is important for faster and more correct installation of electrical distribution devices, ease of repair and elimination of errors. The colors of wires in electrics are regulated by regulatory documents (PUE and GOST R 50462-2009).
Why color coding of wires and cables is needed
Installation and maintenance work in electrical installations is not only about reliability, but also about safety. Full error elimination is required. For these purposes, a system of color designations for core insulation has been developed, which determines what color the wires are phase, zero and earth.
According to the PUE, the following colors of current-carrying conductors are allowed:
- red;
- brown;
- black;
- gray;
- white;
- pink;
- orange;
- turquoise;
- purple.
The list below contains many wire color options, but there are not several colors that are used only to indicate:
- blue color and its shades - working neutral wire (neutral - N);
- yellow with green stripe - protective earth (PE);
- yellow-green insulation with blue marks on the ends of the cores - combined (PEN) conductor.
It is allowed to use conductors with green insulation with a yellow stripe for grounding, and for combined conductors of blue insulation with yellow-green marks at the ends.
The colors must be the same in each circuit within the same device. Branch circuits must be carried out with the same colored conductors. The use of insulation without differences in shades indicates a high installation culture and greatly facilitates further maintenance and repair of equipment.
Phase color
In cases where the installation of the electrical installation is carried out using rigid metal tires, the tires are painted with indelible paint in the following colors:
- yellow - phase A (L1);
- green - phase B (L2);
- red - phase C (L3);
- blue - zero bus;
- longitudinal or inclined stripes of yellow and green color - ground bus.
The color of the phases must be preserved within the entire device, but not necessarily on the entire surface of the tire. It is allowed to mark the phase designation only at the connection points. On the painted surface, you can duplicate the color with the symbols “GZK” for the paint of the corresponding colors.
If the tires are not available for inspection or work when voltage is present on them, then it is allowed not to paint them.
The color of the phase wires connected to the rigid busbars may not match them in color, since the difference in the accepted designation systems for flexible conductors and rigid stationary distribution busbars is visible.
Neutral color
What color is the neutral wire, the GOST standards stipulate, therefore, when looking at the installation of the power plant, the question should not arise whether the blue wire is a phase or zero, since the blue color and its shades (blue) are taken to indicate neutral ().
Other neutral core colors are not permitted.
The only acceptable use of blue and blue insulation is the designation of the negative pole or midpoint in DC circuits. You can't use this color anywhere else.
Ground wire color code
Regulations specify what color the earth wire is in electrical installations. This is a yellow-green wire, the color of which stands out well from the rest of the wires. It is allowed to use wire with yellow insulation and a green stripe on it, or it can be green insulation with a yellow stripe. No other color of ground wire is permitted, nor are green/yellow conductors permitted to be used in circuits where voltage is present or may be energized.
The listed marking rules are observed in the countries of the post-Soviet space and in the EU countries. Other states mark the cores in a different way, which can be seen on imported equipment.
Basic colors for marking abroad:
- neutral - white, gray or black;
- protective earth - yellow or green.
The standards of a number of countries allow the use of bare metal without insulation as a protective ground.
Ground wires are switched on prefabricated non-insulated terminals and interconnect all metal parts of the structure that do not have reliable electrical contact with each other.
Coloring in the network 220V and 380V
Installation of one- and three-phase electrical networks is facilitated if the wiring is made with multi-colored wire. Previously, flat two-core white wire was used for single-phase apartment wiring. During installation and repair, in order to eliminate errors, it was necessary to ring each core separately.
The release of cable products with colored cores in different colors reduces the complexity of the work. To designate phase and zero in single-phase wiring, it is customary to use the following colors:
- red, brown or black - phase wire;
- other colors (preferably blue) - neutral wire.
Phase marking in a three-phase network is slightly different:
- red (brown) - 1 phase;
- black - 2 phase;
- gray (white) - 3 phase;
- blue (cyan) - working zero (neutral)
- yellow-green - grounding.
Domestic cable products comply with the core color standard, so a multi-phase cable contains differently colored cores, where the phase is white, red and black, zero is blue, and the ground is yellow-green conductors.
When servicing networks mounted according to modern standards, you can accurately determine the purpose of the wires in junction boxes. If there is a bundle of multi-colored wires, the brown one will necessarily be phase. The neutral wire in the distribution boxes has no branches and breaks. The exception is taps to multi-pole switching devices with a complete opening of the circuit.
Coloring in DC networks
For DC networks, it is customary to mark the conductors connected to the positive pole in red, to the negative - in black or blue. In bipolar circuits, blue-tinted insulation is used when marking the midpoint (zero) of the power supply.
There are no standards for color markings in multi-voltage circuits. What color are the plus and minus wires, what voltage is in them - this can only be determined by decoding the device manufacturer, which is often given in the documentation or on one of the walls of the structure. Example: computer power supply or car wiring.
Automotive wiring is characterized by the fact that in it the circuits with a positive voltage of the on-board network are red or its shades (pink, orange), and those connected to ground are black. The rest of the wires have a specific color, which is determined by the car manufacturer.
Letter designation of wires
Color marking can be supplemented with letters. Partially, the symbols for designation are standardized:
- L (from the word Line) - phase wire;
- N (from the word Neutral) - neutral wire;
- PE (from a combination of Protective Earthing) - grounding;
- “+” – positive pole;
- “-” – negative pole;
- M is the midpoint in DC circuits with bipolar power.
To designate the protective earth connection terminals, a special symbol is used, which is stamped on the terminal or on the instrument case in the form of a sticker. The ground symbol is the same for most countries in the world, which reduces the likelihood of confusion.
In multi-phase networks, the symbols are supplemented by the phase serial number:
- L1 is the first phase;
- L2 - second phase;
- L3 is the third phase.
There is marking according to old standards, when the phases are denoted by the symbols A, B and C.
A deviation from the standards is the combined phase designation system:
- La is the first phase;
- Lb is the second phase;
- Lc is the third phase.
In complex devices, there may be additional designations characterizing the name or number of the circuit. It is important that the markings of the conductors match throughout the entire circuit where they participate.
Letter designations are applied with indelible, clearly visible paint on the insulation near the ends of the cores, on pieces of PVC insulation or a heat-shrinkable tube.
Connection terminals may have printed signs that indicate the circuits and polarities of the power supply. Such signs are made by paint, stamping or etching, depending on the material used.