We will discuss why high voltage in the home is sometimes present in the electricity system, and damages many pieces of electrical equipment.
Why is high voltage in the home electricity system
Many times, we find the appearance of high voltage in the home electrical system.
High voltage in the home is generally due to a fault in the neutral wire (the neutral wire is broken).
This is explained below:
- 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.
Problem due to neutral damage: high voltage in the home
- 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 in the 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 on high voltage in the home, please watch the videos in Hindi and English as follows:
Questions and Answers
Where the neutral wire can break
The neutral wire can break anywhere, but high voltage will come if the neutral wire from the transformer breaks.
If the neutral wire breaks in our home itself
If the neutral wire breaks within your home and you are using a single-phase supply, then no overvoltage will occur.
Voltage fluctuates when we get high voltage in the home, why
This is because the voltage in single phase depends on the load of other phases in other homes, as due to absense of a neutral wire, your home load and others home load become in series and share 400 volts.
If you want more information on this, then watch the above video.
If you like more technical videos and hand-drawn diagrams from an industry professional, then subscribe to my YouTube channel “G K Agrawal”.
I hope that you enjoyed the article on high voltage in the home
Also, the current transformer has an open secondary.
Further read, which motor is used in the electric train engine?
Also, read AC or DC, which is more dangerous.
About the Author – G K Agrawal is a retired Sr. DGM from BHEL and an Electrical & Electronics engineering professional with extensive industry and R&D experience. Through this blog and YouTube channel, he shares practical insights to help students and professionals understand real-world engineering applications. Read more about him here.
