2023 Author: Philip Bishop | [email protected]. Last modified: 2023-05-24 22:24
- Wire marking by purpose and color
- Protective conductors.
- Zero conductor
- PEN or TN-C system
- Phase conductors
- Wire marking according to GOST R 50462-2009
- Specification marking
- Cable end marking
- The introduction of the new GOST wire designation pros and cons
- Determination of unmarked conductors at home
For the correct connection of electrical panels, it is important to follow certain rules. The main document for any electrician engaged in the installation of electrical wiring is the PUE "Electrical Installation Rules". It describes how to properly perform electrical wiring, how to calculate the cross-section of the wires, which cable or wire to use.
In addition to PUE, you need to know GOST R 50462-2009. The document describes in detail what colors and letters are allowed to be used for various wires and cables. This document came into force only in 2011.
This is a new standard that differs in many ways from the previous one. The fact is that the color marking of wires in the new GOST is in many ways contrary to the requirements of the PUE. The new GOST was developed according to European standards that differ from domestic ones. This often leads to confusion when installing electrical equipment.
Wire marking by purpose and color
The marking of wires and cables, which is applied by the manufacturer, refers to the factory marking. This is the shell color and lettering.
Color and lettering provides all the information you need. Where and in what capacity this wire should be used.
Color carries information about the purpose of the wire. In most cases, color coding is applied to the entire length of the wire. If the wire is not insulated, the marking is applied at the joints and at its ends.
According to existing standards, the following wire colors are allowed:
- the black;
- white;
- blue;
- pink;
- Violet;
- Orange;
- brown;
- red;
- yellow-green;
- turquoise.
- Gray;
Knowledge of color and letter designations significantly reduces the time of installation work, eliminates errors when connecting wires. Errors can lead to short circuits and electric shock to personnel during commissioning.
Protective conductors
For marking of protective conductors, yellow and green are used. They can be applied along or across the conductor. Moreover, in the GOST, even the ratio of colors relative to each other is determined. From 30 to 70 percent of the surface of the wire of one color, the rest of the surface of another (for every 15 mm of length). The old standard did not mention these requirements.
According to the new GOST, it is not allowed to use separately green and yellow colors!
If an uninsulated wire of a different color is used as a protective conductor, it must be identified with an adhesive yellow-green tape.
Alphanumeric designation - PE.
Zero conductor
When marking the neutral conductor of AC circuits, blue is used. It is often referred to as "neutral". The letter designation is N. In no case should you confuse "ground" with the working "0".
PEN or TN-C system
This is a grounding system in which a protective conductor and a working "0" are combined along the entire length. They are marked yellow-green. The connections and ends of the wire are blue. Reverse marking is also allowed: along the entire length - blue, at the ends and at the joints - yellow-green.
The TN-C system used to be used everywhere. Ease of installation came first. Now the safety of people has come to the fore. The four-wire system is increasingly being replaced by the five-wire TN-S system. In it, the "zero" and "protective" wires are separated.
In some projects, the separation into PE and N is done at substations. Power is supplied to the consumer by a five-core cable. But most often the separation takes place in central cabinets with an introductory machine (or disconnector).
Phase conductors
The color coding of the phase conductors in a three-phase circuit is gray, brown and black. If the circuits have a more complex configuration, markings in other colors permitted by GOST are used.
The generally accepted letter designation of the phase conductor is L. For a three-phase circuit, the designations L1, L2, L3 are used. For DC circuits, designation "L +" and "L-".
Wire marking according to GOST R 50462-2009
The table shows the main types of conductors with markings.
Specification marking
Cables and wires are marked not only for their purpose. An alphanumeric designation is usually indicated on the cable sheath, by which its technical characteristics can be determined.
Letter designations of domestic products:
1 - core material (A - aluminum);
2 - type of wire (M - assembly, K - control, etc.);
3 - insulation material (P - rubber, P - polyethylene, etc.);
4 - protective structure (B - armored with metal strips, T - for laying in pipes, etc.).
Digital designations of domestic products:
1 - number of cores (there is no first digit on a single-core wire);
2 - section;
3 - maximum stress.
Designations according to European standards:
N - VDE standard;
Y - PVC insulation;
M - assembly cable;
RG - armored protection;
C - shielded cable;
SL - control cable;
05 - voltage up to 500 V;
07 - voltage up to 750 V.
This is the most common and well-known marking for cable products.
Cable end marking
In industrial production, in telephone, telecommunication networks, another type of marking is used - marking of cable lugs.
When using cables with a large number of cores, the marking is applied when connected to junction boxes, boards, connectors. Otherwise, it will be impossible to find the required core. This is especially important when assembling electrical panels.
Cable terminations can be marked in different ways:
- with a permanent marker (cheap but not durable);
- using a self-laminating marker;
- using markers (not suitable for all types of cable);
- using marking equipment (used by professional installation organizations).
The introduction of the new GOST wire designation pros and cons
The introduction of new European standards has greatly simplified the installation of new, modern equipment. But, at the same time, a number of problems arose when servicing old electrical installations, mounted according to the old rules. It is not possible to replace the wiring on all old electrical installations. The new GOST does not require this. It is especially difficult for experienced electricians to adapt to the new rules.
Previously, phase wires could be yellow, green and red. Currently, yellow and green are used only for grounding conductors. In existing installations, the potential equalization buses are black. Now this color is used only for marking the phase conductor. Problems in determining the purpose of the conductor can lead to an accident. In order to avoid problems, priority must be given to alphanumeric marking and tire positioning. It is also necessary to closely monitor changes in regulatory documents.
Determination of unmarked conductors at home
In ordinary life, most often one has to deal with a situation where there is no marking of the household electrical network at all. All conductors in the shield can be of the same color.
All old houses have a two-wire network, i.e. without protective conductor. To determine which "zero", which "phase" is, you can use an indicator screwdriver. This tool is found in every home. When in contact with the neutral conductor, the light on the indicator screwdriver does not light up. When touched in a phase conductor, it lights up.
If your network has a ground wire, you will need a multimeter. With its help, you can determine the type of wire - earth or zero. It is necessary to set the voltage value above 220 V. We connect one contact to the phase wire. We apply the second one in turn to the remaining two wires. The neutral wire will show a value of 220 V, the ground wire will be below this value.
The main thing when performing any work related to electricity is to observe the utmost care and caution.
