Voltage rise calculator
Voltage rise calculator for solar and embedded generation in New Zealand and Australia, checked against the AS/NZS 4777.1 limit.
Inputs
Worked example with the default inputs. The live calculator replaces it when the page loads.
- Phases
- Single phase
- Voltage
- 230 V
- Inverter output
- 5 kW
- Power factor
- 1
- Run length
- 30 m
- Standard
- NZ · AS/NZS 3008.1.2
- Cable
- 10 mm² Copper PVC 75 °C
- Voltage rise limit
- 2 %
Voltage rise
1.26%
- Inverter current
- 21.74A
- Voltage rise
- 2.91V
- Maximum length at limit
- 47.44m
- Voltage rise limit
- 2%
This result is a design aid. Verify it against the current standard.
Calculation steps
- Inverter output current21.74A
- Resistance2.23Ω/kmAS/NZS 3008.1.2:2017 Table 30 (Xc), Tables 34–35 (Rc) p.98, p.102–103
- mV/A·m4.46mV/A·mAS/NZS 3008.1.2:2017 Cl 4.5
- Voltage rise2.91V
- Voltage rise percent1.26%
- Maximum length47.44m
Questions
Each answer describes what this tool calculates. The result is a design aid. Verify against the current standard.
What does the voltage rise calculator do?
The tool works out the inverter output current from its rating, the voltage and the power factor. It then works out the rise along the cable to your point of supply, in volts and as a percent. It also reports the longest run that still meets the limit.
What voltage rise limit does the tool use?
The tool uses 2 percent as the default and you can change it. AS/NZS 4777.1:2016 Clause 3.3.3 sets that limit at your point of supply, worked out at the inverter rated current. AS/NZS 3000:2018 Clause 3.6.2 Note 3 refers voltage rise to that Standard. Confirm the edition that applies.
Which inputs matter most?
The inverter rating and the run length scale the rise directly. The conductor size and material set the resistance. The power factor is limited to the range 0.8 to 1 and defaults to 1, which is the usual inverter case. Cables in parallel divide the impedance.
What else should I check?
This tool covers the rise on the inverter cable only. It does not cover the supply network, protection or anti islanding. Use the cable size tool to check the same cable's current rating. The inputs sit in the page address, so a link reproduces the calculation.
Worked examples
Background
Clauses and tables this tool reads
- AS/NZS 3008.1.2:2017 Cl 4.5Voltage drop method
- AS/NZS 4777.1:2016 Cl 3.3Inverter connection voltage rise
- AS/NZS 3008.1.2:2017 Table 30, 34, 35Reactance at 50 Hz and a.c. resistance at 50 Hz
- AS/NZS 3008.1.1:2017 Table 30, 34, 35Reactance at 50 Hz and a.c. resistance at 50 Hz
Every clause and table, with how each was verified
Tables last checked on 24 Sept 2026.