Fusing single 100W 12V Solar Panel, HQST-100P

[ericj205]

What happens if the leads on a single panel short to each other? Is there a fuse built into the junction box? Should an inline fuse be placed on one of the leads? If so, closest to panel or charge controller?

I have 50' cables running thru an attic and don't want to burn the house down.

 

[gnubie]

If the short has good contact surface area, nothing. You won't damage anything. The panel and wiring is (or should be) rated to handle the peak current output of the assembly since they are used near peak current most of the time.

If the short surface area is small, you'll get local heating at that point. If you draw an arc, you'll get very high temperatures in a pin point and you'll melt the insulation on the wire, and vapourise the wire at the point of the arc. Really. There are demonstrations of this on youtube.

Fusing on a single panel is pretty much pointless as no fuse you can fit, that won't itself significantly limit your electricity production, will blow.

 

[efficientPV]

You only need to fuse panels if there are more than two in parallel. As said before a panel can't produce more current than the Isc. Two or more good panels in parallel can feed significant current to a bad panel at more current than the internal conductors can handle.

 

[PHoganDive]

You only need to fuse panels if there are more than two in parallel. As said before a panel can't produce more current than the Isc. Two or more good panels in parallel can feed significant current to a bad panel at more current than the internal conductors can handle.

The same issue applies to combiner boxes.