Combiner box issues

[Bluedog225]

This photo gives you a basic idea of how it should be wired using the components you have. View attachment 213925

I’d like to understand this. What are the components from left to right.

Power in to bus bars
Breakers
Thing? (Surge protection?
Another breaker?

And where is power out?

Thanks

 

[Brett V]

I’d like to understand this. What are the components from left to right.

Power in to bus bars
Breakers
Thing? (Surge protection?
Another breaker?

And where is power out?

Thanks

This picture is a slightly different configuration but lays everything out clearly. Four sets of mc4 connectors for the PV strings, positive going in to individual fuse holders. The fuse holders are combined to a common bus bar which feeds the output circuit breaker and includes a tap to the lightning surge protection device. The negative of the mc4 connectors also tie in to a bus that connects to the output breaker with a tap to the lightning surge protection device. Clean design, pretty straight forward.

 

[Bluedog225]

This picture is a slightly different configuration but lays everything out clearly. Four sets of mc4 connectors for the PV strings, positive going in to individual fuse holders. The fuse holders are combined to a common bus bar which feeds the output circuit breaker and includes a tap to the lightning surge protection device. The negative of the mc4 connectors also tie in to a bus that connects to the output breaker with a tap to the lightning surge protection device. Clean design, pretty straight forward.

Thanks.

Is the purpose of having the fuses and breaker simply for the switch function?

 

[Brett V]

Thanks.

Is the purpose of having the fuses and breaker simply for the switch function?

The fuses protect the PV strings, the breaker is protecting the output and wiring going to the mppt.

 

[Bluedog225]

The fuses protect the PV strings, the breaker is protecting the output and wiring going to the mppt.

Oh. I get it. Because the amperage will be greater going to the MPPT than the individual strings. Right?

I guess I don’t know why people use fuses for the strings and breakers going to the MPPT. As opposed to fuses for both. I’m guessing for the disconnect functionality.

Am I right in thinking it could be all fuses or all beakers? Or mix and match?

Thanks

 

[Brett V]

Oh. I get it. Because the amperage will be greater going to the MPPT than the individual strings. Right?

I guess I don’t know why people use fuses for the strings and breakers going to the MPPT. As opposed to fuses for both. I’m guessing for the disconnect functionality.

Am I right in thinking it could be all fuses or all beakers? Or mix and match?

Thanks

I would guess it doesn't matter as long as they're properly sized. I built the combiner I'm using right now for 5 strings and used 15 amp breakers on each string with a 70 amp breaker on the output.