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GoodWe Isolation Failure

Updated June 2026 · Reviewed for technical accuracy · ~3 min read

Isolation Failure (error 14) means the GoodWe measured low insulation resistance between the DC (solar panel) wiring and earth, in other words a possible ground fault. It is a safety check: if current could leak to earth, the inverter stops. There is a very common, very telling pattern to watch with this one: does it only happen after rain?

The rain clue

If Isolation Failure shows up after rain or in damp mornings and then clears as things dry, the usual culprit is water inside a rooftop DC isolator or a damp connector. That is a known weak point on many rooftop solar systems. The proper fix is to dry it out and reseal it, which is an installer's job, not a quick reset.

What usually causes Isolation Failure

  • Moisture in the rooftop DC isolator or a connector, especially after rain.
  • Damaged or aged cable insulation letting current leak to earth.
  • A grounding (PE) problem in the array or system earth.
  • A faulty panel or junction with degraded insulation.

What to do, safely

Inspection is for the pros Working on DC wiring, isolators and grounding is an installer job, and PV strings are live in daylight. Your safe role is to note the pattern and let it self-clear once.
  1. Note the pattern. Does it appear after rain or in the morning, then clear as the day dries? That strongly points to moisture in an isolator or connector.
  2. Let it self-clear or power-cycle once. AC off, then the DC isolator, wait 5 minutes, restart. A moisture-driven one often clears as things dry.
  3. If it persists, especially in dry weather, stop. A steady Isolation Failure is a genuine insulation or grounding fault. Don't keep resetting it.
  4. Call your installer. They find the wet or damaged point (often the rooftop isolator), dry and reseal it or repair the wiring, and measure the insulation.
When to bring in a professional Insulation faults are a safety matter (leakage to earth). A persistent or dry-weather Isolation Failure should be inspected by a licensed installer, not cleared and ignored.

Related GoodWe codes

Ground Failure, Leakage Arc Fault, DC arc PV Over Voltage

FAQ

Isolation Failure only shows after rain.

That is the classic sign of water in a rooftop DC isolator or a damp connector. It clears as things dry, but the lasting fix is for an installer to dry and reseal the isolator, because the moisture will keep coming back otherwise.

Can I dry it out myself?

No. The rooftop isolator and DC wiring are live in daylight and carry dangerous voltage. Drying and resealing it is qualified work for your installer.

Helpful guides

Error codes explained How to safely restart your inverter What is an arc fault

Sources

  • GoodWe inverter user manual and error-message list (Isolation Failure / error 14 = low PV-to-earth insulation; check for moisture or degraded insulation).
  • GoodWe installer documentation.
⚠️ Safety disclaimer. A DC insulation fault is an electrical-safety issue. PV wiring and rooftop isolators are live in daylight. This guide covers noting the pattern and a single safe power cycle only. Inspection and repair must be done by a licensed installer or electrician.