Voltage rise calculator
Voltage rise calculator for solar and embedded generation in New Zealand and Australia, checked against the AS/NZS 4777.1 limit.
Reads AS/NZS 3008.1.2:2017 (NZ), AS/NZS 3008.1.1:2017 and 2025 (AU) and AS/NZS 4777.1:2016. Tables checked 27 Sept 2026.
Try a job 6
Each job fills in example values. Replace them with your values.
- Check solar voltage riseThe voltage rise on a 45 m cable from a 5 kW inverter.
- Check rise on a three-phase inverterThe rise on a 10 kW three-phase inverter cable of 30 m.
- Check rise on a long rural runThe rise on 5 kW over 80 m.
- Check rise against a 2 % limitThe rise on a 3 kW inverter in Australia against 2 %.
- Check rise on a battery inverterThe rise on a 5 kW battery inverter over 15 m.
- Check rise on a 30 kW arrayThe rise on a 30 kW commercial inverter over 40 m.
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/km
AS/NZS 3008.1.2:2017 Table 30 (Xc), Tables 34–35 (Rc) p.98, p.102–103
- mV/A·m4.46mV/A·m
AS/NZS 3008.1.2:2017 Cl 4.5
- Voltage rise2.91V
- Voltage rise percentResult1.26%
- Maximum length47.44m
About this calculator
How this is calculated
The tool works out the voltage rise on the cable between an inverter and its point of supply. It uses the cable data of AS/NZS 3008.1.2:2017. The Australian choice reads AS/NZS 3008.1.1:2025 and the superseded 2017 edition.
- Inverter current. The tool divides the inverter power by the voltage and the power factor. On three phases, it also divides by the square root of three.
- Resistance and reactance. It reads the conductor resistance from Tables 34 and 35. It reads the reactance from Table 30. It uses the value for your size, material and insulation.
- Millivolts per ampere metre. It combines both values with the power factor. This is the method of Cl 4.5.
- Voltage rise. It multiplies the millivolts per ampere metre by the current and the run length. It gives the result in volts and as a percentage of the supply voltage.
- Maximum length. It finds the run length at which the rise equals your limit.
The limit is an input. AS/NZS 3000:2018 Cl 3.6.2 Note 3 refers the rise limit to AS/NZS 4777.1. Check the current edition for the value that applies to your site.
Worked example
- 5 kW inverter on 30 m of 10 mm² copper. The supply is single-phase at 230 V with a power factor of 1. The inverter current is 21.74 A. The voltage rise is 2.91 V, or 1.26 %. That is within a limit of 2 %. The longest run at that limit is 47.44 m.
Limits
The limit of 2 % is a default you can change. It is not a value read from a standard. The tool does not check the inverter voltage settings or the rules of the network operator.
The reactance is the Table 30 value for a multicore cable. A single-core run reads a higher reactance for its formation. The tool does not size the cable for current. Use the cable size calculator for that.
See also: Solar inverter voltage rise at 5 kW, Voltage rise on a long rural PV run and the PV string tool.
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
- AS/NZS 3008.1.1:2025 Table 4.1(A), 4.1(B), 4.5(A), 4.5(B)Reactance at 50 Hz and a.c. resistance at 50 Hz
Every clause and table, with how each was verified
Tables last checked on 27 Sept 2026.
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