ARC - Fault: Arc in DC circuit

An "ARC Fault" error indicates that the inverter's Arc Fault Circuit Interrupter (AFCI) has detected a potential arc fault in the DC wiring connected to the solar panels. An arc fault is a dangerous electrical discharge that can generate heat, leading to fires.

A single ARC error will only be reported, but the inverter will continue to work. There is no need for immediate action. If more than 5 ARC errors are reported within 24 hours, the inverter will stop completely.

Why it's problematic

Arc faults pose a serious fire hazard, endangering property and lives.
They can cause damage to electrical wiring and equipment.

Possible causes

Loose or damaged DC wiring or connectors.
Deteriorated or worn-out insulation on DC cables.
Moisture or debris intrusion in DC connections.
Rodent damage to wiring.
Incorrectly crimped or installed connectors.
A faulty AFCI module within the inverter.

Before you begin

Safety First: Working with electrical equipment always involves risks. Ensure you are qualified and follow appropriate safety precautions. Disconnect the inverter from both AC and DC sources before performing any physical inspection or adjustments.

Gather Information: Before starting troubleshooting, have the inverter manual on hand. You should also gather information about the inverter model and serial number, the installation date, and the PV array configuration (number of panels, capacity, and number of strings).

Troubleshooting steps

Restart the inverter (up to three times). This can sometimes clear transient faults.
Check for loose or damaged DC connectors and wiring. Carefully inspect all connections between the inverter and the solar panels, including terminal blocks and junction boxes. Look for any signs of overheating, discoloration, corrosion, or physical damage. Ensure that the connectors are securely fastened, and tighten any loose connections.
If the error code points to a specific string, disconnect that string from the inverter and then reconnect it. This can isolate the problematic area.
Inspect the DC cables for signs of wear, tear, or damage to the insulation. Pay extra attention to areas where cables may be exposed to friction, bending, or extreme temperatures. Replace any damaged or suspect cables.
Check for moisture or debris intrusion in DC connections. Ensure that all connections are clean and dry. If you find moisture or debris, clean the affected area thoroughly and allow it to dry completely before reconnecting. Consider applying a weatherproof sealant to outdoor connections to prevent future problems.
If you suspect rodent damage, thoroughly inspect the wiring for any signs of chewing or nesting. Repair or replace any affected cables. Implement rodent deterrents or barriers to prevent future damage.

Verifying the solution

After completing the troubleshooting steps, monitor the inverter's display. The "AFCI Fault" error should clear if the issue is resolved. The inverter should resume normal operation, indicated by the status LED lights and power generation readings on the display.

If the problem is not resolved

If the error persists after following all the steps, the problem may be an internal fault within the inverter, potentially requiring replacement.

As a system owner: In this case, contact the inverter installer or distributor for further assistance. You can find the details of your installer in the MyAutarco app.
As a certified installer: Contact Autarco Support, you can submit a support case via Helios.