Use the Australian research to understand the question, then use measurements from your own site to assess the opportunity.
High voltage is a credible reason to investigate
The ESB-commissioned UNSW study examined 2018–19 Solar Analytics data: 12,617 predominantly residential PV sites, including 4,337 with a full year. It found generally elevated voltages, with substantial local variation. UNSW, May 2020, pp. 6–9.
What does “above nominal” mean? Australia’s nominal low-voltage reference is 230 V. The AER describes the allowable supply range as approximately 216–253 V. Being above 230 V can still be within that range. AER, April 2025, p. 3.
Five useful voltage checkpoints
235 V, 240 V and 245 V are screening checkpoints here. Only 230 V is the nominal reference. The report does not publish national location percentages for these checkpoints.
Requested thresholds: what can be stated about locations?
Voltage threshold How to use it at your site
> 230 V Nominal reference Compare sustained voltage during working hours with the requirements of your equipment.
> 235 V Screening checkpoint A modest elevation warrants checking the load mix and the practical reduction available.
> 240 V Screening checkpoint Assess how frequently this level coincides with material electricity consumption.
> 245 V Screening checkpoint Sustained readings at this level are a useful reason to investigate a voltage assessment.
> 253 V Upper supply-range reference Investigate recurring high voltage with the distributor and an electrical professional.
The study records five-minute maxima/minima from five-second samples; these are not statutory compliance measurements. A legal compliance conclusion needs the applicable jurisdictional rules and prescribed measurement method. Its sample is not a national census or a current estimate of commercial-site suitability. UNSW, pp. 46 and 117.
Why distinguish readings, time and locations?
“The percentage of readings above a threshold” and “the percentage of sites affected” answer different questions. One site can produce thousands of readings. A site can also have a high average while experiencing occasional low voltage.
For a useful assessment, ask for the percentage of valid operating time above each checkpoint, the time and load associated with those intervals, the minimum voltage by phase, and the proportion of the monitoring period with valid data.
Compare networks and local conditions
The following historical results describe sampled sites with five-minute maximum voltage above 253 V in at least 2% of recorded intervals. Values are approximate, from the report’s detailed Section 7. They are network sample results, not statewide population estimates or savings percentages.
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