One possibility is a poor contact. This could dissipate as much power as the entire string produces - up to several kW for some systems, but your case looks like just one or two panels, a few hundred watts.
Another is an overheated bypass diode. That should only be a problem with a string of multiple panels in series, and shading over some cells. This would be expected to dissipate about 1.1V x current, about 7W for one string. If you wired multiple strings in series and in parallel, if done wrong you could boost that current.
Is it open-circuit now? Looks like that connector on the left went open-circuit, could have pulled a flame. That might have been a mechanical failure.
Here's a different brand with similar problem:
Solar-Fabrik to issue junction box failure warning on risk of fires
German PV module manufacturer Solar-Fabrik expects to issue a warning in the next few days regarding junction box failures on its solar panels that could lead to fires.www.pv-tech.org
Yes. Fuses needed between parallel panels. I used a Blue Sea block. I tried those MC4 fuse holders. They suck. This worked for each 4 panels. https://www.bluesea.com/products/5045/ST_Blade_Compact_Fuse_Blocks_-_4_Circuits
Circuits | 4 |
Maximum Amperage
| 100A per block 30A per circuit |
Maximum Voltage | 32V DC |
For now I disconnected the panel. Trina said they are going to send a replacement.
They are wired in 3's. I have 4 sets.
Thanks for the information.