Did AS/NZS 4777.1:2024 change the 2% voltage rise limit?

No. Standards Australia published AS/NZS 4777.1:2024 in August 2024, superseding the 2016 edition, but the voltage rise requirement carries over unchanged: Clause 3.3.3 still caps the overall rise from the point of supply to the inverter a.c. terminals at 2% of the nominal voltage at the point of supply, assessed at the rated current of the inverter energy system. The clause number, the 2% figure and the 4.6 V single-phase / 8 V three-phase line-to-line equivalents are all the same. This calculator applies the 2024 edition. Check your DNSP connection rules as well, because several networks impose a tighter limit (commonly 1%) than the Standard.

What is the AS/NZS 4777.1 voltage rise limit for solar inverters in Australia?

AS/NZS 4777.1:2024 Clause 3.3.3 requires that the voltage rise from the point of supply to the inverter a.c. terminals (the grid-interactive port) does not exceed 2% of the nominal voltage at the point of supply, calculated using the rated current of the IES. For 230 V single-phase that is 4.6 V; for 400 V three-phase that is 8 V line-to-line (or 4.6 V line-to-neutral). The limit applies to the entire inverter path (inverter cable plus any final subcircuit, submain and consumer mains in series back to the point of supply) not to each segment separately, and it applies in addition to the AS/NZS 3000 voltage drop requirements.

How is voltage rise calculated for a grid-connected solar PV inverter?

Per AC cable segment ΔU = K × I × (R·cosφ + X·sinφ) × L, where K = 2 for single-phase (active plus neutral return) and K = √3 for balanced three-phase, I is the rated current of the IES in amperes (AS/NZS 4777.1 Clause 3.3.3 specifies the rated current of the IES, not a reduced figure), R and X are the conductor resistance and reactance per metre from the AS/NZS 3008.1.1:2025 impedance tables at the insulation operating temperature, L is the cable route length in metres, and φ is the inverter operating power factor angle. At worst case the bracket is replaced by the impedance magnitude √(R² + X²). The segment rises are summed across every cable from the inverter to the point of supply, divided by nominal voltage, and compared against the 2% AS/NZS 4777.1 limit.

Does the 2% AS/NZS 4777.1 voltage rise limit include the consumer mains?

Yes. AS/NZS 4777.1 Clause 3.3.3 measures the rise from the point of supply to the inverter a.c. terminals: the network connection point at the consumer mains origin. The consumer mains, submain, final subcircuit and inverter AC cable are all in that path, so their voltage rise contributions add together. Once you set the inverter connection point, the calculator includes every segment in the path automatically.

How do I reduce voltage rise on a solar PV installation that fails the 2% limit?

Work the mitigation hierarchy from cheapest first: (1) shorten the AC cable run; (2) increase the cable cross-sectional area on the segment with the largest absolute rise. Doubling CSA roughly halves rise on that segment; (3) switch from single-phase to three-phase inverters where supply allows (cuts current by ~3×); (4) move the inverter connection upstream (e.g. MSB instead of final board); (5) choose copper over aluminium for the inverter cable; (6) cluster smaller inverters across different boards; (7) request a DNSP tap change or feeder upgrade as a last resort.

Does an export-limited inverter still have to satisfy the 2% voltage rise limit?

Yes: the 2% limit always applies. By default AS/NZS 4777.1 Clause 3.3.3 says the rise is calculated from the rated current of the IES, not a reduced export figure, so an export-limited inverter is still assessed at its rated current unless the network agreement says otherwise. The standard's one allowance is for an aggregate IES rating above 30 kVA, where the site's known minimum load may be taken into account. Where your DNSP accepts a compliant AS/NZS 4777.2 hard export limit for the rise calculation, the calculator's Export Limit toggle applies the limited kW to the consumer mains only: the one segment beyond the export-limit measurement point, with the submains and each inverter cable still assessed at full output; otherwise size on the full IES rated current.

How does the calculator handle multiple inverters on the same installation?

Add each inverter with its own size, name and AC cable run; the connection point (MSB direct or via a DB) is set once for the installation and is shared by every inverter. The tool aggregates currents per segment: the consumer mains and, where used, the submain carry the sum of all inverters, while each inverter's own final subcircuit carries only its own current. The final pass/fail verdict checks the worst-case inverter path against the 2% AS/NZS 4777.1 limit.

What is the difference between voltage drop and voltage rise?

Voltage drop occurs on cables supplying loads (current flows consumer-mains to load) and is governed by AS/NZS 3000:2018 Cl. 3.6.2, which sets a 5% limit from the point of supply to any point in the installation (a note to that clause allows more where supply comes from a substation forming part of the installation). Voltage rise occurs on cables exporting from generation (current flows inverter to point of supply) and is governed by AS/NZS 4777.1:2024 Cl. 3.3.3 with a 2% inverter-path limit. The same cable on the same install has both (drop under maximum demand and rise under maximum export), but they are assessed separately: this calculator covers the AS/NZS 4777.1 inverter-path voltage rise, while the ElecAS Voltage Drop calculator covers the load-side drop.

Should I use worst-case power factor for AS/NZS 4777.1 voltage rise?

Yes, wherever the inverter is configured for any AS/NZS 4777.2 reactive response mode (volt-var, fixed PF other than unity, PF response), because the operating PF then moves with terminal voltage and is not a fixed number you can enter. Worst Case mode uses the impedance magnitude Z = √(R² + X²), which is the maximum value R·cosφ + X·sinφ can take at any power factor, so the reported rise bounds every PF the inverter could be commanded to. Turn it off and enter a power factor only when the inverter is locked to a known fixed PF by the DNSP connection agreement.

Does AS/NZS 4777.1 require a combined voltage drop and voltage rise check?

Not as a single combined calculation. AS/NZS 4777.1 Clause 3.3.3 states that its 2% voltage rise requirement applies in addition to the voltage drop requirements of AS/NZS 3000, so the two are assessed separately and both must be satisfied: the AS/NZS 3000 load-side drop (up to 5%) under maximum demand, and the 2% inverter-path rise under maximum generation. The underlying aim is to keep the consumer's utilisation voltage inside the AS 60038 range, with the point of supply held at or below 253 V (230 V +10%). This calculator covers the AS/NZS 4777.1 inverter-path voltage rise only; for the load-side drop and maximum demand use the ElecAS Voltage Drop and Maximum Demand calculators.

What cable size do I need for a 5 kW single-phase solar inverter to satisfy the 2% voltage rise limit?

A 5 kW single-phase inverter exports about 21.7 A continuous at 230 V, and the 2% limit gives it a 4.6 V budget for the whole path. For copper multicore cable with 90 °C insulation (V-90 or X-90) at worst-case impedance, 4 mm² covers roughly 17 m of total path, 6 mm² about 26 m, 10 mm² about 45 m and 16 mm² about 71 m. In 75 °C V-75 the same sizes reach about 18 m, 28 m, 47 m and 75 m. Those lengths are the whole run added together (inverter cable plus any submain plus the consumer mains), not per segment. The ElecAS calculator returns the actual smallest standard size after applying the AS/NZS 3008.1.1:2025 impedance values and the AS/NZS 4777.1 2% limit to your specific install.

Does cable temperature affect voltage rise?

Yes. AS/NZS 3008.1.1:2025 publishes its conductor impedance tables (Tables 4.1 to 4.10) at the maximum continuous operating temperature of each insulation class: 75 °C for V-75 PVC, 90 °C for V-90 PVC, X-90 XLPE and R-90 elastomer, and 110 °C for X-110 XLPE and R-110 elastomer. Resistance rises ~0.4% per °C in copper, so an XLPE inverter cable at 90 °C exhibits a few percent more rise than the same conductor sized in V-75 PVC. The ElecAS calculator selects the correct temperature row automatically based on the chosen insulation.

What size AC cable do I need for a 6.6 kW solar system?

First check what the 6.6 kW refers to. On most Australian residential systems it is the panel array, paired with a 5 kW inverter, and AS/NZS 4777.1 Clause 3.3.3 assesses voltage rise at the rated current of the inverter energy system: so that system is sized on the 5 kW inverter, about 21.7 A, and 6 mm² copper covers roughly 26 m of total path with 10 mm² reaching about 45 m. Where the inverter itself is rated 6.6 kW it draws about 28.7 A, and the same cables cover about 20 m and 34 m. Those lengths are the whole path added together (the inverter cable plus any submain plus the consumer mains), for copper multicore cable with 90 °C insulation at worst-case impedance. Enter your actual segments in the calculator for the size that applies to your run.

Why does my solar inverter keep tripping or shutting down on sunny days?

The usual cause is high terminal voltage, and cable voltage rise is the part of it a designer controls. The inverter sees the network voltage at the point of supply plus the rise its own cable adds. On a clear afternoon the local feeder is already near the top of the AS 60038 range because every system in the street is exporting, so a cable adding several volts of its own can push the inverter past its AS/NZS 4777.2 limits. Before it disconnects it will usually curtail first (volt-watt response), which shows up as a flat top on the output curve rather than an alarm. Run the installation through this calculator: if the total rise is at or near 2% the a.c. cable is a genuine contributor, and going up one size on the segment with the largest absolute rise is normally the cheapest fix. If the rise is well under 2%, the problem is upstream network voltage and the DNSP needs to be involved.

Do battery, hybrid and multi-mode inverters have to meet the 2% voltage rise limit?

Yes. AS/NZS 4777.1 applies to the grid connection of energy systems via inverters generally, not to solar PV specifically, so a battery inverter, a hybrid PV and battery inverter or a multi-mode inverter is assessed the same way: 2% of nominal from the point of supply to the inverter a.c. terminals, at the rated current of the inverter energy system. What changes is the current. A battery inverter is often rated for a higher continuous a.c. discharge than the PV inverter beside it, and it can hold that output at any time of day rather than only around solar noon, so it is not safe to assume the PV case is the worst one. Enter each inverter in the calculator with its own a.c. rating and cable run and the shared segments are aggregated automatically.

My DNSP requires 1% voltage rise instead of 2%. Can I calculate that?

Yes. Switch the calculator to Advanced and enter the network's figure in the Max Rise field. Everything downstream follows it: the pass/fail verdict, the per-segment breakdown, the suggested minimum cable sizes and the exported PDF all run against the limit you set rather than the 2% default. Several Australian networks apply a tighter allowance than AS/NZS 4777.1 through their connection agreement or service and installation rules, usually on feeders already known to run high, and the tighter figure governs where it applies. On a 230 V single-phase supply a 1% limit is 2.3 V for the whole path, which roughly halves every maximum length in the tables on this page.

What is the maximum AC cable length for a solar inverter?

There is no single figure: the limit is a voltage budget, not a distance, so the answer depends on the inverter current and the conductor. AS/NZS 4777.1 gives the whole path 2% of nominal, which is about 4.6 V on 230 V single-phase. For copper multicore cable with 90 °C insulation at worst-case impedance, a 5 kW single-phase inverter reaches about 17 m on 4 mm², 26 m on 6 mm², 45 m on 10 mm² and 71 m on 16 mm². A 10 kW three-phase inverter on the same sizes reaches about 54 m, 81 m, 137 m and 217 m, because three-phase carries roughly a third of the current for the same kW. Those numbers are the total of every cable between the inverter and the point of supply, so the consumer mains and any submain come out of the same budget before the inverter cable gets what is left.

Do I calculate voltage rise from the panel kW or the inverter kW?

The inverter. AS/NZS 4777.1 Clause 3.3.3 assesses the rise at the rated current of the inverter energy system, and the a.c. cable only ever carries what the inverter puts out. An oversized array (a "6.6 kW system" on a 5 kW inverter is the standard Australian example, and CEC rules allow the array to exceed inverter rating by up to a third) does not increase the a.c. current: it makes the inverter hold its rated output for more hours of the day. So enter the inverter's continuous a.c. rating in kW, and where several inverters share a board, enter each of them so the shared submain and consumer mains are assessed on the aggregate.

Does the AS/NZS 4777.1 voltage rise limit apply in New Zealand?

Yes. AS/NZS 4777.1 is a joint Australian and New Zealand standard, and the Clause 3.3.3 2% inverter-path limit reads the same on both sides of the Tasman. New Zealand also shares the AS 60038 nominal voltages (230 V single-phase, 400 V three-phase) and uses AS/NZS 3008.1.1 for conductor impedance, so this calculator applies unchanged. What differs is the connection process: the local lines company sets its own distributed generation application requirements, and may apply a tighter voltage rise allowance than the standard, which you can enter in the Max Rise field in Advanced mode.

Can I use aluminium cable for solar inverter AC connections?

Yes: aluminium is permitted under AS/NZS 3000 for solar inverter AC cables, particularly on larger commercial systems where the mains and submain are already aluminium. Aluminium has roughly 1.6× the resistance of copper for the same cross-section, so it contributes more voltage rise per metre, and the calculator restricts it to the 75 °C and 90 °C insulation classes (V-75, X-90, R-90) because 110 °C aluminium is not manufactured in Australia. Aluminium sizes also start at 16 mm². Always confirm aluminium-rated terminations on the inverter, isolator and switchboard: many smaller residential inverters specify copper-only terminations.

ElecAS

Voltage Rise Calculator: AS/NZS 4777.1 Solar PV & Inverter Compliance for Australia

Free, browser-based AS/NZS 4777.1 voltage rise calculator built for Australian solar PV designers, CEC accredited installers, electricians and electrical engineers. Models the full inverter-to-point-of-supply path (consumer mains, submains and each inverter's own final subcircuit) and applies the AS/NZS 4777.1 Clause 3.3.3 limit that the voltage rise from the point of supply to the inverter a.c. terminals must not exceed 2% of nominal voltage, calculated at the rated current of the IES (4.6 V on a 230 V single-phase system, 8 V line-to-line on a 400 V three-phase system). Supports single-phase and three-phase installations, multiple inverters sharing the mains and submains with an independent cable run per inverter, worst-case impedance evaluation, export-limited systems, copper and aluminium conductors, 75 °C PVC (V-75), 90 °C XLPE (X-90) and elastomeric (R-90) and 110 °C XLPE and elastomeric (X-HF-110, R-HF-110) insulation, multi-core and single-core arrangements, and the 1–630 mm² cable size range wherever AS/NZS 3008.1.1 publishes an impedance row for the chosen arrangement. Returns a per-segment voltage rise breakdown, total rise in volts and percent, a pass/fail pill against the 2% AS/NZS 4777.1 envelope, automatic suggestion of compliant cable sizes when a segment fails, and a branded PDF voltage rise compliance report ready for the DNSP / network operator submission.

Solar inverter voltage rise, calculated to AS/NZS 4777.1

Check solar inverter voltage rise against the AS/NZS 4777.1 2% limit. Enter the inverters, the cables and the run lengths, and this voltage rise calculator works the whole path from the inverter a.c. terminals back to the point of supply using AS/NZS 3008.1.1:2025 impedances, then tells you whether it passes and which cable to upsize if it does not.

Voltage rise at a glance: the AS/NZS 4777.1 2% limit

AS/NZS 4777.1 Clause 3.3.3 caps voltage rise at 2% of nominal from the point of supply to the inverter a.c. terminals.
AS/NZS 4777.1:2024 superseded the 2016 edition in August 2024 and kept Clause 3.3.3 and the 2% limit unchanged. This calculator applies the 2024 edition.
The 2% limit is about 4.6 V on a 230 V single-phase supply and 8 V line-to-line on 400 V three-phase.
The 2% is the budget for every cable in the path added together, not a limit for each cable on its own.
Voltage rise is evaluated at the rated current of the inverter energy system at full export.
Rise is the mirror image of voltage drop and uses the same AS/NZS 3008.1.1 conductor impedances.
A 6.6 kW single-phase inverter draws about 28.7 A, which gives 6 mm² copper roughly 20 m of total path and 10 mm² about 34 m.
Three-phase cuts the current for the same kW by about three, so the same cable carries a much longer run: a 13.2 kW three-phase system reaches about 61 m on 6 mm².
The 2% rise limit is separate from, and additional to, the AS/NZS 3000 Clause 3.6.2 voltage drop limit. Both have to be satisfied.

Who this voltage rise calculator is for

CEC accredited solar designers and installers, electrical contractors, distributed generation engineers and DNSP connection specialists checking the inverter-path voltage rise on residential, commercial and industrial solar PV and battery storage installations across Australia and New Zealand.

Standards this voltage rise calculator applies

AS/NZS 4777.1:2024 (Grid Connection of Energy Systems via Inverters: Installation Requirements, including Clause 3.3.3 voltage rise)
AS/NZS 4777.2:2020 (Grid Connection of Energy Systems via Inverters: Inverter Requirements)
AS/NZS 3000:2018 (Wiring Rules: Clause 3.6 voltage drop budget, Clause 7.3 alternative supply systems)
AS/NZS 3008.1.1:2025 (Cable Selection: Tables 4.1–4.10 conductor R and X impedance values)
AS/NZS 5033:2021 (Installation and Safety Requirements of Photovoltaic (PV) Arrays)
AS 60038 (Standard Voltages: 230 V / 400 V nominal voltage used to express the rise as a percentage)
AS/NZS 4509 (Stand-Alone Power Systems, where applicable)

What this voltage rise calculator does

Applies the AS/NZS 4777.1:2024 Clause 3.3.3 inverter-path voltage rise limit: 2% of nominal voltage from the point of supply to the inverter a.c. terminals, calculated at the rated current of the IES and evaluated across every cable segment in the path.
Models the complete path the inverter sees back to the network (consumer mains, submains and each inverter's final subcircuit), with the connection point set either to MSB direct (POS → MSB → inverter) or via a distribution board (POS → MSB → DB → inverter), which fixes exactly which cable segments carry the export current.
Supports multiple inverters per project (each with its own size, name and dedicated AC cable run) with results aggregated to a single compliance verdict so multi-inverter and string-inverter installations are sized correctly first time.
Single-phase (230 V) and three-phase (400 V) systems, with the calculator switching between line-to-neutral and line-to-line voltage rise automatically and supporting worst-case power factor evaluation for inverters operating at unity, leading or lagging PF.
Copper (standard and flexible) and aluminium conductors, 75 °C PVC (V-75), 90 °C XLPE (X-90) and elastomeric (R-90), and 110 °C XLPE and elastomeric (X-HF-110, R-HF-110) insulation, across the 1 mm² to 630 mm² size range: the size list is filtered to the sizes AS/NZS 3008.1.1:2025 actually publishes for the chosen conductor and arrangement, so a size with no impedance row is never offered.
Cable arrangement selector (multicore circular, multicore shaped, and single-core in trefoil, flat touching or spaced formation) chooses the AS/NZS 3008.1.1 impedance row that matches the real install, so the reactance used in the rise reflects how the cores are actually run.
Auto-size assistant flags a failing segment and suggests the smallest standard cable size that brings the inverter-path rise back under the 2% AS/NZS 4777.1 limit, so over-sizing is only proposed where the compliance check requires it.
Export-limit aware: when a hard export limit is configured the calculator applies the limited current to the consumer mains (the only segment beyond the export-limit measurement point), avoiding the false fail that comes from using nameplate output on export-limited systems.
Branded PDF voltage rise compliance report with full project metadata (project name, number, address, designer, revision, date), single-line schematic of the inverter path, per-segment results and a pass/fail summary: ready for the DNSP / network connection application.
Built and reviewed by a Chartered Professional Engineer (CPEng, NER, NSW DBP, NSW PRE, APEC, IntPE Aus): see the Verification page for the testing and review process.

How to calculate solar inverter voltage rise, step by step

Enter inverter sizes and number of inverters: Add each inverter with its continuous AC output in kilowatts. For string solar add one inverter per string; for multi-inverter systems add all inverters that share the same connection point so the calculator aggregates their current correctly.
Select phases and nominal system voltage: Set Phases to 1 (230 V single-phase) or 3 (400 V three-phase line-to-line / 230 V line-to-neutral). The calculator uses the AS 60038 nominal voltage to convert the per-segment rise into a percentage.
Set the connection point: Choose MSB direct, where the inverters connect at the main switchboard and the path is POS → MSB → inverter, or Via DB, where they connect at a downstream distribution board and the path is POS → MSB → DB → inverter. This fixes the sequence of cable segments the inverter current flows through back to the point of supply.
Enter each cable segment: For the consumer mains, the submains (when connecting via a DB) and each inverter's final subcircuit, enter cable size (mm²), conductor (copper, flexible copper or aluminium), insulation (V-75, X-90, R-90, X-110 or R-110) and length in metres. The calculator pulls R and X per kilometre from the AS/NZS 3008.1.1:2025 impedance tables at the insulation operating temperature.
Pick the cable arrangement: Select the arrangement that matches the physical install: multicore circular, multicore shaped, or single-core in trefoil, flat touching or spaced formation. The arrangement controls which impedance row the tool reads, and therefore the reactance used in the rise.
Set power factor and worst-case mode: Leave Worst Case on so the tool uses the full impedance magnitude Z = √(R² + X²): the largest value R·cosφ + X·sinφ can take at any power factor. Untick it and enter a power factor only when the inverter is configured to operate at a known fixed PF.
Apply export limit if configured: If the inverter has a hard export limit set by the DNSP connection agreement, switch on Export Limit and enter the limit in kW. The calculator applies the limited current to the consumer mains (not nameplate), so the rise on the shared upstream cable reflects the real continuous export.
Review the pass/fail and per-segment breakdown: Each segment shows its own voltage rise contribution and the total rise from the inverter terminals to the point of supply is compared against the 2% AS/NZS 4777.1 envelope. Where a segment fails the auto-size assistant suggests the smallest compliant cable size.
Export the branded PDF compliance report: Fill in the project metadata (project name, number, address, designer, revision, date) and export the voltage rise compliance report. Submit it with the DNSP / network connection application alongside the SLD and protection settings.

AS/NZS 4777.1 voltage rise for solar PV: practical engineering guide

What voltage rise is and why AS/NZS 4777.1 limits it

When a grid-connected inverter exports active power, current flows back through the inverter AC cable, the final subcircuit, the submain and the consumer mains toward the point of supply. The IR + IX impedance of every conductor between the inverter and the network lifts the inverter terminal voltage above the nominal supply voltage. The rise is exactly the mirror image of voltage drop: same impedance values, same length, but in the opposite direction.

AS/NZS 4777.1:2024 Clause 3.3.3 limits the rise from the point of supply to the inverter a.c. terminals to 2% of nominal voltage, calculated at the rated current of the IES. On a 230 V single-phase system the limit is 4.6 V; on a 400 V three-phase system the line-to-line limit is 8 V (or 4.6 V line-to-neutral). The reason the limit is tight is that the inverter monitors voltage at its own terminals: as the rise approaches the AS/NZS 4777.2 over-voltage trip point (255 V default on 230 V), the inverter starts curtailing output (volt-watt response), and a few volts of cable rise turns into kilowatt-hours of lost generation across a year.

What the 2% voltage rise limit means in volts

The 2% is a percentage of the nominal voltage at the point of supply, so it converts to a fixed number of volts before you calculate anything. On a 230 V single-phase supply, 2% is 4.6 V. On a 400 V three-phase supply, 2% is 8 V line-to-line, which is the same 4.6 V measured line-to-neutral. That figure is the entire budget for every cable between the inverter a.c. terminals and the point of supply added together, not per cable.

What that budget buys in metres depends on the current and the conductor. The table below is the maximum total inverter-path length that stays inside the 2% limit, taken straight from the same AS/NZS 3008.1.1:2025 impedance tables and worst-case impedance the calculator uses, for copper multicore cable with 90 °C insulation (V-90 or X-90, the usual solar a.c. cable). Cable in 75 °C V-75 runs a little cooler and buys roughly 5% more length. Treat these as a sizing sanity check, not a substitute for running the real path: a real installation splits the budget across the inverter cable, any submain and the consumer mains.

Maximum total inverter-path length at the AS/NZS 4777.1 2% voltage rise limit (copper, multicore, 90 °C insulation, worst-case impedance)
Cable size	5 kW single-phase (21.7 A)	10 kW single-phase (43.5 A)	10 kW three-phase (14.4 A)	30 kW three-phase (43.3 A)
4 mm²	17 m	8 m	54 m	18 m
6 mm²	26 m	13 m	81 m	27 m
10 mm²	45 m	22 m	137 m	45 m
16 mm²	71 m	35 m	217 m	72 m
25 mm²	113 m	56 m	343 m	114 m
35 mm²	157 m	78 m	475 m	158 m

Cable size by inverter rating: the sizes Australian systems actually use

The table above is keyed to round numbers. This one is keyed to the inverter ratings that turn up on real Australian jobs, and it answers the question people actually type: what size a.c. cable does this system need. Read it against the inverter's a.c. rating, not the panel array. A "6.6 kW system" is usually 6.6 kW of panels on a 5 kW inverter, and AS/NZS 4777.1 Clause 3.3.3 assesses the rise at the rated current of the inverter energy system, so that system is a 5 kW case. Use the 6.6 kW column only where the inverter itself is rated 6.6 kW.

These lengths are the whole inverter path added together, produced by this calculator at worst-case impedance on copper multicore cable with 90 °C insulation (V-90 or X-90, the usual solar a.c. cable). A real design splits that budget across segments: take off the consumer mains and any submain first, and what is left is what the inverter cable can be. Cable in 75 °C V-75 runs cooler and buys roughly 5% more length.

Maximum total inverter-path length at the AS/NZS 4777.1 2% limit, by inverter a.c. rating (copper, multicore, 90 °C insulation, worst-case impedance)
Cable size	6.6 kW single-phase (28.7 A)	10 kW single-phase (43.5 A)	13.2 kW three-phase (19.1 A)	20 kW three-phase (28.9 A)
4 mm²	13 m	8 m	41 m	27 m
6 mm²	20 m	13 m	61 m	40 m
10 mm²	34 m	22 m	103 m	68 m
16 mm²	54 m	35 m	164 m	108 m
25 mm²	86 m	56 m	260 m	171 m
35 mm²	118 m	78 m	359 m	237 m

Why voltage rise costs generation: curtailment before tripping

The 2% limit is not paperwork. An inverter measures voltage at its own terminals, and what it sees is the network voltage at the point of supply plus every volt the cable adds on the way back. Australian low-voltage feeders already sit near the top of the AS 60038 band on clear afternoons, when every inverter in the street is exporting and lifting the local voltage together. A cable contributing 4 V of its own is what turns a supply sitting at 250 V into an inverter reading 254 V.

What happens next is gradual, which is why it goes unnoticed. Under AS/NZS 4777.2:2020 the inverter first backs off active power as terminal voltage climbs (volt-watt response), and only disconnects if the voltage keeps going. Nobody gets an alarm for the first part. What the customer sees is a system generating less than it should between late morning and mid afternoon on the sunniest days, and a monitoring app whose output curve has a flat top. Of everything contributing to that terminal voltage, the cable is the part a designer controls.

This is also why a design that just scrapes under 2% is worth a second look. The limit is a compliance ceiling, not a design target. On a feeder that already runs high, halving the cable rise by going up one size is often the difference between a system that curtails on its best generating days and one that does not, and the extra copper is paid back over the life of the system. The per-segment breakdown in this calculator is there to show which cable is worth the upgrade: it is almost never all of them.

What the network operator asks for, and what to send

Most Australian DNSPs require a voltage rise calculation as part of the grid connection application, and a bare pass or fail with no working behind it is increasingly sent back. What the network is checking is that the inverter will hold its output on a feeder they already know runs high, so a useful submission shows the path, the cable in each segment, the current used and the rise each segment contributes, not just a total.

Some networks apply a tighter figure than the standard does. Where a connection agreement or a network service and installation rule sets 1% rather than the AS/NZS 4777.1 2%, switch this calculator to Advanced and enter that figure in Max Rise: the whole check then runs against it, including the pass/fail, the per-segment breakdown, the cable-size suggestion and the exported report. Where the network sets a hard export limit and accepts sizing against it, the Export Limit toggle applies the capped current to the consumer mains, which is the one segment beyond the export-limit measurement point.

The exported PDF is built for that submission: project name, number, address, designer, revision and date, a single-line schematic of the inverter path, the per-segment rise in volts and percent, the standards applied, the power factor basis used, and the pass/fail against the limit that was actually set. It is the calculation shown as working, which is what a network reviewer is asking to see.

The 2% inverter path: what the limit actually covers

The 2% limit applies to the entire inverter path from the inverter AC terminals back to the point of supply (the network connection point: typically the consumer mains origin / network meter). It is not a per-segment limit. The calculator therefore sums the rise on every cable in the path (inverter cable, final subcircuit (where the inverter does not connect directly at a board), submain and consumer mains), and compares the total against the 2% envelope.

The connection point selector in the tool fixes which segments are in the path. On MSB direct the path is the consumer mains plus each inverter's own final subcircuit back to the main switchboard. Via DB adds the submain between the MSB and the distribution board, so the path becomes mains plus submain plus each inverter's final subcircuit. The current in each segment is the inverter export current at that point: each inverter's own final subcircuit carries only its own current, while the shared submain and consumer mains carry the aggregated current of every inverter.

Single-phase vs three-phase behaviour

Both cases use the AS/NZS 3008.1.1 route form ΔU = K × I × Z × L, where K accounts for the return path, I is the rated current of the IES in amperes (per Clause 3.3.3), Z is the effective impedance per metre and L is the route length in metres. For a single-phase inverter K = 2 (active plus neutral), so ΔU = 2 × I × (R·cosφ + X·sinφ) × L, where R and X are the AS/NZS 3008.1.1 resistance and reactance and φ is the operating power factor angle. The result is a per-segment rise in volts line-to-neutral, divided by 230 V to express it as a percentage.

For a three-phase inverter K = √3, so the rise is √3 × I × (R·cosφ + X·sinφ) × L (line-to-line) for balanced three-phase output, with the percentage taken against 400 V. Three-phase inverters produce roughly one-third the per-phase current of a single-phase inverter of the same kW rating, so on the same cable run the rise in volts is around 30% of the single-phase figure and (because it is expressed against 400 V rather than 230 V) the percentage rise is closer to one-sixth. That is why moving from single-phase to three-phase is often the single most effective mitigation for marginal sites.

Worst-case power factor and AS/NZS 4777.2 volt-var

AS/NZS 4777.2:2020 requires inverters to provide reactive power response: volt-var, volt-watt, fixed PF and PF response modes. In an Australia A region default volt-var the inverter absorbs reactive power as terminal voltage rises (lagging from the grid’s perspective) and exports reactive when voltage falls. At the AS/NZS 4777.2 Australia A default, the inverter can be commanded to operate between roughly 0.8 leading and 0.8 lagging PF.

Because the inverter's operating PF moves with terminal voltage, the calculator's Worst Case mode does not pick a single PF. It uses the full impedance magnitude Z = √(R² + X²), which is mathematically the largest value R·cosφ + X·sinφ can take at any power factor: so the reported rise bounds every PF the inverter could be commanded to. Turning Worst Case off lets you enter a fixed power factor and evaluates Z = R·cosφ + X·sinφ at that PF, which is appropriate only when the inverter is locked to a known PF by the connection agreement.

Mitigation hierarchy: cheapest fix first

When a segment fails the 2% limit, work the mitigation ladder from cheapest to most disruptive. First, shorten the cable run: many failing installations are caused by an inverter mounted on the far side of the roof from the switchboard with an unnecessarily long AC cable. Second, increase the conductor cross-sectional area on the segment that contributes the largest absolute rise (the calculator’s per-segment table makes this obvious). Doubling the CSA roughly halves the rise on that segment.

Third, switch from single-phase to three-phase where the supply allows: the same kW rating produces a third of the current, and the rise drops by a factor of three. Fourth, move the connection point upstream: reconnecting the inverters at the main switchboard instead of a downstream distribution board (MSB direct rather than Via DB) removes the submain from the path entirely. Fifth, choose copper over aluminium for the inverter AC cable: copper has ~38% lower resistance per mm² so the rise on the inverter cable comes down by about a third for the same nominal size.

Sixth, consider inverter clustering: running two smaller three-phase inverters at different boards instead of one large single-phase inverter at the final board halves the per-segment current. Seventh, request a network upgrade or tap change at the distribution transformer: only used when every other mitigation has been exhausted, because the DNSP timeline is months and the cost is borne by the customer.

Export-limited systems and aggregated inverter current

Many Australian DNSPs cap residential and small commercial export to 5 kW single-phase or 15 kW three-phase. By default AS/NZS 4777.1 Clause 3.3.3 requires the voltage rise to be calculated from the rated current of the IES, not a reduced export figure: the standard’s only relief is the note allowing the site’s known minimum load to be taken into account for an aggregate IES rating above 30 kVA. Where the DNSP connection agreement accepts sizing on a compliant AS/NZS 4777.2 hard export limit, the calculator’s Export Limit toggle applies the limited kW to the consumer mains (the segment beyond the export-limit measurement point), while the submain and each inverter's own cable stay on full rated current; otherwise leave it off and size everything on the full IES rated current.

For multi-inverter installations the rise on each shared segment uses the sum of the currents of every inverter. Two 5 kW single-phase inverters on the same distribution board both contribute their 21.7 A to the submain and the consumer mains, but each carries only its own 21.7 A on its own final subcircuit. The tool aggregates the shared segments automatically and reports the pass/fail against the worst inverter path.

Standards reference set and how the tool uses them

AS/NZS 4777.1:2024 sets the inverter-path 2% rule (Cl. 3.3.3) and the installation requirements for grid-connected energy systems. AS/NZS 4777.2:2020 sets the inverter behaviour: over/under voltage trip points, volt-watt and volt-var response curves, anti-islanding and the rated output current that feeds the rise calculation.

Conductor impedance comes from the AS/NZS 3008.1.1:2025 impedance tables (Tables 4.1 to 4.10), with the row chosen by conductor material, insulation operating temperature, construction (multi-core or single-core) and installation method. AS/NZS 3000:2018 Cl. 3.6 sets the separate load-side voltage drop budget (5% from the network, 7% from an on-site substation): a parallel check handled by the ElecAS Voltage Drop calculator, not this inverter-path tool. AS 60038 fixes the nominal voltage (230 V single-phase, 400 V three-phase) used to express the rise as a percentage. AS/NZS 5033:2021 governs the DC array side and intersects with the AC side at the inverter.

Voltage rise terminology

Voltage rise: The increase in voltage at the inverter terminals above the point-of-supply voltage when the inverter exports power, caused by current flowing back through the cable impedance.
Point of supply: The boundary between the distribution network and the installation, from which the AS/NZS 4777.1 voltage rise path to the inverter terminals is measured.
Inverter energy system (IES): The AS/NZS 4777.1 term for the complete generating system connected through an inverter: the inverter or inverters, their controls and any battery or PV array behind them. Clause 3.3.3 assesses the rise at the rated current of the IES.
Rated current of the IES: The continuous a.c. output current the inverter energy system is rated for. It is the current the 2% check is calculated at, which is why a system is assessed at full output rather than at an average or expected export figure.
Export limit: A hard cap on the power an inverter system may export to the grid. It reduces the current, and therefore the voltage rise, in the shared consumer mains.
253 V ceiling: The +10% steady-state upper limit on a 230 V supply. Grid voltage near this ceiling plus cable voltage rise pushes the inverter toward its AS/NZS 4777.2 over-voltage response.
Volt-watt response: The AS/NZS 4777.2 mode that reduces an inverter's active power output as its terminal voltage climbs. It is why cable voltage rise costs generation: the inverter throttles itself before it trips.
Volt-var response: The AS/NZS 4777.2 mode in which the inverter absorbs or exports reactive power in response to terminal voltage. Because it moves the operating power factor with voltage, there is no single power factor to enter, which is what worst-case impedance is for.
Curtailment: Generation lost when an inverter reduces output or disconnects rather than exceed its voltage limits. Cable voltage rise adds directly to grid voltage, so a marginal cable turns high-voltage days into lost kilowatt-hours.
Worst-case impedance: Using Z = the square root of (R squared plus X squared) rather than R times cos phi plus X times sin phi. It is the largest value the power-factor form can take, so the result bounds every power factor the inverter could be commanded to.
DNSP: Distribution Network Service Provider: the network operator that owns the low-voltage network at the point of supply and approves the grid connection. Most require the voltage rise calculation as part of the connection application.
Final subcircuit (inverter cable): The a.c. cable from the inverter to the board it connects at. Each inverter has its own, and it carries only that inverter's current, unlike the submain and consumer mains which carry the aggregate of every inverter.

Reviewed by

Wisam Tozah: Associate Electrical Engineer. B.Eng (Electrical), MIEAust, CPEng, NER, NSW DBP, NSW PRE, APEC, IntPE(Aus). See how these calculations are verified. LinkedIn. Updated 5 September 2026.

Voltage rise questions, answered

Did AS/NZS 4777.1:2024 change the 2% voltage rise limit?: No. Standards Australia published AS/NZS 4777.1:2024 in August 2024, superseding the 2016 edition, but the voltage rise requirement carries over unchanged: Clause 3.3.3 still caps the overall rise from the point of supply to the inverter a.c. terminals at 2% of the nominal voltage at the point of supply, assessed at the rated current of the inverter energy system. The clause number, the 2% figure and the 4.6 V single-phase / 8 V three-phase line-to-line equivalents are all the same. This calculator applies the 2024 edition. Check your DNSP connection rules as well, because several networks impose a tighter limit (commonly 1%) than the Standard.
What is the AS/NZS 4777.1 voltage rise limit for solar inverters in Australia?: AS/NZS 4777.1:2024 Clause 3.3.3 requires that the voltage rise from the point of supply to the inverter a.c. terminals (the grid-interactive port) does not exceed 2% of the nominal voltage at the point of supply, calculated using the rated current of the IES. For 230 V single-phase that is 4.6 V; for 400 V three-phase that is 8 V line-to-line (or 4.6 V line-to-neutral). The limit applies to the entire inverter path (inverter cable plus any final subcircuit, submain and consumer mains in series back to the point of supply) not to each segment separately, and it applies in addition to the AS/NZS 3000 voltage drop requirements.
How is voltage rise calculated for a grid-connected solar PV inverter?: Per AC cable segment ΔU = K × I × (R·cosφ + X·sinφ) × L, where K = 2 for single-phase (active plus neutral return) and K = √3 for balanced three-phase, I is the rated current of the IES in amperes (AS/NZS 4777.1 Clause 3.3.3 specifies the rated current of the IES, not a reduced figure), R and X are the conductor resistance and reactance per metre from the AS/NZS 3008.1.1:2025 impedance tables at the insulation operating temperature, L is the cable route length in metres, and φ is the inverter operating power factor angle. At worst case the bracket is replaced by the impedance magnitude √(R² + X²). The segment rises are summed across every cable from the inverter to the point of supply, divided by nominal voltage, and compared against the 2% AS/NZS 4777.1 limit.
Does the 2% AS/NZS 4777.1 voltage rise limit include the consumer mains?: Yes. AS/NZS 4777.1 Clause 3.3.3 measures the rise from the point of supply to the inverter a.c. terminals: the network connection point at the consumer mains origin. The consumer mains, submain, final subcircuit and inverter AC cable are all in that path, so their voltage rise contributions add together. Once you set the inverter connection point, the calculator includes every segment in the path automatically.
How do I reduce voltage rise on a solar PV installation that fails the 2% limit?: Work the mitigation hierarchy from cheapest first: (1) shorten the AC cable run; (2) increase the cable cross-sectional area on the segment with the largest absolute rise. Doubling CSA roughly halves rise on that segment; (3) switch from single-phase to three-phase inverters where supply allows (cuts current by ~3×); (4) move the inverter connection upstream (e.g. MSB instead of final board); (5) choose copper over aluminium for the inverter cable; (6) cluster smaller inverters across different boards; (7) request a DNSP tap change or feeder upgrade as a last resort.
Does an export-limited inverter still have to satisfy the 2% voltage rise limit?: Yes: the 2% limit always applies. By default AS/NZS 4777.1 Clause 3.3.3 says the rise is calculated from the rated current of the IES, not a reduced export figure, so an export-limited inverter is still assessed at its rated current unless the network agreement says otherwise. The standard's one allowance is for an aggregate IES rating above 30 kVA, where the site's known minimum load may be taken into account. Where your DNSP accepts a compliant AS/NZS 4777.2 hard export limit for the rise calculation, the calculator's Export Limit toggle applies the limited kW to the consumer mains only: the one segment beyond the export-limit measurement point, with the submains and each inverter cable still assessed at full output; otherwise size on the full IES rated current.
How does the calculator handle multiple inverters on the same installation?: Add each inverter with its own size, name and AC cable run; the connection point (MSB direct or via a DB) is set once for the installation and is shared by every inverter. The tool aggregates currents per segment: the consumer mains and, where used, the submain carry the sum of all inverters, while each inverter's own final subcircuit carries only its own current. The final pass/fail verdict checks the worst-case inverter path against the 2% AS/NZS 4777.1 limit.
What is the difference between voltage drop and voltage rise?: Voltage drop occurs on cables supplying loads (current flows consumer-mains to load) and is governed by AS/NZS 3000:2018 Cl. 3.6.2, which sets a 5% limit from the point of supply to any point in the installation (a note to that clause allows more where supply comes from a substation forming part of the installation). Voltage rise occurs on cables exporting from generation (current flows inverter to point of supply) and is governed by AS/NZS 4777.1:2024 Cl. 3.3.3 with a 2% inverter-path limit. The same cable on the same install has both (drop under maximum demand and rise under maximum export), but they are assessed separately: this calculator covers the AS/NZS 4777.1 inverter-path voltage rise, while the ElecAS Voltage Drop calculator covers the load-side drop.
Should I use worst-case power factor for AS/NZS 4777.1 voltage rise?: Yes, wherever the inverter is configured for any AS/NZS 4777.2 reactive response mode (volt-var, fixed PF other than unity, PF response), because the operating PF then moves with terminal voltage and is not a fixed number you can enter. Worst Case mode uses the impedance magnitude Z = √(R² + X²), which is the maximum value R·cosφ + X·sinφ can take at any power factor, so the reported rise bounds every PF the inverter could be commanded to. Turn it off and enter a power factor only when the inverter is locked to a known fixed PF by the DNSP connection agreement.
Does AS/NZS 4777.1 require a combined voltage drop and voltage rise check?: Not as a single combined calculation. AS/NZS 4777.1 Clause 3.3.3 states that its 2% voltage rise requirement applies in addition to the voltage drop requirements of AS/NZS 3000, so the two are assessed separately and both must be satisfied: the AS/NZS 3000 load-side drop (up to 5%) under maximum demand, and the 2% inverter-path rise under maximum generation. The underlying aim is to keep the consumer's utilisation voltage inside the AS 60038 range, with the point of supply held at or below 253 V (230 V +10%). This calculator covers the AS/NZS 4777.1 inverter-path voltage rise only; for the load-side drop and maximum demand use the ElecAS Voltage Drop and Maximum Demand calculators.
What cable size do I need for a 5 kW single-phase solar inverter to satisfy the 2% voltage rise limit?: A 5 kW single-phase inverter exports about 21.7 A continuous at 230 V, and the 2% limit gives it a 4.6 V budget for the whole path. For copper multicore cable with 90 °C insulation (V-90 or X-90) at worst-case impedance, 4 mm² covers roughly 17 m of total path, 6 mm² about 26 m, 10 mm² about 45 m and 16 mm² about 71 m. In 75 °C V-75 the same sizes reach about 18 m, 28 m, 47 m and 75 m. Those lengths are the whole run added together (inverter cable plus any submain plus the consumer mains), not per segment. The ElecAS calculator returns the actual smallest standard size after applying the AS/NZS 3008.1.1:2025 impedance values and the AS/NZS 4777.1 2% limit to your specific install.
Does cable temperature affect voltage rise?: Yes. AS/NZS 3008.1.1:2025 publishes its conductor impedance tables (Tables 4.1 to 4.10) at the maximum continuous operating temperature of each insulation class: 75 °C for V-75 PVC, 90 °C for V-90 PVC, X-90 XLPE and R-90 elastomer, and 110 °C for X-110 XLPE and R-110 elastomer. Resistance rises ~0.4% per °C in copper, so an XLPE inverter cable at 90 °C exhibits a few percent more rise than the same conductor sized in V-75 PVC. The ElecAS calculator selects the correct temperature row automatically based on the chosen insulation.
What size AC cable do I need for a 6.6 kW solar system?: First check what the 6.6 kW refers to. On most Australian residential systems it is the panel array, paired with a 5 kW inverter, and AS/NZS 4777.1 Clause 3.3.3 assesses voltage rise at the rated current of the inverter energy system: so that system is sized on the 5 kW inverter, about 21.7 A, and 6 mm² copper covers roughly 26 m of total path with 10 mm² reaching about 45 m. Where the inverter itself is rated 6.6 kW it draws about 28.7 A, and the same cables cover about 20 m and 34 m. Those lengths are the whole path added together (the inverter cable plus any submain plus the consumer mains), for copper multicore cable with 90 °C insulation at worst-case impedance. Enter your actual segments in the calculator for the size that applies to your run.
Why does my solar inverter keep tripping or shutting down on sunny days?: The usual cause is high terminal voltage, and cable voltage rise is the part of it a designer controls. The inverter sees the network voltage at the point of supply plus the rise its own cable adds. On a clear afternoon the local feeder is already near the top of the AS 60038 range because every system in the street is exporting, so a cable adding several volts of its own can push the inverter past its AS/NZS 4777.2 limits. Before it disconnects it will usually curtail first (volt-watt response), which shows up as a flat top on the output curve rather than an alarm. Run the installation through this calculator: if the total rise is at or near 2% the a.c. cable is a genuine contributor, and going up one size on the segment with the largest absolute rise is normally the cheapest fix. If the rise is well under 2%, the problem is upstream network voltage and the DNSP needs to be involved.
Do battery, hybrid and multi-mode inverters have to meet the 2% voltage rise limit?: Yes. AS/NZS 4777.1 applies to the grid connection of energy systems via inverters generally, not to solar PV specifically, so a battery inverter, a hybrid PV and battery inverter or a multi-mode inverter is assessed the same way: 2% of nominal from the point of supply to the inverter a.c. terminals, at the rated current of the inverter energy system. What changes is the current. A battery inverter is often rated for a higher continuous a.c. discharge than the PV inverter beside it, and it can hold that output at any time of day rather than only around solar noon, so it is not safe to assume the PV case is the worst one. Enter each inverter in the calculator with its own a.c. rating and cable run and the shared segments are aggregated automatically.
My DNSP requires 1% voltage rise instead of 2%. Can I calculate that?: Yes. Switch the calculator to Advanced and enter the network's figure in the Max Rise field. Everything downstream follows it: the pass/fail verdict, the per-segment breakdown, the suggested minimum cable sizes and the exported PDF all run against the limit you set rather than the 2% default. Several Australian networks apply a tighter allowance than AS/NZS 4777.1 through their connection agreement or service and installation rules, usually on feeders already known to run high, and the tighter figure governs where it applies. On a 230 V single-phase supply a 1% limit is 2.3 V for the whole path, which roughly halves every maximum length in the tables on this page.
What is the maximum AC cable length for a solar inverter?: There is no single figure: the limit is a voltage budget, not a distance, so the answer depends on the inverter current and the conductor. AS/NZS 4777.1 gives the whole path 2% of nominal, which is about 4.6 V on 230 V single-phase. For copper multicore cable with 90 °C insulation at worst-case impedance, a 5 kW single-phase inverter reaches about 17 m on 4 mm², 26 m on 6 mm², 45 m on 10 mm² and 71 m on 16 mm². A 10 kW three-phase inverter on the same sizes reaches about 54 m, 81 m, 137 m and 217 m, because three-phase carries roughly a third of the current for the same kW. Those numbers are the total of every cable between the inverter and the point of supply, so the consumer mains and any submain come out of the same budget before the inverter cable gets what is left.
Do I calculate voltage rise from the panel kW or the inverter kW?: The inverter. AS/NZS 4777.1 Clause 3.3.3 assesses the rise at the rated current of the inverter energy system, and the a.c. cable only ever carries what the inverter puts out. An oversized array (a "6.6 kW system" on a 5 kW inverter is the standard Australian example, and CEC rules allow the array to exceed inverter rating by up to a third) does not increase the a.c. current: it makes the inverter hold its rated output for more hours of the day. So enter the inverter's continuous a.c. rating in kW, and where several inverters share a board, enter each of them so the shared submain and consumer mains are assessed on the aggregate.
Does the AS/NZS 4777.1 voltage rise limit apply in New Zealand?: Yes. AS/NZS 4777.1 is a joint Australian and New Zealand standard, and the Clause 3.3.3 2% inverter-path limit reads the same on both sides of the Tasman. New Zealand also shares the AS 60038 nominal voltages (230 V single-phase, 400 V three-phase) and uses AS/NZS 3008.1.1 for conductor impedance, so this calculator applies unchanged. What differs is the connection process: the local lines company sets its own distributed generation application requirements, and may apply a tighter voltage rise allowance than the standard, which you can enter in the Max Rise field in Advanced mode.
Can I use aluminium cable for solar inverter AC connections?: Yes: aluminium is permitted under AS/NZS 3000 for solar inverter AC cables, particularly on larger commercial systems where the mains and submain are already aluminium. Aluminium has roughly 1.6× the resistance of copper for the same cross-section, so it contributes more voltage rise per metre, and the calculator restricts it to the 75 °C and 90 °C insulation classes (V-75, X-90, R-90) because 110 °C aluminium is not manufactured in Australia. Aluminium sizes also start at 16 mm². Always confirm aluminium-rated terminations on the inverter, isolator and switchboard: many smaller residential inverters specify copper-only terminations.