Photovoltaic inverter displays isolation error

Why is my solar inverter showing a low PV Isolation Fault?

If you’re noticing your solar inverter is showing the error code “low PV isolation, ground fault or isolation fault” in the morning or just after rain. Its likely your solar panels are starting to fail. The moisture from the dew in the morning or rain causes the DC of the solar panels to leak to the earth on the array frame.

Why does my SolarEdge inverter display an isolation error?

Every time the SolarEdge inverter enters operational mode and starts producing power, the resistance between ground and the DC current-carrying conductors is checked. The inverter displays an isolation error when it detects a total combined isolation resistance of less than 600kΩ in single phase inverters, or 1MΩ in three phase inverters.

What is an Isolation Fault in a SolarEdge system?

Modules with defective module isolation, unshielded wires, defective power optimizers, or an inverter internal fault can cause DC current leakage to the Ground (PE - protective earth). Such a fault is also called an isolation fault. This document describes how to identify and locate an isolation fault in a SolarEdge system.

How do I know if my inverter has an Isolation Fault?

You can identify an isolation fault using either SetAPP or the inverter LCD display. An isolation fault may disappear and recur after a short period (especially if it is caused by morning moisture), therefore it is recommended to troubleshoot the fault as soon as it occurs before it disappears.

Why does my SolarEdge TerraMax inverter display an isolation error?

Each time that the SolarEdge TerraMax Inverter enters operational mode and begins producing power, the resistance between the ground and the DC current-carrying conductors is checked. The inverter displays an isolation error when it detects a total combined isolation resistance of less than 50 kΩ. You can identify an isolation fault using SetApp.

Can a transformer-less inverter cause DC current leakage?

In photovoltaic systems with a transformer-less inverter, the DC is isolated from the Ground. Modules with defective module isolation, unshielded wires, defective power optimizers, or an inverter internal fault can cause DC current leakage to the Ground (PE - protective earth). Such a fault is also called an isolation fault.