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Analysis by Marcus & Team

SolarEdge Hybrid Inverter Error 32: AC Voltage Too Low

Troubleshoot SolarEdge Error 32 (AC Voltage Too Low) in residential hybrid inverters. Diagnostic steps, safety warnings, and expert tips for grid-tied systems.

Frequently Asked Questions

•What are the common causes of AC voltage drops in residential solar systems?

AC voltage drops can be caused by undersized wiring, long wiring runs, loose connections, and excessive loads on the same circuit.

•How can I safely disconnect my SolarEdge inverter from the grid?

First, open the AC disconnect switch. Then, open the DC disconnect switch. Verify that the inverter is completely powered down using a multimeter. Follow all applicable safety precautions.

•What NEC code sections are relevant to AC wiring in solar PV systems?

NEC Article 690 covers solar photovoltaic (PV) systems. Refer to NEC 690.8 for circuit sizing and overcurrent protection, NEC 690.9 for overcurrent protection, NEC 690.15 for disconnect requirements, and NEC 310.16 for ampacity of conductors.

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Marcus leads the technical research department at Storage Faults. Together with a team of systems analysts, he specializes in translating complex solar storage error codes into actionable diagnostic steps for the US market.

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Technical Background:

The SolarEdge hybrid inverter synchronizes its AC output with the grid voltage and frequency. Error 32 indicates a failure in this synchronization or a problem with the grid supply. The inverter's internal monitoring system detects when the AC voltage falls below a predefined threshold, triggering the error and initiating anti-islanding protection to prevent current injection into a potentially unstable or offline grid. The inverter's control system uses a PLL (Phase Locked Loop) to maintain synchronization and power factor correction.

Symptoms:

The SolarEdge hybrid inverter reports Error 32, indicating that the AC grid voltage is below the inverter's minimum operating threshold. This may result in the system disconnecting from the grid and ceasing energy production. Backup power functionality may also be affected if battery charging/discharging is dependent on grid availability.

Possible Causes:

Grid voltage fluctuations or brownouts caused by utility issues.
Loose or corroded AC wiring connections at the inverter, service panel, or meter.
Incorrect AC voltage settings configured within the inverter's software.
Excessive voltage drop due to long or undersized AC wiring runs.
Faulty grid monitoring circuitry within the inverter.
External loads drawing excessive current, causing temporary voltage sag.

Solution:

1

*Safety First:** De-energize the AC and DC disconnects for the SolarEdge system per NEC 690.
2

Verify complete power down using a calibrated multimeter.
3

*Visual inspection:** Check all AC wiring connections at the inverter, service panel, and meter for looseness, corrosion, or damage. Tighten or replace connections as needed, adhering to NEC 310.16 wire ampacity guidelines.
4

*Voltage Measurement:** With the AC disconnect closed (system OFF), use a multimeter to measure the AC voltage at the inverter's input terminals. Compare this reading to the nominal grid voltage (e.g., 240V). Document the voltage level.
5

*Inverter Settings Review:** Access the inverter's configuration interface (requires installer access) and verify that the AC voltage settings are correct for the local grid. Adjust the settings if necessary, consulting the SolarEdge system manual.
6

*Wiring inspection:** Check the size and length of the AC wiring run from the inverter to the service panel. Ensure that the wiring is adequately sized to minimize voltage drop under maximum load conditions. Refer to NEC Chapter 9, Table 8 for conductor properties.
7

*Load Analysis:** Identify any large loads operating on the same circuit as the inverter. Temporarily disconnect these loads and re-evaluate the AC voltage at the inverter to see if the problem resolves.
8

*Inverter Replacement:** If all other causes have been ruled out, the inverter may have a faulty grid monitoring circuit and requires replacement. Contact SolarEdge support for warranty assistance.

Safety Warning:

Working with electrical systems involves risk of electric shock and arc flash. High DC voltages (up to 600V or higher) are present in PV systems, even when the AC disconnect is open. Always de-energize the system completely before performing any maintenance or repairs. Qualified electricians must follow all applicable NEC guidelines and use appropriate personal protective equipment (PPE).

Prevention:

• Schedule annual inspections of AC wiring connections to identify and correct any looseness or corrosion.
• Monitor grid voltage regularly using the SolarEdge monitoring portal or a dedicated voltage monitor.
• Ensure that the inverter's firmware is up-to-date to benefit from the latest voltage monitoring algorithms and bug fixes.
• Optimize the placement of large electrical loads to minimize voltage sag on the inverter circuit.

Expert Tip:

Use the SolarEdge SetApp commissioning tool to access advanced diagnostic information, including real-time AC voltage readings and historical grid voltage data. This can help pinpoint the source of the voltage drop and identify any intermittent grid issues.