EG4 › Problems
EG4 PV terminal block or combiner found melted or charred
A PV terminal block in the inverter, or a combiner box on the array wiring, is found melted or charred, sometimes after production dropped and strings went offline. This page covers what to check first and the cause behind it.
What to check first
- Note whether solar production dropped suddenly and strings went offline on and off before the damage was found.
- Ask your installer to inspect any plastic combiner box on the array wiring for melting, cracking or signs of water getting in, even if the breaker on that circuit never tripped.
- If the PV terminal block inside a FlexBOSS21 is found melted, contact EG4. It approved a warranty replacement for that, pending failure analysis of the damaged unit.
Safety. An overheating PV connection can melt and char the inverter's PV terminal block, and a combiner box on the array wiring can melt without the breaker on its circuit ever tripping.
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.