It has sufficient current rating for the expected load in the circuit, including a margin of safety.

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. The number of devices connected to the circuit usually determines how much current will flow through the wire. AWG or American Wire Gauge is the US standard measure for the diameter of electrical conductors. The American Wire Gauge chart is based on the number of dies originally required to draw the copper down to the required dimensional size. It means the higher the AWG number is, the smaller the wire diameter is. Our Belden cables and the pairs in instrumentation cable are some of the electrical cables where the conductor size is expressed as an AWG figure. Our Tri-Rated cable, compliant with American standard UL758, can be converted to AWG cable conductor sizes if required. Increasing gauge numbers denote logarithmically decreasing wire diameters, which is similar to many other non-metric gauging systems such as British Standard Wire Gauge (SWG). However, AWG is dissimilar to IEC 60228, the metric wire-size standard used in most parts of the world, based directly on the wire cross-section area (in square millimetres, mm²). The AWG originated in the number of drawing operations used to produce a given gauge of wire. Very fine wire (for example, 30gauge) required more passes through the drawing dies than 0gauge wire did. Manufacturers of wire formerly had proprietary wire gauge systems; the development of standardized wire gauges rationalized selection of wire for a particular purpose.Select which electrical system you will be using. Either DC/AC Single-phase or AC Three-phase. That means the calculator can be a simple DC wire size calculator, all the way up to an AC three-phase tool. 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.

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. Results may change with real wires: different resistivity of material and number of strands in wire 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 This is the resistance of the conductor expressed in Ohms per metre ( W/m) and is important when determining voltage drop (see below)

This shows that 1.5mm² cable (at a current rating of 21A) will be suitable for the cable run length as the drop is well under 3% You might find it useful to read our Electrical Circuit Basics article for using the equation I = P/V where the following example is given:

conductors in raceway, cable, or earth (directly buried), based on ambient air temperature of 30°C (86°F). The n gauge wire diameter d n in millimeters (mm) is equal to 0.127mm times 92 raised to the power of 36 minus gauge number n, divided by 39: The following are some points you should consider when selecting cable for a particular application: 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.

American Wire Gauge ( AWG) is a logarithmic stepped standardized wire gauge system used since 1857, predominantly in North America, for the diameters of round, solid, nonferrous, electrically conducting wire. Dimensions of the wires are given in ASTM standard B 258. [1] The cross-sectional area of each gauge is an important factor for determining its current-carrying capacity. 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 Select the wire conductor material, either copper or aluminum. You can also use Advanced mode to set a custom material resistivity at a fixed temperature. Expressed as the number of conductors of a given diameter. So 28/0.30 means that there are 28 strands, each with a diameter of 0.30mm The most common method of referring to conductor sizes uses the cross-sectional area, expressed in mm². The following AWG metric conversion table converts AWG to mm and inches, and also lists the cross sectional area (mm2). AWG Metric Conversion Chart (AWG to mm)