Electronic – What are the errors with using only the line from a socket to power an appliance

groundingtransformer

In the diagram below, the image on the left shows how a plug is normally connected to an outlet.

The image on the right shows how the socket is replaced by a new configuration. One of the holes on the original socket is used and connected to a transformer, while the other plug is connected to the ground to create a circuit. The rationale for this is: when I used a voltmeter to connect the socket to the ground, I was able to read 110V. Clearly, there is some voltage you can draw from just one hole of the socket.

The voltage is run through a step up transformer, creating 220V. This is used to create a new socket. One of the holes is connected to the ground, while the other one is live.

This entire setup clearly looks incorrect to me, but I don't know the specific reasons why. I created a setup that looks roughly like this (using a voltage regulator for the new socket, and using a long line to plug the wire in cemented ground far away from me) and it was able to charge a power bank, but it couldn't drive an electric fan forward — the blades started spinning, but very very slowly. There were no fires or electric shocks experienced by anyone.

But, I don't understand why the setup worked in the first place. It seems to me like it shouldn't have worked at all.

My question is, What is wrong with this design, and why did it sort of work?

sockets

Best Answer

Earthing or grounding is designed to protect the users of electrical equipment by preventing dangerous voltages to appear on metal casings, etc.

schematic

simulate this circuit – Schematic created using CircuitLab

Figure 1. Building supply neutral is earthed / grounded at the supply transformer.

In most countries the electrical utility grounds one of the wires from the local step-down transformer. This "neutralises" the wire as there is now no potential relative to earth. The live wire, on the other hand, has full voltage between it and earth. This explains why your transformer will work with the neutral wire connected to earth. The fact that it works also suggests that you don't have "earth leakage" or "ground fault" protection in your house. (You should have.)

My question is, What is wrong with this design, and why did it sort of work?

It sort of worked for the reasons explained above.

There is plenty wrong with your circuit:

  • You are using ground as a return for your neutral current. Ground resistance can vary and can be high. This can give problems with your circuit.
  • Safety: if the ground wire becomes disconnected from your ground connection the wire will be live. This provides a potentially lethal shock hazard.

Additional information:

schematic

simulate this circuit

Figure 2. Supply transformer supply and earthed appliance.

Yes Live is the supply, Neutral is the return and the Earth is protection. Normally there is no current in the earth wire but if, for example, a live wire fell off inside the appliance and contacted the metal there is a risk of electrocution. Earthing the appliance prevents the case rising to dangerous voltages. In the event of a severe fault a high current may flow but the fuse will then blow, making the system safe.

Double insulated devices don't need to be earthed so a two-pin plug is adequate.

See also: In any electrical equipment having single ph 230 v ac supply ,if neutral and earth wire exchanged then what will be the consequence.

Finally, what you are doing is dangerous given your poor understanding. I recommend that you work on low-voltage circuits until your knowledge of electrical theory is improved.