What Is 3 Phase Energy Meter: Its Construction, Working, And Benefits

An energy meter calculates the power consumption in a domestic and commercial setting. The calculation is commonly called 3-phase motor amps calculation. 

When talking about a Three phase energy meter in general, it uses 4 wires to supply electricity – 3 out of the 4 are phase wires, and the 4th one is the neutral wire. 

This metering method is suitable for industrial and high residential settings as it offers accurate 3-phase motor amps calculation. In India, a three-phase meter is needed only when the load is higher than 5KW or 7 KW.

A 3 phase meter is mostly used in two configurations – star and delta. The added value of two single energy meters gives the value of 3 phase motor amps calculation. 

Does it pique your interest? Would you like to know more about a 3-phase meter and whether or not you need it? If so, dive in and explore all the details!

What is the need for a 3-phase metering system?

Usually, most household appliances in India can run on a single-phase energy meter. But, if your house is bigger and you use many air conditioners, you might need a 3-phase meter to facilitate the 3-phase motor amps calculation.

As already mentioned, if the load needed at your home is higher than 7 KW, you will need a 3-phase energy meter. 

How to wire a three-phase energy meter?

We hope now you know why three-phase energy meters are more common in commercial and industrial setups: It’s because the load there is much higher than what a single-phase energy meter can handle. 

Moving on, it’s very simple to understand the basics of wiring a 3-phase energy meter. It will also help you understand the 3-phase motor amps calculation. Let’s begin with the basics.

There are a total of 8 slots in a three-phase energy meter

3 slots are used to patch the 3 phase wires bringing electricity from the grid to the energy meter. 3 more slots are used to patch the incoming phase wires to supply the electricity from the three-phase meter to the switchboard. The remaining two slots are for the neutral wire.  

Remember, when a three-phase meter is being connected, the wires have to be patched in a certain way:

If the first wire bringing the load is being connected to the 1st slot in the meter, the second slot will be used to connect that wire to the switchboard. 

To better understand things, let’s put it this way:

1. The 1st phase wire bringing electricity from the grid to the meter is connected to the 1st slot.
2. The 2nd phase wire bringing electricity from the grid to the meter is connected to the 3rd slot.
3. The 3rd phase wire bringing electricity from the grid to the meter is connected to the 5th slot.
4. The 1st phase wire, when taking electricity from the meter to the switchboard, uses the 2nd slot.
5. The 2nd phase wire, when taking electricity from the meter to the switchboard, uses the  4th slot.
6. The 3rd phase wire,  when taking electricity from the meter to the switchboard, uses the 6th slot. 
7. The neutral wire, when phasing in, uses slot number 7.
8. The neutral wire, when phasing out, uses slot number 8. 

Once this writing is understood, it’s easy to understand the basics of 3-phase motor amps calculation as well.

What are the Different Types of 3 Phase Energy meters?

There are typically two types of 3-phase meters. Let us read more about them!

• Three phases, three wire meters: This system is a combination of two single-phase meters. It uses a permanent horseshoe magnet. 

• Three phases, four-wire meter: This system consists of three coils and three aluminium discs. It is suitable for measuring the kWh in a 3-phase motor amps calculation. It functions similar to a three-phase, three-wire electric meter. 

What is the Application of a 3 Phase Meter?

The 3-phase energy meter is suitable for commercial and industrial applications. It offers efficient and accurate 3-phase motor amps calculation in areas with a heavy electric load. 

It is generally preferred for metering and ascertaining the power efficiency in factories, automation plants, solar power plants, data centres, and many other industries. 

It is applied to protect valuable equipment pieces from high voltage damages. It also monitors and provides accurate real-time power consumption data. 

It means, this metering system keeps a record of the 3-phase motor amps calculation for many months. The data can, later on, be used for analysis.

Top 4 Benefits of Using a 3 Phase Meter

Let us check some of the benefits of installing a three-phase energy meter:

1. You can use different phases for different rooms. In this way, even if one phase fails, you will still have the power supply on for the other rooms that are connected to 2 functional phases.  
2. You can distribute the load. 
3. It provides real-time and recorded power consumption data for better 3-phase motor amps calculation.

Why should you be careful when getting a 3-phase energy meter?

Although it’s not illegal to install a 3-phase meter even if your load consumption is less than 5 KW, it’s not recommended. 

If you use a 3-phase meter and your load is much less, you’ll lose money because the meter rent for a 3-phase energy meter is higher than the meter rent for a single-phase energy meter.

Conclusion

A 3 phase electric meter is essential for calculating the 3-phase motor amps calculation by heavy electrical appliances. It is recommended to use this energy meter only when your load requirement is more than 5 KW to 7 KW. 

For a load lower than this, a single-phase energy meter is sufficient and much more economically viable.

FAQs

Q. How many electric wires are present in a 3-phase meter?

There are four wires present in a 3-phase electric meter system. Three are phase wires and the 4th is a neutral wire. 

Q. What are the steps to install a 3-phase meter?

People must carefully install the 3-phase meter system to avoid accidents. 

• Firstly, the main electric power supply needs to be disconnected. 
• Afterward, the 1st phase wire coming from the grid is connected to the 1st slot in the energy meter. The 2nd one is connected to the 3rd slot, and the 3rd one is connected to the 5th slot.
• The 1st phase wire supplying current from the meter to the switchboard is connected to the 2nd slot. The 2nd wire to the 4th slot, and the 3rd wire to the 6th slot.
• The incoming neutral wire is connected to the 7th slot.
• The outgoing neutral is connected to the 8th slot.

Q. What is the safest way to install a 3-phase energy meter?

The safest way to install a 3-phase energy meter is to let experts install it. Experts have the accurate knowledge and the right tools to perform the installation safely, without any safety risk involved.