IEC 60228 is the International Electrotechnical Commission standard for conductors used in insulated cables. Among other requirements, it defines the standard nominal cross-sectional areas used for metric cable and wire sizes.
The following values are the common IEC 60228 standard conductor sizes, expressed in square millimetres.
| 0.5 mm2 | 0.75 mm2 | 1 mm2 | 1.5 mm2 | 2.5 mm2 | 4 mm2 |
| 6 mm2 | 10 mm2 | 16 mm2 | 25 mm2 | 35 mm2 | 50 mm2 |
| 70 mm2 | 95 mm2 | 120 mm2 | 150 mm2 | 185 mm2 | 240 mm2 |
| 300 mm2 | 400 mm2 | 500 mm2 | 630 mm2 | 800 mm2 | 1000 mm2 |
Using the standard size list
These values are normally used as the starting point for cable selection, current rating calculations, voltage drop checks and short-circuit withstand checks. They also provide a useful reference when comparing metric conductor sizes with AWG and MCM cable sizes.
For resistance calculations, the actual conductor resistance depends on the conductor material, class and maximum permitted resistance values. See conductor resistance for more detail.