We will discuss why high voltage is sometimes present in the electricity system of the home. and damages many pieces of electrical equipment.
Why is high voltage in the electricity system of the home
Many times, we find the appearance of high voltage in our electrical system at home.
High voltage at home is generally due to a fault in the neutral wire (the neutral wire is broken).
This is explained beow:
- The Electricity office installs a transformer near a residential area to convert 11kv or 33kv to a 415 volts 3-phase AC supply.
- There is no single-phase supply. Only 3 phase supply comes to the transformer.
- 3 phase supply has three phases called R, Y, and B, along with a neutral wire.
- These four wires can form 3 numbers of single phase system. There are R and neutral, Y and neutral, and B and neutral.
- So about 33 percent houses get a single-phase supply from R and neutral.
- About 33 percent house get single phase supply from Y and neutral.
- About 33 percent house get single phase supply from B and neutral.
- Now, some time Neutral wire gets broken or damaged.
- Now, if we have an electrical supply from R and neutral, and if neutral is damaged, then the return path may be Y or B phase. For discussion, we will take the Y phase only to make the explanation simple.
- R and Y phases are feeding two different houses.
- So two homes are connected in series to the R and Y phase.
- Voltage between R and Y is 400 volts.
- Both houses will share some voltage in series. Total voltage will be 400 volts, not 230 volts.
- This sharing of voltage will depend upon the load in each house.
- It is like sharing voltage between two series resistors.
- As the load in one house will change, so voltage sharing.
- Hence maginudude of the voltage will also change in addition to high voltage.
- This way, we get high voltage at home, but with a changing magnitude.
We should install some kind of overvoltage protection unit at home to protect our equipment.
For more detailed information, please watch videos in Hindi and English as follows:
Also, the current transformer with an open secondary.
Further read, which motor is used in the electric train engine?
Also, read AC or DC, which is more dangerous.
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About the author – G K Agrawal B.Sc and B.Tech (from HBTU Kanpur), Retd. Sr DGM Design (BHEL), the inventor of patents, has lifelong industry experience in the electrical and electronics design field of R&D. He worked for BHEL. He shares his experience and knowledge on blogs and YouTube. Read the profile here.
