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Three Phase vs Single Phase

Updated: Apr 18

Electrician Servicing Electricity Cables

Regular homes typically use single-phase power, which is sufficient for most appliances and lighting. But for places with significant power demands, three-phase power becomes the hero. Instead of just one line carrying electricity, three-phase uses three lines, each carrying an alternating current. The clever part is that these currents are out of sync with each other by 120 degrees That ensures a more constant and efficient flow of power.

Who needs three-phase power?

This type of power is ideal for situations requiring a large burst of power, especially for appliances like:

  • Ducted air conditioning systems: These systems cool a whole house and require significant power to run. If you have a three-phase ducted air conditioner, you can be sure your home has three-phase power as well.

  • Bore pumps: These pumps draw water from underground sources and can be quite powerful.

  • Large workshops or industrial machinery: Places with heavy-duty equipment often rely on three-phase power for smooth operation.

How to check if you have three-phase power?

Since three-phase power caters to specific needs, there are a few ways to see if your home is equipped with it:

  • Look for the big three: Check your electrical panel. If you see three live wires (usually identified by specific colours depending on your location) along with a neutral wire, that's a strong indication of three-phase power.

  • Look for the isolation link: Introduced in 2011, isolation links or Iso-links are added to a system so that you can disconnect power to the meter safely. If you have 3 isolation links, you have three-phase power.

  • Consult a qualified electrician: If you're unsure about your home's electrical setup, it's always best to consult a licensed electrician. They can safely inspect your system and confirm whether you have three-phase power.

Will a single-phase inverter work in three phase line?

The answer is yes. The inverter will only push power generated by the solar panels into one of your home’s three phases, this will not make a difference in terms of production and consumption. You will receive the same benefits from the inverter as if you had a three-phase inverter.

How will it affect my feed-in-tarrif?

Installing single-phase inverter on a three-phase inverter will not cause any implication due to the presence of net metering which calculates the net export between the 3 individual phase. looking at an hypothetical scenario, If your system is exporting 4 kW on one phase, but buying 1 kW on each of the other phases, will you be paying for those 2 kW of incoming power (the price of which is greater than the return you see from exporting the 4kW)?

As illustrated in the diagram below, this is not the case. Polyphase metering means both your imports and exports are being monitored and summed across all three-phases, not assessed individually. In this scenario, although you exported 4 kW and imported 2 kW, you net total would amount to 2 kW export, giving you the full benefits of solar production across all three phases.

Illustration of Polyphase Metering with Single Phase Solar System


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