What is 3 Phase Power?

Need more Power? Need to upgrade your power supply to 3 Phase Power?

Need to run industrial machinery, power large motors or heavy loads?

Is your current air conditioning system costing you a fortune to run on single phase?

Does your 3 phase factory require an upgrade, due to an insufficient power supply?

How does 3 Phase Power work?

Electricity is either connected at 230 or 240 volts (single-phase, which accounts for the majority of domestic situations), or 400 and 415 volts (three-phase). A 3 phase system is much more efficient for high-capacity installations. The increase in power efficiency reduces the amount of power distribution equipment (circuit breakers, PDUs, cabling) that must be installed. This then reduces installation and labour costs.

A 3 phase circuit combines three alternating currents of the same frequency, each 120 degrees out of phase with each other. This produces three separate ‘waves’ of power. The power in a 3 phase power supply never drops to zero, but in single-phase the power falls to zero 3 times per cycle. Thus, in a 3 phase power supply, the power is being constantly delivered.

What are the benefits of running 3 Phase Power?

  • Instantaneous power
  • Transmission efficiency – minimum of 2% to 3% more power efficiency of 3 phase over single phase
  • More efficient use of conductors – 3 phase delivers three times the amount of power with three wires instead of two, doubling the usefulness. Over long distances, this is a significant cost saving
  • 3 phase motors run smoothly – power is delivered at a constant rate, with no torque variation or vibration. Reversing can be as simple as interchanging any two phases. The advantage of smoothness also applies to the 3 phase generators as they absorb power
  • 3 phase is easy to generate, easy to transmit, and easy to manipulate in many different ways – 3 phase delivers 1.7 times more amps per whip, reducing number of cables to run
  • 3 phase may be the only distribution option – at very high rack densities: 60 amps+/rack
  • electric motors will be more powerful if using 3 phase power – they will last longer, can be cheaper (no starter required)

What are the disadvantages of running 3 Phase Power?

  • Slightly more complex to design and wire – generally very thick electrical cables are used with 3 phase input cables
  • Must maintain a balanced power consumption across all wire pairs to maintain efficiency – this is mainly applicable to a 3 phase motor operation and less of a problem for a single phase load
  • More current means more risk – 10 kVA per circuit is common. A good idea is to use circuit breakers


Call Prolux Electrical Contractors on 1800 800 880
The Melbourne electrician for all of your power upgrades and 3 phase power electrical requirements.

3/52 Corporate Boulevard, Bayswater VIC 3153