Input a value for the current of the system. This figure should be the peak current so that the cable can be sized for the worst case. For more information regarding wiring and cables, see our comprehensive guide here. AWG Gauge Table AWG gauge This problem is overcome by manufacturing the core from many small diameter strands of copper wire to make up the desired cross-sectional area, rather than using a single wire. This type of cable is (unsurprisingly) known as 'stranded' cable and provides much more flexibility, which means improved resistance to work hardening making it better suited to use in vehicles. The difference in cross sections is shown in the diagram below: 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.

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. Input what percentage voltage drop is allowable. The smaller, the better, but the limit is 5% to keep devices working properly.Firstly, it is lighter, meaning that there can be significant weight savings in large wiring harnesses and this is one the main drivers behind it having now been adopted by almost all vehicle manufacturers for their electrical systems. 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%

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 wire size chart below shows allowable ampacities of insulated conductors rated up to and including The n gauge wire resistance R in ohms per kilofeet (Ω/kft) is equal to 0.3048×1000000000 times the wire's resistivity ρ inSecondly, 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. conductors in raceway, cable, or earth (directly buried), based on ambient air temperature of 30°C (86°F). 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 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. AWG is also commonly used to specify body piercing jewelry sizes (especially smaller sizes), even when the material is not metallic. [2] Formulae [ edit ]

Expressed in mm² and describes the tota l cross sectional area of the copper conductor. You will sometimes see cable described as 1mm or 2mm cable without the ² sign but it is important to note that this does not mean the diameter of the cable. This can often lead to confusion so just remember that the main specification for a cable will be its conductor's cross-sectional area and cable will never be referred to by its diameter alone. In Europe, metric sizes are used for stranded cableand are expressed as the total cross sectional area of the conductors together with the number of strands and their diameter. For example, a cable specified as 2.0mm² 28/0.30 indicates that it has a total conductor cross sectional area of 2.0mm² and is made up of 28 individual strands, each of 0.3mm diameter. All elements of an electrical circuit have resistance, including electrical cable, which means that there will be energy loss in the form of voltage drop experienced along the length of the cable. Just as a bulb converts electrical energy into heat and light due to its resistance, and so induces a voltage drop, a copper conductor has resistance and will convert some of the energy it conducts, causing a voltage drop in the same way. The difference is that voltage drop across a bulb (or other load) is useful as that's what makes it work, but voltage drop along cable and other passive parts of a circuit is not desirable as it's not a useful conversion of energy.

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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: Each component or appliance connected to a circuit will have a current draw associated with its operation and it is important that the cable supplying power to these is capable of carrying the normally expected current, plus a margin of safety. If it is not capable then it is likely to result in the cable becoming hot and potentially catching fire. Although fuses are used in the circuit to protect the cable, the cable itself should be of an adequate rating to prevent this over-heating occurring under normal circumstances. 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: In most situations the detrimental effects can be minimised by using shrink sleeving, sealed connectors, adhesive lined terminals, protective gels etc. to keep moisture out, but in some applications where the environment is particularly aggressive, for example marine use, it might be preferable to use cable with tinned conductors. This is simply where the standard plain copper conductor has has a layer of tin applied before being sheathed in the insulation.Tin doesn't react in the presence of moisture, yet retains good conductivity, and so improves long-term performance of the cable. The downsides are that it is slightly more expensive and there is a more limited range of sizes and colours available compared with plain copper. Earth braid straps that have no insulating layer are typically tinned for protection as a matter of course. 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:

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. The following are some points you should consider when selecting cable for a particular application: 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. The n gauge wire resistance R in ohms per kilometer (Ω/km) is equal to 1000000000 times the wire's resistivity ρ in While the AWG is essentially identical to the Brown & Sharpe (B&S) sheet metal gauge, the B&S gauge was designed for use with sheet metals as its name suggests. These are functionally interchangeable but the use of B&S in relation to wire gauges, rather than sheet metal gauges, is technically improper.If this AWG metric calculator doesn't provide you with the information you need, please get in touch with the technical experts of The Cable Lab who will be pleased to answer your questions or calculate the appropriate AWG/metric size for your installation. This is the resistance of the conductor expressed in Ohms per metre ( W/m) and is important when determining voltage drop (see below) The AWG tables are for a single, solid and round conductor. The AWG of a stranded wire is determined by the cross-sectional area of the equivalent solid conductor. Because there are also small gaps between the strands, a stranded wire will always have a slightly larger overall diameter than a solid wire with the same AWG. Low voltage automotive and marine cable is available in different materials/constructions and the following table gives a brief overview: Material