Dc mini breaker confusion

[guidecca]

Wires in PV rack could short due to pinching or rodents.
Pigtails between plastic combiner box and MC fuse holders not as likely, consider what is around them.
Often, combiner box has fuse holders or breakers inside.

Can a pigtail from a 12 awg solar panel wire to an inline MC4 fuse and combiner box be sized larger, like 10 awg or 8 awg? In order, solar panel and 12 awg solar panel wire, then MC4 inline 20A fuse, then 10 awg pigtail, then positive and negative busbars inside the combiner box.

 

[Hedges]

Sure, thicker wires is fine.

Big issue these days is that MC4 is not MC4 is not MC4. They're known for causing fires when mix-n-match.
MC4 is only UL listed when mated with select models it has been tested with. So there are several clans of MC4, each of which can work only within its own clan.

PV panel data sheets these days list the limited number of MC4 brands/models they are allowed to mate with.

Betcha there isn't even a brand/model for the MC4 integrated in the MC4 fuse holder.
If you want to do this by the book, use MC4 connectors in compliance with data sheet specs of PV panel, run the pigtail wires through glands into combiner box, and connect to screw terminals of fuse holders.

Breakers, maybe. But don't get me started on those. Previously, "polarized" breakers were sold for that purpose, hopefully labeled "+" and "-" so you connect to the correct end, except neither end was correct. Look for non-polarized breakers to have a safe installation.

 

[guidecca]

Sure, thicker wires is fine.

Big issue these days is that MC4 is not MC4 is not MC4. They're known for causing fires when mix-n-match.
MC4 is only UL listed when mated with select models it has been tested with. So there are several clans of MC4, each of which can work only within its own clan.

PV panel data sheets these days list the limited number of MC4 brands/models they are allowed to mate with.

Betcha there isn't even a brand/model for the MC4 integrated in the MC4 fuse holder.
If you want to do this by the book, use MC4 connectors in compliance with data sheet specs of PV panel, run the pigtail wires through glands into combiner box, and connect to screw terminals of fuse holders.

Breakers, maybe. But don't get me started on those. Previously, "polarized" breakers were sold for that purpose, hopefully labeled "+" and "-" so you connect to the correct end, except neither end was correct. Look for non-polarized breakers to have a safe installation.

Stäubli, formerly named Multi-Contact – the “MC” in MC4 – invented the PV connector in 1996 and remains the holder of the MC4 trademark. https://www.staubli.com/us/en/news/...tified-MC4-Cable-Coupler-for-6-AWG-Cable.html

Connector Stäubli MC4-Evo2, Hanwha Q CELLS HQC4, Amphenol UTX, Renhe 05-8, JMTHY JM601A; Tongling Cable01S-F, IP68 or Friends PV2e; IP6 from the Q-PEAK panel data sheet.

Good possibility that these connectors are rated at 30A. Should be able to keep 30A away from it if fuses are compatible with their connectors.

 

[Hedges]

Ratings up to 70A.
Could be used for home run after combiner, for moderate size arrays.

https://www.staubli.com/content/dam/spot/SOL-Main-11014092-en.pdf#page=10

 

[guidecca]

Ratings up to 70A.
Could be used for home run after combiner, for moderate size arrays.

https://www.staubli.com/content/dam/spot/SOL-Main-11014092-en.pdf#page=10

You hit the goldmine. I wonder if this is the fuse. It doesn't look like the ones I bought. Connector clips:

What Are The Different Types Of Solar Panel Connectors?

Here you will learn about the different types of solar connectors, types of connectors, the difference between the MC3 and MC4, and how to crimp the connectors.

www.semprius.com

 

[Hedges]

I had seen fuse holders with MC4 integrated.
Your pic has them on a pigtail, so could have good MC4 connectors.

Note that the fuse holder is not touch-safe, only the MC4 connector is.
Shut off current and disconnect MC4 connectors on both ends before opening fuse holder.