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Analysis by Marcus & Team

SolarEdge Inverter Error 18x3A AC Grid Surge

Troubleshoot SolarEdge inverter Error 18x3A (AC Grid Surge Line 1). Identify causes, solutions, and safety measures for residential PV systems.

Frequently Asked Questions

•What is the typical AC voltage range for a residential grid in my area?

Consult your local utility company or a qualified electrician to determine the acceptable AC voltage range for your location.

•How often should I inspect my solar panel system?

A visual inspection of your solar panel system should be done at least once a year. More frequent inspections may be necessary in areas with harsh weather conditions.

•What are the potential consequences of ignoring Error 18x3A?

Ignoring Error 18x3A can lead to damage to your inverter, connected appliances, and potentially create a fire hazard. It is crucial to address this error promptly.

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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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Critical Safety Precautions:

High voltage DC and AC circuits are present in PV systems. Improper handling can result in serious injury or death. Always disconnect AC and DC power before working on the system. Verify absence of voltage with a calibrated multimeter. Adhere to NEC 690 and local electrical codes. Qualified electrician mandatory for invasive repairs.

Solution:

1

*Safety First**: De-energize the PV system by disconnecting the AC and DC disconnects. Verify proper operation of rapid shutdown system per NEC 690.12 using a voltmeter.
2

*Visual inspection**: Examine AC wiring connections at the inverter, service panel, and any junction boxes for signs of looseness, corrosion, or damage.
3

*Voltage Measurement**: With the AC disconnect closed (grid power present, inverter OFF), use a calibrated multimeter to measure the AC voltage on Line 1 at the inverter's AC input terminals. Compare this reading with the utility voltage.
4

*SPD Check**: Inspect surge protection devices (SPDs) connected to the AC side for proper functioning. Use an IR thermometer to check for overheating.
5

*Inverter Settings**: Using the SolarEdge SetApp and installer credentials, verify the AC voltage settings in the inverter configuration are correct for the local grid (e.g., 240V). Review the inverter's event log for other voltage-related errors.
6

*Grid Impedance**: Check the grid impedance with a grid impedance analyzer according to IEEE 1547 testing procedure.
7

*Qualified Electrician**: If the issue persists, contact a qualified electrician to inspect the grid connection and perform further diagnostics.

Technical Background:

SolarEdge hybrid inverters synchronize with the AC grid to deliver power. The inverter's anti-islanding protection monitors grid voltage and frequency to prevent backfeeding during outages. Error 18x3A indicates the inverter's AC voltage sensor on Line 1 has detected a voltage exceeding the programmed threshold. The inverter must rapidly disconnect from the grid per UL 1741 and IEEE 1547 standards to protect equipment and personnel. Grid surges can damage inverter components (capacitors, MOVs, IGBTs) and connected loads.

Why This Happens:

Grid voltage fluctuations or instability.
Loose or corroded AC wiring connections.
Faulty surge protection devices (SPDs) on the AC side.
Incorrect AC voltage settings in the inverter configuration.
External electrical events (e.g., lightning strikes, utility switching).
Inverter hardware failure (AC voltage sensor, internal MOV).

Symptoms:

SolarEdge inverter displaying Error 18x3A, indicating an AC grid surge detected on Line 1. The inverter may shut down or reduce power output.

Preventative Care:

Schedule annual inspections of AC wiring connections.
Install and maintain properly sized surge protection devices (SPDs) on both AC and DC sides.
Monitor the inverter's performance and error logs regularly via the monitoring portal.
Ensure the inverter firmware is up to date.
Periodically check grounding connections according to NEC 250.