L&PE FAIL: AC phase ground fault

This guide helps troubleshoot an "AC Phase Ground Fault (Warning)" on an Autarco inverter. This error indicates a potential ground fault on one or more of the AC phases connected to the inverter.

Why it's problematic

A ground fault represents a serious electrical safety hazard. It occurs when current leaks from the AC wiring to the ground, potentially causing electric shock or damage to equipment.

Possible causes

Damaged AC wiring: Insulation damage, pinched wires, or loose connections can create a path for current to flow to the ground.
Faulty appliances: Malfunctioning appliances connected to the AC circuit can cause ground faults.
Environmental factors: Moisture, corrosion, or rodent damage can compromise the insulation of AC wiring and lead to ground faults.

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: Sometimes, a temporary glitch can trigger the error. Restarting the inverter can clear the fault.
Inspect the AC wiring: Thoroughly check all AC wiring connections between the inverter and the main electrical panel, looking for any signs of damage, looseness, or corrosion.
Measure ground conductor current (Certified Installers Only): Using a clamp meter, a certified electrician should measure the current flowing through the ground conductor to determine if there's a ground fault.
Isolate faulty appliances or circuits: Disconnect appliances or circuits one by one to identify the source of the ground fault.

Verifying the solution

Once the issue causing the ground fault is resolved, the "AC Phase Ground Fault (Warning)" should disappear from the inverter's display. A certified electrician should confirm the absence of ground faults using appropriate testing equipment.

If the problem is not resolved

A persistent ground fault error suggests a serious electrical issue that requires immediate attention from a qualified electrician.

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.