Critical What does this mean?
A safety-rated fault — there may be a risk of electric shock, fire, or equipment damage. Do not try to fix this yourself. Call a qualified electrician.
SolarEdge Inverter Error 8X58: Meaning, Causes & Safe Fix
Isolation fault — the insulation resistance between your PV array and earth has dropped below the safe limit (1 MΩ on three-phase). This is safety-critical: don't touch DC wiring, and get your installer to find the faulty string.
What should I do first?
Two quick questions — we'll point you to the right starting point.
Is this code still showing on your inverter's display?
Is your system producing power right now?
What this code means
Every time the inverter starts producing, it checks the resistance between the ground and the DC conductors. Error 8x58 (three-phase inverters; 2x19 on single-phase) means the combined isolation resistance measured below 1 MΩ, so the PV array is not properly isolated from ground earth. SolarEdge's isolation fault application note warns that troubleshooting involves hazardous voltage levels and must be done by qualified personnel.What is this downtime costing you?
Rough estimate while your system isn't producing. Adjust the numbers to match your setup.
≈ – kWh of lost production per day.
Estimate only — assumes ~80% real-world output vs. nameplate. Actual losses depend on weather, shading, panel direction, and your tariff.
Common causes
- Moisture in a rooftop DC isolator, MC4 connector, or panel junction box (most common — often appears after rain and clears when dry)
- Damaged or degraded DC cable insulation
- A failing solar panel
- A faulty power optimizer
Safe steps to try
Work top to bottom, ticking off each step as you complete it. 0 of 5 done.
Is your inverter still under warranty?
Before paying for a repair, check — your installer may fix this free.
Based on typical standard warranty terms — always confirm with your warranty card or installer paperwork, as terms vary by model, region, and purchase date.
When to call an electrician
Contact your installer: immediately if the fault persists in dry weather, if it returns after every rain, or if you need the system producing urgently. Per SolarEdge: 'Only a certified PV installer must fix the faulty string before connecting it to the inverter.'
Frequently asked questions
Can I reset an isolation fault myself?
The fault often clears on its own once moisture dries. But don't force restarts — if it keeps coming back, the leak is real and needs a professional to find it.
Why does the isolation fault only appear after rain?
Water ingress at a connector, isolator, or junction box lowers the insulation resistance. When it dries, resistance recovers and the fault clears — but the water entry point still needs sealing.
Is an isolation fault dangerous?
It can be — ground faults in PV systems can put hazardous voltage on normally safe metal parts. Treat it as safety-critical and keep away from the DC equipment until it's inspected.
Need a professional?
This fault is a safety risk — do not attempt to fix it yourself. Contact a qualified solar electrician in your area.
Sources: meaning and troubleshooting verified against the manufacturer's documentation — Troubleshooting SolarEdge Systems, Addendum (Europe & APAC), MAN-01-00333-1.1 — Isolation Fault row (three-phase CPU v3.18xx: 121 → CPU v3.19xx: 8x58; 'PV solar array is not properly isolated from ground earth'). Also: SolarEdge Application Note 'Isolation Fault Troubleshooting' (LCD displays 8x58 on three-phase inverters; 1 MΩ limit; qualified-personnel warning).