Identification of insulated wires by colors according to DIN 40705 and CEI/IEC 60446

Conductor identification
The conductor identification of different conductors such as Phase conductor, Mid-point conductor, PEN-conductor and Protective conductor are distinguished by the indicating letters and colors of the conductor.
An universal international norm exists only for the green-yellow grounding conductor.
For new installation it is not allowed to use the old conductor colors.

Conductor Designation	Alphanumerical Type		Color Identification		Symbol
	old	new	old	new
Alternating Current Phase conductor 1 Phase conductor 2 Phase conductor 3 Mid-point conductor	R S T MP	L1 L2 L3 N	black red blue gray	not defined (preferred black1)) not defined (e.g. brown1)) not defined light blue2)
Direct Current Positive Negative Mid-point conductor	L + L - M	+ -		not defined not defined light blue2)
Protective Conductor		PE		green-yellow3)
Neutral conductor with protection		PEN		green-yellow3)
Grounding		E		not defined
Ground for External Voltage		TE		not defined
Load-Connecting Clamps		to L1 to L2 to L3 to N			U V W N

¹⁾Application of conductors by colors “black“ or “brown“ for internal wiring of single conductor cables
For the internal wiring of apparatus, distributor boards and equipment with the insulated single conductors, only the “black“-color is preferred. Application of other colors or combinations of two other colors are also provided, if these for the purpose of manufacturing or services are necessary. If only an additional color for the individual identification of separated conductor group is necessary, the color “brown“ is preferred
²⁾Application of the color “light blue-Where a circuit includes a neutral or mid-point conductor identified by color, the color used for this purpose shall be blue. In order to avoid confusion with other colors it is recommended to use an unsaturated color blue, called here “light blue“. Light blue shall not be used for identifying any other conductor where confusion is possible In the absence of a neutral or mid-point conductor, a conductor identified by light blue within the whole wiring system may also be used for any other purposes, except as a protective conductor.
If identification by color is used, bare conductors used as neutral or mid-wire conductors shall be either colored by a light blue stripe, 15 mm to 100 mm wide in each unit or enclosure and each accessible position, or colored light blue throughout their length.
³⁾ Application of bi-color combination “green-yellow“ The bi-color combination green-and-yellow shall be used for identifying the protective conductor and for no other purposes. Green-and-yellow is the only color combination recognized for identifying the protective conductor, according to DIN VDE 0293. The combination of the colors green-and-yellow shall be such that, on any 15 mm length of the conductor where color coding is applied, one of these colors cover at least 30% and not more than 70% of the surface of the conductor, the other color covering the remainder of that surface.
If bare conductors, used as protective conductors, are provided with coloring they shall be colored green-and-yellow, either throughout the whole length of each conductor or in each compartment or unit or at each accessible position. If adhesive tape is used, only bi-colored tape shall be applied.