Live wire, neutral wire and ground wire. Do you know the function of these three wires?

A triangular plug , By its hot wire , Zero line , Ground wire , Do you know what these three threads do ？ And do you know where these three lines finally go ？

To find out the problem , We need to go from 220 The source of V AC power ,220 The source of V AC is the secondary side of the transformer , The output terminal of the so-called secondary test transformer , For convenience , We use this symbol to represent the secondary side of the transformer , When I was a child, I made a mistake , I think the line is connected like this .

One end of the transformer is a live wire , One end is the zero line , Reflected in this picture , The red line is the hot line , The blue line is the zero line , But then I thought it was wrong , This is alternating current , Its voltage direction is always changing , When the positive half cycle flows , The red line is the hot line , But when the alternating current flows through the negative half cycle , The blue line , This has become a hot line ？

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In this case, how to distinguish between live line and neutral line ？ In fact, it is impossible to distinguish between the live line and the zero line , In actual wiring , Generally, a line will be led out from the neutral point of the transformer and connected to the earth , The neutral point is the common point of the three coils of the transformer , We use household electricity , Just use one of the coils .

Access to the earth is to connect public points to our earth , So there is a potential reference , The potential of the blue line is the same as that of the earth at almost any time , We define the earth as zero potential , So the potential of this blue wire is zero , Know the zero line , The hot line is easy to understand , The other section of the transformer coil is the live wire .

So here comes the question , Which is the ground wire connected to ？ To understand this question , We need to know how these wires get into our home socket , When the zero line enters the community , Generally, it will be repeatedly grounded , The purpose of repeated grounding is to ensure that the zero line potential of the line entering our community is still zero , After the zero line is repeatedly grounded , It will split in two , These two wires are called PE Line and N Line .

PE The line is Protect Earthing An acronym for , It is the third corner of our socket , That is what we call a ground wire , This ground wire is actually a directly connected zero wire , Not just buried in the earth ,N yes Neutral An acronym for , It means neutral .

Because its potential remains constant , So the normal name of this wire is called neutral wire , We usually call it zero line , And this paragraph PEN It can be called protective neutral line ,L That makes sense , It is life An acronym for , Represents hot wire , Finally, a question that most people doubt , How does the ground wire prevent us from being electrocuted ？

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The ground wire is connected to the shell of the equipment , Under normal circumstances, the live wire cannot touch the shell , However, if the equipment is flooded with water or greasy dirt, the live wire and the shell are in contact , This is equivalent to a short circuit between the live line and the zero line , A large current will be generated after a short circuit , At this time, the circuit breaker in the house will be disconnected immediately , Avoid human contact with the shell for electric shock .

At this time, if we close the circuit breaker , It will also disconnect immediately , At this time, we should ask the repairman to remove the fault point , And even without a circuit breaker , It usually doesn't electrify people , Because after the hot wire contacts the shell , The potential is consistent with the earth , And the potential of our human body and the earth is the same , In this way, there will be no potential difference between the shell and the earth , So we won't get an electric shock .

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