Fusing REQUIRED?

2oldman wrote:
Few of us fuse panels. Run them in series to avoid amperage issues.

Full sun always?

I'd suggest to install a manual trip circuit breaker between panels and charge controller. You may need to interrupt power from the panels at some time and a breaker with manual trip is made for that.

Bussmann manual reset CB

Fusing makes for more connections, and in turn more resistence, not to speak of more places for corrosion.
No need to fuse panels, period !

I can't remember the name of the fuse maker company that has that link to how to fuse panels. We used that link a few years ago for this topic.

Found it---
http://www.cooperindustries.com/content/dam/public/bussmann/Electrical/Resources/technical-literature/bus-ele-an-10191-pv-app-guide.pdf

It is with more than three strings in parallel that you need to fuse the strings--see page 7 of 35 in that link.

Few of us fuse panels. Run them in series to avoid amperage issues.

Technically each panel has a fuse rating. 15 amps is typical but check the specs. To protect the panel during some internal short you should have fuses on each panel as they enter the combiner box if the total exceeds the fuse rating. Most people seem to skip this.

For the main feed down to the controller there is no fuse needed as the wire chosen would always have the ampacity of the full solar array. Although some install a breaker or switch to cut power for easier service. Removing a fuse is also an option to break the circuit.

Are you asking if larger wire means you don't need fuses? Not a solar expert, but I'd say no.