Electrical wiring color code


UNE 21089 regulates the color of conductors insulation, to differentiate when handling, because each wire has got a role. Therefore is not an aesthetic issue. Thus, the regulation states:

  • Green or green and yellow earthing. Cables are saving us from electrocution. Formerly, the gray or white wires were used, but to avoid confusion, began to be used bicolor, being more striking.
  • Clear blue to the neutral conductor, for portable tools and electrical appliances. They are also ground connections, but only connected to the transformer so as to bring the energy back. Until 1970 red was used.
  • Black, brown or gray for phase cable. Green was used previously. Although in reality, this conductor can be any color, while being different to the neutral or ground. In general, the most used are: black, red and dark blue.


Following, some additional clarifications regarding other colors:

  • Colored wires with a line (called “guide”) are neutral cables, to identify the color cable to be paired up.
  • Black cables are charge or current conductors, because they carry the electricity to the device to work.
  • Colored wires: All of them, except those with a stripe, are power cables. The most common is red, because it allows quick identification when there are many cables. Using the colored wires is easier to identify the location of each of them.

That is all today about colors. Any missing?