What is a 3-Phase Meter? A 2025 Guide on Types, Benefits, and Wiring Process

A 3-phase meter is an electricity meter installed by the DISCOM to record electricity consumption on a three-phase supply. It connects to three live wires and one neutral. In a 3-phase meter connection, the voltage between any two live wires is approximately 415 volts, and the voltage between a live wire and the neutral is approximately 230 volts. 

A 3-phase energy meter is usually installed in industries or businesses where power consumption is high and the phase supply is three-phase. However, it can also be installed in homes with substantial electricity consumption due to heavy-load appliances, such as multiple air conditioners, water heaters, pumps, and large kitchen equipment, all running simultaneously. In India, a 3-phase electric meter is usually needed at homes when power consumption exceeds 5 kW.  

One of the biggest benefits of having a 3-phase meter connection is that even if the power supply is cut off in one phase, the electricity supply continues in the other two phases. It means that only those appliances or rooms connected to the phase that’s down will stop working. This feature makes three-phase energy meters significantly more reliable than a single-phase electricity meter.

In India, most older electricity meters are being replaced by smart meters, and a three-phase meter is no different. A smart meter comes in both single-phase and three-phase configurations.

In this blog, we will explain what a 3-phase meter is, its benefits, types, cost, and how it differs from a single-phase electricity meter. We will also demonstrate how installing an on-grid rooftop solar panel system for homes, housing societies, and commercial complexes can help reduce electricity bills, which are rising by 3-6% annually.

TL;DR Summary Box: Who Can Install a 3-Phase Meter Connection?

Installing a 3-phase meter connection in India is strictly regulated and performed by authorized personnel from your local electricity distribution company (DISCOM). Consumers are not allowed to install or tamper with any electricity meter themselves. The DISCOM fixes all meters, including sub meters, prepayment meters, and smart meters, in most states.

A licensed electrician can carry out internal wiring and load management, but the DISCOM always installs the meter itself. Even applications for upgrading from a single-phase to a 3-phase meter connection must be submitted directly to the DISCOM for approval.

Here are the main topics covered in this blog in detail:

What is a 3-Phase Meter?

A 3-phase meter is an electronic meter that’s used to monitor and record electricity consumption in three-phase connections, which deliver electrical energy through three alternating current (AC) waveforms placed 120 degrees apart. It’s an advanced metering system that tracks the power usage across all three phases simultaneously.

Here are the main components of a three-phase energy meter:

• Voltage measurement circuits: They monitor the voltage of each phase (L1, L2, and L3).
• Current measurement systems: They track the flow of electricity, either directly or through current transformers (CTs).
• Processing unit: It calculates the total energy consumed by combining the voltage and current data from all phases.
• Display interface: It’s the screen that shows real-time readings and total electricity consumption in kWh. 
• Communication modules: These are present in smart meters, allowing the meter to send the unit consumption data remotely to the electricity company.
• Neutral wire connection: It’s the fourth wire that acts as the return path and allows single-phase appliances to work on a three-phase supply.

The 3-phase meter continuously monitors voltage and current on each phase and multiplies these values to calculate power consumption. This data is then integrated over time to provide accurate kilowatt-hour (kWh) readings for generating the electricity bill.

What are L1, L2, and L3 in a 3-Phase Energy Meter?

L1, L2, and L3 are the three individual phase lines in a 3-phase energy meter that carry alternating current 120 degrees apart from each other. This spacing lets the system deliver power smoothly and makes it easier to share the load.

Here’s the wiring information that’s crucial to understand three-phase electric meters:

• L1 or Phase 1: It’s also referred to as R-phase (Red).
• L2 or Phase 2: It’s also known as Y-phase (Yellow).
• L3 or Phase 3: It’s commonly called B-phase (Blue).
• Neutral (N): This is the fourth wire that serves as the return path.
• Phase order matters: The order of L1, L2, and L3 should be consistent from the incoming supply to the outgoing load. The wrong order can reverse the rotation of three-phase motors and trigger errors on certain meters.
• Phase separation: The three phases are 120 degrees apart. That is what makes three-phase power balanced and efficient.
• Load balancing is important: Heavy appliances should be evenly distributed across L1, L2, and L3 to prevent any single phase from being overloaded. This maintains a more stable voltage and reduces the likelihood of tripping.
• Neutral may be absent in some systems: Large industrial feeders can be three-wire without neutral. Most homes and small businesses use four-wire systems with a neutral present.

When is a Three-Phase Meter Needed?

A three-phase meter becomes necessary when electrical load requirements exceed the capacity of single-phase systems, or when you operate heavy-duty equipment that demands stable and high-capacity power. In India, this is common in homes with a connected load exceeding approximately 5 kW, as well as in commercial properties, industrial facilities, and data centers. 

Let’s discuss some specific scenarios and applications where having a 3-phase meter connection makes most sense:

• Multiple air conditioners: If you run central HVAC or several split ACs simultaneously, a three-phase supply can distribute the load across phases, keeping the voltage steadier.
• Electric-vehicle charging: Fast chargers and multiple home or fleet chargers draw high current. Three-phase meters help charge faster and reduce stress on a single phase.
• Workshop and fabrication tools: CNC machines, welders, compressors, and larger motors start and run more efficiently on a 3-phase meter connection, with fewer trips and less voltage drop.
• Commercial kitchens: Ovens, fryers, dishwashers, and cold rooms often run together. A three-phase energy meter connection safely and efficiently handles the combined load.
• Elevators and lifts: Lift motors are designed for three-phase operation. A three-phase electric meter is usually mandatory for smooth starts and safe braking.
• Data rooms and server racks: UPS systems and dense IT loads benefit from balanced phases and better power quality.
• On-grid solar systems for homes with high power consumption: As previously discussed, every DISCOM has a limit on the amount of load that can safely run on a single-phase supply. If your home exceeds the limit set by your utility company, you will have to install a 3-phase electric meter at your home to run a rooftop solar system.
• On-grid rooftop solar systems for housing societies: Large on-grid solar inverters are usually three-phase. DISCOMs usually also mandate a 3-phase meter for solar net metering as the system size increases.
• Commercial rooftop solar systems: Larger on-grid inverters in shops, offices, and small factories are usually three-phase. A three-phase connection and a bidirectional net meter will enable you to export excess solar energy to the grid and distribute the generation across all phases. 
• Upgrading sanctioned load: When you apply to increase sanctioned load beyond what your DISCOM caps for single-phase loads, they may require you to move to a three-phase energy meter.

What Are the Different Types of 3-Phase Electric Meters?

3-phase electricity meters can be classified in two ways:

• Based on technology used inside the meter: These include electromechanical meters, electronic digital meters, smart meters, whole-current meters, and CT-operated meters.
• Based on wiring configuration: These are three-wire meters and four-wire meters used for Delta and Star configurations, respectively.

Before we can explain the details of all types of three-phase electric meters in detail, here’s a snapshot table comparing them:

Now, let’s understand a bit about all types of three-phase meters in detail:

• Electromechanical meter: This is the old rotating-disc meter. It still works in some old homes but is less accurate and is being phased out. It’s no longer installed at new properties.
• Electronic digital meter: This three-phase energy meter uses digital circuits to measure each phase. It is compact, accurate, and often shows multiple readings on an LCD.
• Smart meter: This is a digital meter with built-in communication modules. It sends readings to the DISCOM, supports prepaid or postpaid billing, and is used for net metering with grid-connected solar systems.
• Whole-current meter: This is a subtype of digital meters, where the load current passes directly through the meter. It is used for lower-capacity three-phase connections in homes and small businesses.
• CT-operated meter: This is also a subtype of digital meters that uses current transformers to measure very large currents safely. It is common in malls, factories, and data centers.
• Three-wire meters for delta configuration: This three-phase meter connects only the three phases and does not have a neutral. It is used where only three-phase machines are in operation, such as large motors in industrial plants.
• Four-wire meters for star configuration: This 3-phase meter connects three phases and a neutral. It allows you to run both normal 230-volt single-phase appliances and 415-volt three-phase equipment. This is the usual choice for homes, offices, shops, and housing societies.

How Are 3-Phase Meters Wired?

A 3-phase meter can be wired in two ways. The first is the star setup, which uses three phase wires and a neutral. This is what most homes, shops, and offices in India use, as it supports both single-phase and three-phase appliances. The second is the delta setup, which uses only the three phase wires and no neutral. This is common in industries, where only three-phase machines run. 

It’s crucial to remember that DISCOM officials are responsible for installing a 3-phase meter, and you cannot install it yourself. Here are the common steps that certified personnel use when they wire three-phase energy meters in the star setup:

• Step 1 – Bring in the supply cables: The electricity board provides three incoming phase wires (L1, L2, L3) along with one neutral wire. An earth wire is also present for safety, though it is not connected to the meter itself.
• Step 2 – Phase wires are connected to the meter: Each phase is connected to its respective terminal on the meter: L1, L2, and L3. The neutral is connected to the neutral terminal. This allows the meter to track current and voltage separately for each phase.
• Step 3 – Outgoing connections are taken to the distribution board: From the output side of the meter, wires are carried to the main distribution board in the building. All electricity flows through the meter first. Hence, consumption is recorded before power is distributed to appliances.
• Step 4 – Correct phase sequence is maintained: The order of L1, L2, and L3 must remain the same on both input and output sides. This ensures that motors, lifts, and other three-phase equipment operate in the correct direction, preventing damage.
• Step 5 – The load is properly distributed across the three phases: Electricians distribute heavy appliances across L1, L2, and L3 to avoid overloading a single phase. For example, one AC may run on L1, a water pump on L2, and a geyser on L3.
• Step 6 – Special case for CT-operated meters: In large commercial or industrial sites where current is very high, current transformers (CTs) are installed on each phase. The CTs reduce the current to a safer level, and the 3-phase meter measures the scaled-down version of the current, rather than the full load directly.

What is the Cost of a 3-Phase Electric Meter in India?

The cost of a 3-phase electric meter in India varies from one DISCOM to another, from state to state, from city to city, and depending on the type of meter. For instance, the cost of installing a 3-phase smart meter for rooftop solar in MP is ~Rs. 7,000*, and the same meter in Gujarat can cost ~Rs. 4,000*. 

*Please note: The cost of a 3-phase electric meter in India varies widely across states and DISCOMs and can change without notice. The figures shared here are indicative only and may differ by city, sanctioned load, meter type, make/model, stock, brand, and current DISCOM policy. Always confirm the latest price, inclusions/exclusions, and process with your local DISCOM. This information is not a quotation or a commitment to supply.

What is the Difference Between a Single-Phase and a Three-Phase Meter?

A single-phase meter monitors electricity through one alternating current wave using just two wires, one phase and one neutral. In contrast, a 3-phase meter tracks power across three alternating current waves, 120 degrees apart, usually using four wires (three phases and one neutral).

• Single-phase meters: They measure electricity consumption from a single alternating current that flows through one live wire and returns through the neutral wire. The AC power pulses in a sine wave pattern, creating momentary power drops as the current alternates direction. This results in less stable power delivery, especially under heavy loads. 
• 3-phase energy meters: Three-phase meters simultaneously measure electricity from three separate alternating currents that are offset by 120 degrees from each other, creating continuous and overlapping power waves. When one phase reaches its peak, the other two are at different points in their cycles, ensuring constant power delivery without the dips experienced in single-phase systems. The meter monitors voltage and current across all three phases (L1, L2, L3) independently, and has a neutral wire. 

Let’s check out how these two meters truly differ from each other:

What Are the Benefits of a 3-Phase Meter?

3-phase meters have a higher load handling capacity, and they deliver smoother power with minimal voltage fluctuations. Most importantly, if one phase fails, the load connected to the other two phases remains unaffected as the electricity supply on those two phases continues.  

Let’s check out all the benefits of three-phase electric meters in detail:

• Higher load capacity: A 3-phase meter connection carries more power comfortably. It suits homes with power consumption higher than 5 kW and scales all the way to very large sites.
• Smoother power under heavy use: Because the three currents are 120 degrees apart, their peaks do not line up. The result is a smoother supply when several heavy appliances start and stop.
• Keeps more things running during a phase fault: If one phase goes out, only the appliances/loads on that phase stop. The other two phases can continue to supply power to the rest.
• Fewer trips: You can spread heavy appliances across L1, L2, and L3. This avoids pushing one phase too hard and reduces the frequency of random breaker trips.
• Improved voltage stability: Balancing loads across three phases reduces voltage drop on any single phase. As a result, lights flicker less.

How to Reduce a 3-Phase Electricity Bill?

The most effective way to reduce your electricity bills, whether you have a single-phase or 3-phase meter connection, is by installing an on-grid rooftop solar system to meet all your power requirements. Going solar can reduce homeowners’ electricity bills by up to 90%. Many users also report getting zero bills after installing on-grid solar systems. 

2025 seems to be the best time to install on-grid rooftop solar systems because the government is also offering a subsidy on residential installations: 

• Homeowners receive a subsidy under PM Surya Ghar Muft Bijli Yojana: You can get a maximum subsidy of up to Rs. 78,000.
• Housing societies receive a subsidy under PM Surya Ghar Muft Bijli Yojana: You can receive a maximum subsidy of up to Rs. 90 lakh.

This subsidy assistance is only offered when residential customers install an on-grid rooftop solar system. It means you won’t be able to claim this financial help if you instead go for off-grid solar systems, ground-mounted solar systems, or commercial rooftop systems.  

Out of the three main types of solar systems, on-grid solar systems are the most cost-effective. Unlike off-grid and hybrid solar systems, on-grid systems do not require lithium batteries to store excess solar energy generated by the solar panels during the daytime. Any excess current can be sent to the grid for storage. 

You can use SolarSquare’s free solar energy estimator calculator to get an idea about the cost of installing an on-grid solar system in your city, vs the money this system will save in 25 years of its life by making your electricity bills zero.

For demonstration purposes, we have created this table comparing the cost of a 5 kW solar system in India with the savings it offers in 25 years: 

*Please note: The 5 kW solar panel price in India with subsidy mentioned above is indicative as of 1st October 2025 for the SolarSquare Blue 6ft variant. The actual solar plate price depends on your DISCOM charges, city, product variant opted for, panel type, inverter type, mounting structure height, type of after-sales service, savings guarantee, roof height, etc. Prices are subject to change. Additionally, when calculating savings, we have considered an annual tariff escalation of 3% and an annual degradation of 1%. The actual final savings from a 5 kW solar system depends on the types of solar panels you’ve installed and their efficiency, intensity of sunlight your rooftop receives, orientation of the panels and tilt angle, the pollution level and weather conditions in your city, the temperature, shadow on the roof, impact of dirt/dust, and how well you maintain your panels after installation.

Conclusion

A 3-phase meter is used when power needs are high. It’s commonly used in factories, shops, offices, and bigger homes. It measures electricity on three separate lines and maintains a steady supply when multiple appliances are in use. 

If you’re someone eager to reduce your 3-phase electricity bills, installing a solar system is the way forward. For any information regarding that, you can book a free solar consultation call with SolarSquare today.

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FAQs

Q1. Can I run a 3-phase meter connection at home?

Ans. Yes, you can. Many bigger homes in India use a 3-phase connection, especially when power use crosses around 5 kW with multiple ACs, pumps, or other heavy appliances.

Q2. Does 3-phase electricity cost more?

Ans. No, the unit rate for electricity is the same whether it’s for a three-phase connection or a single-phase connection.

Q3. Do I need 3-phase power in my house?

Ans. You need it only if your home has a high electricity demand, for example, if you use several ACs or plan to install a large rooftop solar system. For most homes, a single-phase system is sufficient.

Q4. Can I use a 3-phase meter for single-phase?

Ans. Yes, single-phase appliances can run on a 3-phase meter. In a star configuration, you simply connect them between one phase and the neutral.

Q5. How do I know if my meter is 3-phase?

Ans. Look at the meter display or the label. A 3-phase meter usually shows readings for L1, L2, and L3, and it has four input terminals instead of two.

Q6. What are the applications of a three-phase energy meter?

Ans. They are used in homes with heavy loads, shops, offices, factories, commercial kitchens, elevators, large pumps, data centers, and in solar systems with big inverters.