine applications. AWG Secondly, it has a greater working temperature range with a maximum of around 105ºC compared with around 70ºC for standard PVC. This makes it more suited to use in areas close to the engine. By definition, No. 36 AWG is 0.005 inches in diameter, and No.0000 is 0.46inches in diameter. The ratio of these diameters is 1:92, and there are 40 gauge sizes from No.36 to No.0000, or 39 steps. Because each successive gauge number increases cross sectional area by a constant multiple, diameters vary geometrically. Any two successive gauges (e.g., A and B ) have diameters whose ratio (dia. B ÷ dia. A) is 92 39 {\displaystyle {\sqrt[{39}]{92}}} (approximately 1.12293), while for gauges two steps apart (e.g., A, B, and C), the ratio of the C to A is about 1.12293 2 ≈ 1.26098.