3-Phase Solar Inverter: Is it Better than a Single-Phase Inverter?

FACTS CHECKED BY  Bob Smith

After researching solar and its benefits, your next step would be choosing between a single-phase and a 3-phase solar Inverter. However, you must understand certain factors before proceeding to make your choice.

First, you should consider the delivery types you use for your power supply before determining what solar inverter your home needs. This article will discuss the necessary details and help choose the right inverter type.

Single-Phase vs. Three-Phase Solar Inverter

What is a Single-Phase Solar Inverter?

Solar panel inverter 

Solar panel inverter 

It may seem plausible that if your home runs on a three-phase power supply, you’ll need a three-phase inverter for your solar system. But the reality is that single-phase models may suffice for your current conversion needs.

Also, single-phase inverters are affordable, and the simple system is ideal for connecting to single-phase power supplies. However, their simplicity also makes them compatible with three-phase connections.

Pros

Using a single-phase inverter on a three-phase power supply may sound odd, but it has advantages. For instance, if your home has a three-phase solar system, connecting a single-phase will only utilize one-third of the entire system.

Hence, you can benefit from sending the power from the remaining two phases back to the grid.

Cons

Voltage rise can negatively affect single-phase inverters sending power back to the grid. So, if the sun provides ample energy and your building demands low energy, the system will send excess voltage to the grid.

While it may not sound bad, cases like that will make the inverter trip for protection, causing it to shut down completely. Such problems are rare with a three-phase inverter.

In addition, single-phase inverters are inefficient for stand-alone solar systems with battery backup. Why? Because it will waste the power generated by the extra two phases.

What is a Three-Phase Solar Inverter?

Solar Inverter with isolated switches

Solar Inverter with isolated switches

Three-phase solar inverters are the go-to for homeowners with greater electrical demands. They are more efficient when connected to a three-phase solar or electrical system.

Three-phase solar inverters have four wires (three actives, one neutral) connecting your building to the solar system. And they supply the standard 240V or 415V for devices with greater power draw.

In addition, three-phase solar inverters can feed more power to the grid. Also, they reduce the chances of suffering from voltage rise by spreading the load through three cables instead of one.

Further, three-phase solar inverters have more efficient power delivery systems. They can distribute stable power evenly to different areas in a structure. And three-phase inverters can double down as chargers to supply constant power for solar battery charging.

Pros and Cons of Installing a Three-Phase Solar Inverter

Pros

  • Three-phase solar inverters can reduce voltage issues from the grid.
  • Also, this system can minimize inverter tripping from voltage issues.
  • Three-phase inverters will allow you to use larger solar system sizes.

Cons

  • Three-phase solar inverters are expensive investments. They can cost up to $500 more than single-phase.
  • You may experience issues with battery backup when using this inverter.

How does a 3-Phase Hybrid Inverter Work?

Illustration showing how a solar inverter works

Illustration showing how a solar inverter works

A three-phase hybrid inverter works by converting DC from a solar panel to AC for running a home. Also, they store excess solar energy in batteries and use it when required.

Then, they convert the stored AC power when the system needs the load. Some 3-phase hybrid inverters can operate without storage systems. So, they export excess solar energy to the grid. 

All three-phase solar inverters have four operation modes: grid-connected, off-grid, standby, and hybrid.

Grid-Connected Operation Mode

This mode works similarly to a regular solar inverter. But it is not grid-independent and won’t power your home when there’s an outage (since it doesn’t use batteries).

Off-Grid Mode

The inverter usually has grid isolation and connections to storage systems in this mode. Further, excess power from this mode charges the batteries and power loads without help from the grid.

Standby Mode

The standby mode functions like grid-connected inverters. But it switches to an idle mode when there’s a power outage. Fortunately, this mode can run your home, charge solar batteries, and feed excess power to the grid.

Hybrid Mode

Hybrid modes can increase self-sufficiency by storing surplus solar energy and supplying power at night.

How to Know if You Have 3-Phase Power?

Man working on a three-phase power supply

Man working on a three-phase power supply

Usually, you can find the details of your phase-type on your electrical meter. Also, you may find your meter near your home’s primary electrical switchboard.

However, there are other ways to discover your phase type, especially if you can’t decipher the meter’s information.

  • First, locate the circuit breaker labeled “Main Switch.” Then, check underneath to see the number of breakers. If it has three, your home relies on a 3-phase power supply.
  • Also, you can check if one or three wires run from the electrical transformer to your home’s street.
  • Lastly, call your DNSP for the necessary information. And the distribution network will relay your connection type with details of your Net Meter Identifier (NMI).

Note: You can find your DNSP on your monthly electrical bills. Usually, they’re the company designated for power outages and emergencies.

Rounding Up

3-phase and single-phase connection types are the most common in various standard homes. Single-phase may be an affordable and simple alternative, but they don’t offer many benefits like their three-phase counterparts.

In addition, 3-phase solar inverters negate most drawbacks of single-phase systems. Also, they help to supply more power for handling homes with higher power demand.

Do you have more questions on this topic? Please get in touch with us, and we’ll be more than happy to help.

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