EG4 › Problems
EG4 inverter shows PV Isolation low or a PV grounding warning
An EG4 inverter shows PV Isolation low or Warning 20 (PV grounding), coming back in the early morning or stopping the inverter in daylight. This page covers what the codes mean, what to check first, and the cause behind it.
Error codes that go with this problem
| Code | What it means |
|---|---|
| PV Isolation low, W020 or Warning 20 | PV Isolation low, a warning about the PV input. The 12000XP manual lists it as W020, and it is also called Warning 20 (PV grounding). |
What to check first
- Note when the warning comes up and whether it clears on its own. On an 18kPV it came up in the early morning before real sun and cleared each time.
- On a 12000XP that stops with Warning 20 in daylight, note whether switching the PV breaker off clears it.
- If it keeps coming back, have the PV string wiring inspected for damage. EG4 support recommends checking the strings on MPPT 1, then on MPPT 2.
The causes and the fixes
Partners see the causes behind this problem, most common first, the checks that tell them apart, and the fix for each, with part numbers and recent prices when a part is involved.