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What is the old and new colour code for cables ?

Wiring for AC and DC power distribution branch circuits are color coded for identification of individual wires. In some jurisdictions all wire colors are specified in legal documents. In other jurisdictions, only a few conductor colors are so codified. In that case, local custom dictates the "optional" wire colors.

IEC, AC: Most of Europe abides by IEC (International Electrotechnical Commission) wiring color codes for AC branch circuits. These are listed in Table below. The older color codes in the table reflect the previous style which did not account for proper phase rotation. The protective ground wire (listed as green-yellow) is green with yellow stripe.

IEC (most of Europe) AC power circuit wiring color codes.

Function        label   Color,  IEC Color,            old IEC

Protective earth   PE   green-yellow         green-yellow
Neutral                N   blue   blue
Line, single phase   L   brown                 brown or black
Line, 3-phase          L1   brown                 brown or black
Line, 3-phase          L2   black                 brown or black
Line, 3-phase          L3   grey                         brown or black

UK, AC: The United Kingdom now follows the IEC AC wiring color codes. Table below lists these along with the obsolete domestic color codes. For adding new colored wiring to existing old colored wiring see Cook. [PCk]

UK AC power circuit wiring color codes.

Function                    label   Color, IEC            Old UK color
Protective earth   PE   green-yellow            green-yellow
Neutral                   N   blue                            black
Line, single phase   L   brown                    red
Line, 3-phase           L1   brown                    red
Line, 3-phase       L2   black                    yellow
Line, 3-phase           L3   grey                         blue


US, AC:The US National Electrical Code only mandates white (or grey) for the neutral power conductor and bare copper, green, or green with yellow stripe for the protective ground. In principle any other colors except these may be used for the power conductors. The colors adopted as local practice are shown in Table below. Black, red, and blue are used for 208 VAC three-phase; brown, orange and yellow are used for 480 VAC. Conductors larger than #6 AWG are only available in black and are color taped at the ends.

US AC power circuit wiring color codes.


Function                                 label   Color, common                                        Color, alternative
Protective ground                 PG   bare, green, or green-yellow                   green
Neutral                                 N   white                                                  grey
Line, single phase                  L   black or red (2nd hot)                            -
Line, 3-phase                        L1   black                                                   brown
Line, 3-phase                        L2   red                                                         orange
Line, 3-phase                        L3   blue                                                        yellow


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