Connecting the Yellow-Green Wire in a Light Switch Installation: Practical Guide

Question

Hello

I am building a layout like this:

it is to be used to turn on the light in the room, I have three wires in the box (brown, blue and yellow-green), the question is: what should I do with the yellow-green wire? leave it in the air, connect it with the other one that is already going to the lamp? if so, what about the end of this wire at the lamp?

mczapski · Answer

In the Black Hole, as in other places, the yellow-green wire is protective, i.e. PE. Theoretically, it should be connected in your case to LOAD, but to the so-called housing/luminaire. That is, in a can, combine with each other. We don't know what that light in the room means for you. If it is a hanging luminaire, it can be connected, but in practice it is rarely used as there is a low probability of electric shock to users. However, if you ask such questions, consider whether you have the ability to implement such ideas.

goldi74 · Answer

Yellow-green connect to the lamp housing. Nowhere else. But all in all, it is not necessary and rarely seen, especially in room lamps.

fis · Answer

I assume that the box in question is on the wall at the height of the President's seat and is used to install the light switch. Three wires in the box suggest that it is a two-circuit installation, i.e. for a two-key contact. On one of the wires in the box, there should be a phase potential, the other two lead to the lamp. The third wire at the lamp should be at zero potential - common to both circuits. To implement your project, just use one of the circuits, leaving the other unconnected.

seba_x · Answer

Thanks , I asked the question because I have 2 wires everywhere in my apartment , and in the new place the electricians have released 3 everywhere . In the case of, for example, a washing machine, I know that PE is for the housing, and the light bulb does not have a housing (a plastic chandelier is rather difficult to ground)

goldi74 · Answer

I don't know. What's yellow and green? Second circuit? Added after 1 [minutes]: For the bulb itself, leave the yellow-green wire alone.

fis · Answer

If my reasoning turns out to be correct, the yellow-green marking of one of the wires in the contact box results from the fact that the installer had a three-core cable with such color markings at hand and used it. I have encountered this many times.

goldi74 · Answer

Yes, but it is unacceptable.

darek_wp · Answer

Everything is correct, but as usual in life, theory has little in common with practice - unfortunately, I also encounter such cases.

Anonymous · Answer

Here, only amateurs spoke, without any knowledge, even basic electrical knowledge.
First, a colleague provided a schematic diagram that bears little relation to a physical electrical device. Just for peasant reason - only the device will be made on the basis of the scheme, which may have a sheet metal enclosure like a washing machine, or a plastic enclosure with no external conductive components.
Televisions in the 70's. The live phase was on the chaisis and the mains plug was 2 pole. And it wasn't done by mistake by the previous regime.
Why was the protective conductor not connected to the TV set, then many devices had a 3-core PE mains cord?

Now a simplified lecture on electrical, intended for people who have not read the 60364 standard. Or the electrical manual. There is such a thing as device classes. ! Class 1 and Class 2 are the most popular. A specific device has a class. The class is designed by the constructor, and its implementation is checked by the certifying institution by performing tests.
What is the PE wire for? The PE conductor is used to protect class 1 devices against indirect contact. (60,364 par 413).
What is protection against indirect contact - this is protection in the event of a puncture or destruction of the basic insulation and the penetration of voltage to external metal elements.
The metal housing does not yet determine the class of the device. Because the device may not meet the requirements for 1st class. Equally well, despite the metal housing, the device can have a 2nd class. Because inside double insulation was used.
A plastic enclosure may not meet Class 2 requirements if it has large vents for access. Or there are no internal equipotential bonding.
If there is no device, there is no discussion about the protective conductor. This old TV was a class 2 device. Because double insulation was used between the live parts and the human hand.
Bronek

fis · Answer

On behalf of myself and other amateurs I would like to thank my colleague Bronek22 for a constructive reprimand combined with a solid dose of knowledge and I am asking for more. At the same time, I recommend reading comprehension training to my colleague, and reading about the interpretation of electrical / electronic diagrams.

maruda2 · Answer

Until you write what kind of box it is and what kind of wires it is, in the sense of what is on them and where/where they go, you will not get a reasonable answer.

amores77 · Answer

Colleague Bronek22 gave a correct theoretical lecture, which does not bring much to the topic, because the author wrote that he has a lighting housing. He didn't write which one. Unfortunately, theory has little to do with practice.
Colleague grumbler2, he is probably 'most' right. First check what 'is' on this wire.
A frequent (very dangerous and incorrect) practice of installers is to use a 3-wire cable (phase (color), neutral N (blue), protective PE (yellow-green)) to implement a two-button switch. So that, for example, you can light one bulb with one button in the chandelier, and the other two with the other.

So first check if this wire is live.
1. If so - leave it, insulate it (tape, cube)
2.If not-
a) if the lighting housing is plastic (insulation class II) as in point 1
b) if the housing is metal and class I insulation, it should have an 'unpainted' thread marked with PE, or yellow-green, or with the ... earth mark. Then the PE conductor should be connected/screwed to this screw.
c) if the housing is metal, but class II insulation (doubtful, because it increases the cost of production) it will have a stamp of the device class II insulation (not as colleague Bronek22 wrote 'in double insulation'). This stamp is two squares "one inside the other".

Anonymous · Answer

This is an academic example of the harmfulness of advice on the forum - to people who are electric laymen. It is possible that the electrician used a yellow-green wire, as is done for a chandelier. And now write something to a friend who doesn't understand anything. And he doesn't know the names of the wires. He works with colors like an artist. And he doesn't even know what he's talking about. I wrote because I was criticized many times for the attitude that advice for complete laymen is harmful. Bronek

seba_x · Answer

Ok, gentlemen, nothing to be nervous about, I know a bit about electricity (certainly not as much as you do), the yellow-green PE wire is connected in the switchboard with other "PE". There is no voltage on it in the box (it's obvious), I just wanted to know what to do with it, let's assume that there will be no such device from the diagram, but only a simple light switch that normally turns on the "phase"

Connecting the Yellow-Green Wire in a Light Switch Installation: Practical Guide

try to connect it to the chandelier (enclosure) or just insulate it in a box and leave it.

kkas12 · Answer

Hello!

If the luminaire has a protective clamp, i.e. it is made in the 1st protection class, this wire should be connected to the clamp. If, however, it does not have such a clamp, i.e. it is made in protection class II or in class 0, which is no longer produced, then the protective conductor should be terminated with a clamp to prevent accidental contact with the housing, which may be metal.

The same should be done when the protective conductor is in the box in which the switch is installed, unless it is equipped with a PE terminal. It may also turn out that there are more green-yellow wires in the box. Then they should be connected together (I assume that the wires of this color are not used for other purposes).

remik_l · Answer

If the chandelier has a PE terminal, you connect it, if not, insulate it and hide it. Don't cut it off as it may be necessary in the future.

seba_x · Answer

Ok , thanks , I know everything now .

Connecting the Yellow-Green Wire in a Light Switch Installation: Practical Guide

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