Warning What does this mean?

Your system is down or running degraded, but this is not an immediate safety danger. Work through the safe steps below.

GoodWe Inverter Error 14 — What It Means & What to Check

GoodWe error 14 (“Isolation Fail”) means the inverter measured the insulation resistance between your solar panels and earth as too low — in other words, it suspects electricity could be leaking where it should not. The inverter shuts down as a safety precaution. This often happens in damp conditions and can clear when things dry out, but a persistent error 14 needs a solar professional to find the leak.

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?

What this code means

GoodWe's XS series user manual lists error 14 as “Isolation Fail,” described as “ground insulation impedance is too low.” Every grid-tied inverter continuously monitors the electrical insulation between the DC side — your panels and their cabling — and earth. Think of it as a safety watchman: as long as the panels are well isolated from ground, everything is fine. When that isolation drops below the inverter's safety threshold, the inverter raises error 14 and stops feeding power.

Low insulation usually means moisture has found its way in somewhere — damp panel junction boxes, wet or ageing DC cable insulation, condensation inside connectors, or water around roof cable entries. That is why error 14 loves rainy days, heavy morning dew, and humid climates: it often appears at dawn and clears by midday as the sun dries things out. But it can also come from damaged cable insulation (rodents, UV ageing, cables pinched during installation), a cracked panel backsheet, or a failing panel — causes that do not dry out and only get worse.

This is a safety fault, not just a production fault. The inverter is telling you the array may no longer be properly isolated from earth, which is a potential shock hazard for anyone working on the roof or touching array metalwork. Never try to investigate the array yourself. Note when the fault appears — the weather, the time of day, whether it clears — because that pattern is exactly what your technician will ask about, and it often points straight at the cause.

What is this downtime costing you?

Rough estimate while your system isn't producing. Adjust the numbers to match your setup.

System size (kW) Peak sun hours / day Electricity rate ($/kWh)

–per day

–per week

–per 30 days

≈ – 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 ingress in panel junction boxes or DC connectors — the most common cause; rain, dew, or high humidity lowers insulation resistance.
Ageing or damaged DC cable insulation — UV degradation, rodent damage, or cables pinched or abraded during installation.
Cracked or degraded panel backsheets — older panels can develop insulation breakdown that worsens over time.
Water pooling around roof penetrations or cable entries — standing water wicks into connections.
Poor earthing or bonding of the array frame — GoodWe's troubleshooting includes checking the earth connection of the array, since bad bonding can affect the measurement.
Internal inverter measurement fault — rare; considered only when the array itself tests clean.

Safe steps to try

Work top to bottom, ticking off each step as you complete it. 0 of 5 done.

1. Note exactly when error 14 appears — after rain, at dawn, or in dry conditions — and whether it clears by itself.
2. Do nothing to the array or the inverter wiring yourself — this is a safety fault and the roof and DC side are pro-only.
3. If the fault appeared during wet weather, wait for dry conditions and see if the inverter recovers on its own; many transient isolation faults clear as moisture evaporates.
4. Check your monitoring app for how long the fault lasted and how much production was lost — this helps the technician judge urgency.
5. If error 14 appears in dry weather, keeps returning, or never clears, call your solar installer.

Is your inverter still under warranty?

Before paying for a repair, check — your installer may fix this free.

Brand Year installed

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

Call your solar installer if error 14 appears in dry conditions, returns repeatedly, or never clears. A technician will isolate the DC side and measure the insulation resistance of each string to earth — GoodWe's own guidance treats impedance below the threshold as a wiring fault to be found and fixed, and checks the array's earth bonding too. Never go on the roof, disconnect DC connectors, or measure anything yourself: the DC side stays live in daylight and only qualified personnel may work on it. If this fault ever appears together with a burning smell, smoke, or visible damage, switch the system off via the documented shutdown procedure and call a professional immediately.

Frequently asked questions

Will GoodWe error 14 clear by itself?

Often, yes — if moisture is the cause, the fault typically clears once the array dries out. But “it cleared” does not mean “it is fixed”: if it keeps coming back, the underlying leak is still there and likely getting worse, so get it diagnosed.

Is error 14 dangerous?

It can be. Low insulation means electricity may be finding an unintended path to earth — a shock risk for anyone touching array metalwork. The inverter shuts down to protect you. Stay off the roof and away from the array, and call your installer.

Can rain really cause an inverter fault?

Yes — this is one of the most weather-sensitive faults in solar. Damp connectors and junction boxes are the classic trigger, which is why error 14 often shows up on wet mornings and vanishes by the afternoon.

Will I lose much generation while error 14 is active?

Only while the fault is active. Brief morning appearances cost you almost nothing; an error 14 that holds the inverter off all day is real lost production — and a sign to call your installer promptly rather than waiting.

Need a professional?

This fault may need professional diagnosis. Contact a qualified solar electrician in your area.

Sources: meaning and troubleshooting verified against the manufacturer's documentation — GoodWe GW XS Series Grid-Tied PV Inverter User Manual (EN), official GoodWe manual hosted on emea-test.goodwe.com (GoodWe EMEA download site) — Section 5.4/5.3 Error Message table: 14 = “Isolation Fail”, “Ground insulation impedance is too low”; 15 = “Vac Failure”, “Grid voltage out of permissible range”; 17 = “PV Over Voltage”, “Overvoltage at DC input”; 23 = “Utility Loss”, “Utility is unavailable”. Troubleshooting procedures for Isolation Failure (impedance measurement thresholds, earth-bonding checks) per GoodWe's official GW series user manual (admin.goodwe.com).