Zero Export Solar Inverter Setup: Settings and Tests

Last updated: November 2026

A zero-export system fails in small, quiet ways: a CT clamped backwards, a meter that stops talking, a limit entered in the wrong unit. This guide walks through the settings, metering and wiring checks, then the failure behavior and the tests that show the limit works. It uses the manufacturers’ own manuals for SMA, Fronius, Solis, Growatt and Victron.

This guide covers configuration, commissioning evidence and troubleshooting. Commissioning means the final checks before the system goes live. For control design and equipment choice, start with the zero export device guide. Qualified people must do the electrical work, the setting changes and the tests. They must follow the approved design and the manual for the exact equipment.

What does zero export to load mean?

A zero-export system stays connected to the grid. It is designed so that no extra energy flows into the grid. SMA’s planning guidelines put it this way: all the energy generated is used on site. So the inverter must cut its output to what the site uses at that moment (SMA, Planning Guidelines: PV Systems with Zero Export). That is what “zero export to load” means. The PV feeds the site’s loads and nothing else.

Two limits are easy to mix up. A generation limit caps what the inverter makes. An export limit caps what flows at the connection point after the site has used its share. Zero export needs the second one. So you need a power reading at that point.

Start with a configuration schedule

Before you open an installer app, get the connection approval. Then build a schedule that links each requirement to a device setting and a test. Keep installed PV capacity, inverter capacity and permitted export as three separate numbers.

If you get no payment for export, that does not make a zero-export requirement. Choosing zero export also does not waive an interconnection process. In Great Britain, ENA EREC G100 Issue 2 Amendment 2 (2023) covers customer import and export limitation schemes. It states that generation must also meet the relevant connection rules, including G98 or G99 as they apply.

Check the edition and process your DNO (the local grid operator) requires. A G99 connection is not automatically zero export.

Mark which settings only authorized people may change. Keep a copy of the approved settings before you change anything. Plan a rollback and an escalation route.

Check the signed active-power reading

A CT measures current. To get signed active power, you also need a voltage reference, a phase link and a measurement system. Signed active power is real power with a plus or minus sign for its direction. The CT arrow direction and the sign of the shown value depend on the product. So follow the wiring diagram for your meter and CT.

Check the CT polarity marks, CT ratio, phase assignment, meter role and sign convention. A three-phase meter still needs each current wired to the right voltage phase.

Makers state their own rules. SolarEdge’s US UL 3141 power control system page names a compatible import/export meter at the point of common coupling. That is the point where the site joins the grid. The page lists the SE-MTR480-NN-S-SC meter with Socomec ACTL-1250-600 CTs, with CT arrows toward the PCC. It warns that production and consumption meter roles do not do the export-limiting job.

In Growatt’s MOD TL3-XH manual, “K→L” is printed on the CT. K is on the grid side and L is on the load side (Growatt MOD 3-10KTL3-XH manual). These are two products with their own diagrams. Wire yours from its own manual.

Confirm the measurement boundary covers every source

A meter on a PV feeder measures that feeder. It does not measure the net flow of the whole site. Several things change the power the controller sees. These are existing PV, battery discharge, backup generators, several incomers (incoming supply lines) and separately metered tenants. Mark controlled and uncontrolled sources on the drawing.

Compare the shown import and export direction with a separate power measurement under approved operating conditions. A clamp that reads current only cannot show the direction of active power. It also cannot tell reactive current from active current. Record the method, the instrument and its uncertainty.

Three-phase example: why total and per-phase limits differ

Define import as positive and export as negative. Suppose the measured active power on each phase is:

The site imports 0.5 kW in total (2 - 1 - 0.5) while it exports on two phases. A total-site limit sees import. A per-phase non-export rule sees export on L2 and L3. Which one applies depends on what the connection conditions require. It also depends on what your equipment can control.

Check meter communication and supported controls

Use the meter model listed in the inverter’s compatibility list. An RS485 port or a shared Modbus protocol is not enough. Modbus is a common set of rules that devices use to exchange data. Match the exact meter variant, address, serial settings, scaling, sign, data type and register map to what the maker supports. Do not borrow registers from another meter family.

Take cable type, termination, shielding and baud rate from the manual for your exact meter and inverter. Check live readings and timestamps, communication status and alarms. A reading that stays frozen while the load changes is stale data. Find out whether the system detects stale data as well as a cut link.

With several inverters, find out which device owns the control target. Also find out how each inverter receives commands. A working link to one inverter does not mean every generator is controlled. Write down the controller priorities. Note any link to storage or to limits set by the network.

Brand-specific settings from the manufacturers’ documents

Menu names and defaults change between models and firmware. Treat the summaries below as pointers to the document to follow. Confirm the document matches your model.

SMA

SMA documents several routes, depending on the controller:

• Sunny Home Manager 2.0 with an energy meter. In the Home Manager’s feed-in limitation, zero export is a setting of 0% or 0.000 kW of nominal system power. SMA notes that control cycle times can still let a small amount of energy reach the grid. The inverter parameter Operating mode active power setting must be Active power limitation P via system control or External specification. A limit of 0% works only on inverters with the fallback function. They go back to 0 W output if communication with the Home Manager fails (Sunny Home Manager 2.0 manual).
• Cluster Controller with an SMA Energy Meter. For closed-loop control at the grid connection point, enter 0 under Manual specification for the active power setpoint. To block only active power feed-in, and keep the grid relay closed, set Grid disconnection at 0% specification to No. SMA says to enter 200 for Active power gradient for a control speed of 3 to 10 seconds. It also says feed-in swings within that range, so “0 W” is not exact. A base self-consumption of about 25 W per inverter adds a small control error (SMA technical information on active power control at the grid connection point).
• Parameters for zero export. SMA’s planning guidelines list these settings. External active power setting and External active power setting 2, limitation of change rate and nominal value filter are all off. Activation of plant control based on maximum of active power phase measured value is on. Operating mode active power setting is set to External active power specification. Changes may need an SMA Grid Guard code. Saving can take hours if the inverter is in night mode (SMA Planning Guidelines).

Fronius

The Fronius Primo GEN24 7.7 to 10.0 kW 208 to 240 V operating instructions describe two limits. A total power limit is a fixed feed-in cap for the whole PV system. Dynamic power limitation (soft limit) cuts output when the set feed-in value is exceeded.

The optional hard-limit trip switches the inverter off within 5 seconds if its value is exceeded. That value must be higher than the soft limit. If the Smart Meter connection is lost, the optional fail-safe puts the inverter in standby, so nothing is fed into the grid. Fronius advises against Wi-Fi between the meter and inverter when the fail-safe is on. Short disconnections can shut the inverter down. Without a meter, or if the primary meter has failed, the inverter limits its output to the set maximum feed-in power.

The manual has a section on dynamic feed-in limitation with multiple inverters. Use the manual for your region and inverter family. Do not use one for a Primo or Symo from elsewhere.

Solis

Solis documents different routes by product line. For its S5 hybrid inverters, the service article sets Export Power Set > Backflow Power to 0 W and the function to ON.

For S6 hybrids, you limit export through the app’s internal export power manager. It has a grid feed-in power or current limit and an Unbalanced Output switch. ON feeds power only to the phase with load. OFF evens it out across three phases (Solis, S5 and S6 hybrid zero export set, modified 18 March 2025).

For the US RHI-1P(5-10)K-HVES-5G-US hybrid series, Solis states the inverter cannot achieve zero net export. After a change in demand, there is a reaction time of about five seconds. 10% to 20% of daily PV generation can end up as backflow. Solis suggests adding a battery, reducing PV output or steadying load changes to get close to zero (Solis North America, export power set and failsafe, modified 15 June 2022).

Solis’s Export Power Manager reads the grid-side meter over RS485. It connects over RS485 to an inverter or a daisy chain of inverters (EPM-5G-PRO quick installation guide).

Growatt

The MOD TL3-XH manual says export limitation needs a smart meter. It recommends Growatt’s TPM-CT-G 100A. It also says the inverter’s phase order must match the meter’s, or export limitation will not work. The limit is an ExportLimit Rate in percent of rated power. You set it on the inverter screen or in the app. A Phase levels option gives per-phase limiting (Growatt MOD 3-10KTL3-XH manual).

Victron

In a Victron ESS system, the GX device’s ESS menu has Grid feed-in settings. You can turn off AC-coupled or DC-coupled PV feed-in, or limit the maximum feed-in power. Victron notes the limit is a system target. It can be briefly exceeded after a large load disconnects or solar output jumps.

The Grid setpoint (default 50 W) sits slightly above 0 W to absorb regulation overshoot. For AC-coupled PV, Victron says the feature is designed for Fronius inverters and, per Victron, verified most thoroughly with them, from firmware 3.7.3-2. It also says a Fronius Smart Meter must not be used to limit export in a Victron ESS system. To make a Fronius stop generating when communication is lost, Victron says to configure Dynamic Power Reduction on the Fronius (Victron ESS manual, configuration).

Sungrow, Huawei and other brands

For Sungrow, Huawei, GoodWe or any other brand, get the exact regional manual, the supported-meter list and the commissioning steps for your model and firmware. Do this before you follow a walkthrough. A terminal diagram or menu path for one series does not carry over to another.

If the supplier’s documents do not state compatibility or the failure behavior you need, settle that before acceptance. You may need a supplier-supported retrofit or a different design.

Compare the control routes

The table lists what each maker’s document names. It does not rank the routes. It also leaves out controllers whose documents were not read.

Three-phase and C&I notes

On three-phase sites, first decide if the limit applies to the total across the phases or to each phase. C&I means commercial and industrial. Equipment handles this in different ways:

• SMA’s Cluster Controller takes the cumulative power over all three line conductors for closed-loop control. SMA’s zero-export parameter list includes plant control based on the maximum of the active power phase measured value. That is the phase-exact option.
• Growatt’s MOD TL3-XH manual gives a worked example. Take a 10 kW inverter with a 30% limit. The grid may receive 10 kW × 30% = 3 kW. Say L1 carries a 1 kW load, and L2 and L3 carry none. Standard (total) mode outputs 1.33 kW on each phase. So the grid receives 0.33 kW on L1 and 1.33 kW on L2 and L3, which adds to 3 kW. With Phase levels enabled, each phase is held to 1 kW. The inverter outputs 2 kW on L1 and 1 kW on L2 and L3. The grid receives 1 kW per phase, again 3 kW in total. A negative value reverses the meaning. It then shows the amount the site may draw from the grid.
• Solis S6 hybrids offer Unbalanced Output, described above.

Check the math of any such example against your own load. Three-phase unbalance matters most when large single-phase loads or single-phase generators share the supply. Mark them on the single-line diagram.

Configure the export function, not a look-alike limit

Turn the schedule into the exact model’s settings. Check the unit and reference of each field. Watts, kilowatts and percent of a stated capacity are different inputs. Make sure a zero export target has not been confused with zero inverter output, a fixed generation cap or a billing-meter display choice.

After saving, read the active settings back. Keep a record that shows firmware and device identity, not only a cropped image of a zero value. If the maker requires a restart, check that the setting stayed and the measurements are valid afterward.

Record the fallback clearly. The makers above differ. SMA’s supported inverters drop to 0 W when Home Manager communication fails. Fronius goes to standby only if you enable its fail-safe. Victron’s Fronius setup needs Dynamic Power Reduction configured. Specify, configure and show the fallback working for your project.

Create a commissioning test matrix

Set acceptance criteria before testing. The allowed response time, excursion, measurement basis and protection come from the connection conditions and the equipment scheme for your project.

Plan tests around the site’s essential loads and electrical hazards. Do not tell a customer to open a live service board or switch off every building load. Fault injection and protection tests belong to the approved procedure and the responsible specialists.

Monitoring screenshots may sample too slowly to catch a brief export spike. Choose instruments and logging intervals that suit the acceptance requirement. Record weather, available PV power and site load. That way, a pass at low generation is not read as a pass under all conditions.

Troubleshoot from evidence

Save alarms and timestamped measurements before you go to the maker. Fix wiring or settings only through the authorized procedure. Never reverse live CTs or swap wires as a generic fix. Treat a firmware update as a controlled change. Confirm the supported version and procedure, and keep the configuration record. Then repeat the relevant acceptance checks.

Retrofit and financial review

For a retrofit, find out whether the existing inverter supports the required limit and the measurement and control combination. Ask for a quote that lists each cost on its own: hardware, electrical work, communications, configuration, testing, downtime and any connection-process changes.

A heating diverter or battery can absorb surplus while it has room. That does not make it an accepted export-limitation system. For battery and hybrid choices, see on-grid vs hybrid solar inverters in India.

Use time-matched load and generation to assess curtailment, the PV output you lose to the limit. Annual totals cannot show whether demand exists when PV is available. Storage reduces curtailment only within its charge power, usable energy and state-of-charge limits.

Illustrative energy comparison: an unconstrained annual AC estimate is 14,500 kWh. Of that, 5,075 kWh is used on site and 9,425 kWh (14,500 - 5,075) would be exported. With zero export, unchanged site use and no storage, all 9,425 kWh is curtailed. At an assumed export value of 0.05 currency units per kWh, the lost payment is 9,425 × 0.05 = 471.25 units a year. The inputs are assumptions, so replace them with your tariff and load data.

Do not value all curtailed energy at the retail rate. Do this only if a load-shifting or storage scenario really delivers that energy in place of purchases. Include conversion losses and added costs. Carry the stated assumptions into the financial evaluation workflow.

Handover and change control

The commissioning pack should hold these items:

• the approved as-built drawings
• equipment identities and versions
• meter and CT configuration
• the signed power convention
• active limits and fallback settings
• the test matrix and results
• the measurement method, alarms and acceptance records

Name who monitors faults and who may change settings. Size and label the AC disconnect at the connection point on the same drawings.

After you replace a meter, add an inverter, change a battery, change the network or update firmware, retest the relevant behavior. Record the new configuration. For customer-facing communication, explain the limit, the curtailment assumptions and who is responsible in the solar proposal.

For the drawing itself, see the electrical design and SLD guide. To see your own export-limit scheme on a drawing, book a SurgePV demo.

Frequently Asked Questions

What is zero export solar inverter configuration?

It sets up a supported control system to limit active-power export at the grid connection point. You need valid measurement, compatible equipment, the right settings, a fallback and acceptance tests. Setting the limit to zero is only one step.

What does zero export to load mean?

It means the PV system supplies the site’s loads and nothing flows to the grid. The inverter cuts its output to match what the site is using at that moment. This needs a meter at the connection point.

Which way should a zero export CT arrow point?

Follow the installation diagram for your exact meter and CT. Growatt prints K to L on its CT, with K on the grid side. SolarEdge shows CT arrows toward the point of common coupling for its US UL 3141 system. Check polarity, phase mapping and the sign convention in your manual.

Is total-site zero export the same as zero export on each phase?

No. Import on one phase can offset export on another in the total. Growatt’s MOD TL3-XH manual shows the difference. With a 3 kW limit, total mode can export 1.33 kW on two phases. Its phase-level mode holds each phase to 1 kW.

How do you verify zero export configuration?

Use an approved commissioning plan with set acceptance criteria. Record power measurements. Also record the results of demand changes, available generation, failures, restarts and storage limits. Monitoring screenshots alone can miss short export spikes.

What happens when meter communication fails?

It depends on the equipment and settings. SMA inverters that support the fallback function go back to 0 W if the Home Manager link fails. Fronius goes to standby only if its fail-safe is enabled. Set, configure and test the fallback you need.

Can zero export be retrofitted?

Yes, if the existing equipment supports a compatible control arrangement. Check exact models and firmware, installation work, fallback, testing and connection-process changes before you quote.