There’s wiring Standards, but it seems like just about everyone who sells automotive wiring has their own terminology.

AWG - American Wire Gauge Current Ratings

Change the temperature, if necessary. The value should be the maximum operating temperature that is expected for the wire. gives a cable cross-sectional area of 1.53 sq. mm. This corresponds to a 14 AWG cable in the Cable Size Chart above. If you can’t measure an individual strand, then measure the diameter of the bundle. It’ll at least give you an indication of the cable’s size. Then 5% of the power produced by the solar panel is simply generating heat in the cable. You might decide this is acceptable or you might decide to increase the cable size for your fridge supply.

AWG Metric Conversion Chart (AWG to mm)

So if your sparky mate says you need 5mm cable, he’s referring to ISO cable. If you buy auto cable instead, then you’ll most likely buy cable way undersized for the job… and wonder why your fridge keeps cutting out. 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. This allows for a 3% voltage drop through the cable, which is acceptable for most automotive wiring jobs (3% of 12 volts = 0.36 volts). It’s a good guide. The problem is, most of the AWG sizes they’ve listed don’t match the cross-sectional areas. At least they specify the cross-sectional area I suppose… This brand gives a lot more information, but it’s not too clear. “24 x 0.2mm” means 24 strands of 0.2mm diameter wire. Using the Cable Area Calculator above, this equates to 0.75 sq. mm cross-sectional area, which is actually just under 10% smaller than 18 AWG. So even this isn’t accurate. So use 0.36 volts for smaller cables (6 AWG/16 ISO and smaller) and 0.24 volts for large cables (4 AWG/25 ISO and larger).

4 AWG AUTOMOTIVE CABLE 170 00AMP 2040WATTS RATED 25mm2 4 AWG AUTOMOTIVE CABLE 170 00AMP 2040WATTS RATED

Say you run a positive cable from the battery to a compressor. Distance is 2 metres. If you run the negative to ground from the compressor at the compressor, then total cable length is 2 metres (plus a bit for the negative cable). Now, if we change the cable run to 20 metres, then the cable cross-sectional area needed is 15.3 sq. mm. This corresponds to 16 ISO or 4 AWG cable. d n = 0.005 i n c h × 92 ( 36 − n ) / 39 = 0.127 m m × 92 ( 36 − n ) / 39 {\displaystyle d_{n}=0.005~\mathrm {inch} \times 92 Let’s stay with this example and see what maximum current the 14 AWG cable can handle over a 20 metre cable run. We’ll use the same values we started with above, then reduce the current until the cable cross-sectional area is below 2.1 sq. mm (or 14 AWG). volts (2%) is best for large cables like battery cables 4AWG (25 ISO) or larger, carrying large currents. Why? Because they won’t heat up as much and the power loss will be lower (see below).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. Buy cable with an AWG size. This is an American Standard for cable sizes and you’ll likely get the correct cabling for the job. The point is, the only information that’s useful is the cross-sectional area of the cable. Everything else is misleading rubbish.

Wire Size Calculator

Auto cable like the SCA example above also uses the 5mm cable terminology. But auto cable is referring to the overall diameter, insulation included , not the cross-sectional area. Use the calculator below to figure out the cross-sectional area of the cable, then use the Cable Size Chart to match it to the nearest size. You’ll see in the image above, it says “Size: 5mm (2.90mm 2)”. the 5mm refers to the diameter of the cable plus the insulation. American Wire Gauge ( AWG), also known as the Brown & Sharpe wire gauge, 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.

Voltage drop gets converted to heat in the cable. The lower the voltage drop, the less heat generated.