Thoughts please on circuit design

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octopusman

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I will be mounting 12 panels on an outbuilding in the garden - this will be split into 2 strings of 6 panels each. I have purchased a 3.6kW single phase inverter. The inverter will be affixed to the house 50m away, using 6mm solar DC cable. I was wondering if you could review the circuit diagram/ specs in the attached image, and share any questions/ critique ahead of me purchasing the rest of the stated components. I am self taught and this is a home project for me so please be kind, thanks in advance!

Reference information
PV Panels model: Canadian Solar CS3L-380MS-MC4, datasheet here
Inverter mode: Solis SOL-3.6K-RHI-48ES-5G-DC, datasheet here
20221120_163557.jpg
 
Why have you got the combiner box? Completely unnecessary.
Hi binky, thanks for your speedy reply. So technically my 'combiner box' isn't combining as it is 2 in 2 out, it is more to host the protective devices shown on my diagram. Also I believe Solis recommend some kind of isolation/breaker between the panels and the inverter which presumably helps when the solar panels need isolating away to perform maintenance on the inverter. Online I had read that a combiner box 'provides overcurrent and overvoltage protection to enhance inverter protection and reliability'. Also for 'rapid shut down purposes in case of sudden fluctuations in the current'. Though I also see now mentions that for two string residential installations one isn't required. So I am a bit baffled why 1 or 2 strings systems are considered 'immune' from these issues.
 
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Hi binky, thanks for your speedy reply. So technically my 'combiner box' isn't combining as it is 2 in 2 out, it is more to host the protective devices shown on my diagram. Also I believe Solis recommend some kind of isolation/breaker between the panels and the inverter which presumably helps when the solar panels need isolating away to perform maintenance on the inverter. Online I had read that a combiner box 'provides overcurrent and overvoltage protection to enhance inverter protection and reliability'. Also for 'rapid shut down purposes in case of sudden fluctuations in the current'. Though I also see now mentions that for two string residential installations one isn't required. So I am a bit baffled why 1 or 2 strings systems are considered 'immune' from these issues.
It's all built into the inverter, don't waste your money and time. Fit a DC isolator by all means, it does make fault finding easier down the line. NB there's a lot of drivel on the internet, and a lot of the information is for different countries with different standards and out of date.
 
It's all built into the inverter, don't waste your money and time. Fit a DC isolator by all means, it does make fault finding easier down the line. NB there's a lot of drivel on the internet, and a lot of the information is for different countries with different standards and out of date.
Good point there, thank you. How about the other components I have put in the circuit?
 
I see a DC breaker. I think there should be one on each string before entering the inverter.

Maybe if you have updated your diagram, post it again for another peer (Binky) review :)
 
My installer showed a string DC isolator on his diagram of my system, but the string cables plug straight into my inverter (Solis hybrid, 2 strings).
When queried, he says the isolator on his diagram is the one on the inverter it's self. Is this acceptable do you think?
 
My installer showed a string DC isolator on his diagram of my system, but the string cables plug straight into my inverter (Solis hybrid, 2 strings).
When queried, he says the isolator on his diagram is the one on the inverter it's self. Is this acceptable do you think?
It is, I've done that many times.
 
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