Wiring Color Codes | Color Codes | Electronics Textbook - EU-Vietnam Business Network (EVBN)

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.

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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.

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

Canada: Canadian wiring is governed by the CEC (Canadian Electric Code). See Table below. The protective ground is green or green with yellow stripe. The neutral is white, the hot (live or active) single phase wires are black , and red in the case of a second active. Three-phase lines are red, black, and blue.

Canada AC power circuit wiring color codes

Function
label
Color, common

Protective ground
PG
green or green-yellow

Neutral
N
white

Line, single phase
L
black or red (2nd hot)

Line, 3-phase
L1
red

Line, 3-phase
L2
black

Line, 3-phase
L3
blue

IEC, DC: DC power installations, for example, solar power and computer data centers, use color coding which follows the AC standards. The IEC color standard for DC power cables is listed in Table below, adapted from Table 2, Cook.

IEC DC power circuit wiring color codes

Function
label
Color

Protective earth
PE
green-yellow

2-wire unearthed DC Power System

Positive
L+
brown

Negative
L-
grey

2-wire earthed DC Power System

Positive (of a negative earthed) circuit
L+
brown

Negative (of a negative earthed) circuit
M
blue

Positive (of a positive earthed) circuit
M
blue

Negative (of a positive earthed) circuit
L-
grey

3-wire earthed DC Power System

Positive
L+
brown

Mid-wire
M
blue

Negative
L-
grey

US DC power: The US National Electrical Code (for both AC and DC) mandates that the grounded neutral conductor of a power system be white or grey. The protective ground must be bare, green or green-yellow striped. Hot (active) wires may be any other colors except these. However, common practice (per local electrical inspectors) is for the first hot (live or active) wire to be black and the second hot to be red. The recommendations in Table below are by Wiles. He makes no recommendation for ungrounded power system colors. Usage of the ungrounded system is discouraged for safety. However, red (+) and black (-) follows the coloring of the grounded systems in the table.