What did you use to protect your cables??
15mm black irrigation pipe, got plenty of those here.
And overload protection?
An idea that has been discussed:
Get the right ones though:
Fuses as per panel spec?
So no circuit breakers or surge arrestors??
Sure, you can put surge arrestors in the combiner box. Thatâs usually where I see them. You can put breakers in there as well, if you really want to, but fuses are more commonly used. Cheaper.
Remember also, the panel can only do its I_sc current when you short circuit it, and your fuse/breaker and cable has to be higher than that (by about 20%) anyway. Unless something catastrophic goes wrong, the fuse/breaker is never going to blow. By using breakers, you are implementing an easy-reset which will never be used, and cost you extra money 
MCBâs can also be used for on-load isolation of the circuits. Pulling fuses on-load is do-able but can be a bit scary to some people.
I donât like fuses in this scenario because as you rightly state they have to be just a little bit oversized to have any practical worth. That means you are at the mercy of a nuisance fuse blowing. Now you would be faced with the prospect of spending time fault-finding and waiting until nighttime to replace the fuse.
Of course, you could have faith in your testing and replace the fuse on a possible fault, not just on load.
Which is a whole order scarier.
I like the circuit breaker concept especially if you have combined 2 arrays. See: Undoing overpanelling by adding an MPPT - #13 by Richard_Mackay
I would want to see the current each array is drawing at any stage. This is easily done if you have a CB rather than disconnect fuses or switchesâŚ
Thanks to this thread I have the correct breaker. This will go between the PV Combiner box (fused) and the MPPT. Combiner box is outside and this is located with the rest of the system.
Now for my question: Due to the physical layout of the system it would be easier and neater if the output from the PV Combiner box entered this box from the bottom and went directly into the bottom of the breaker. Does this breaker support load from the bottom?
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I know that AC breakers can have the feed in either at the top or bottom. (Here we tend to feed in at the top but overseas its from the bottom)
With DC breakers Iâm not so sure. They have polarity inputs for positive and negative.
Have a look at the documentation and see if they have instructions itr.
P.S. I copied the documentation on my installationâŚ
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I found this but its not clear to me. There is one diagram where it shows load from the bottom or top.
It is a bi directional breaker, so specifically designed for the load to be on either side.
Just some labelling restictions:
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The EX9BP is polarity independent. So it is not going to matter which side you use for PV/Battery.
What I would do, however, is push the 6mm PV cable behind the DIN rail and loop it over to the top. Looks much neater too. I mean, I assume it will fit. Itâs one of the nice things you can do with DIN-setups that Samite/minirail cannot do.
Thanks chaps - using 25mm2 cable here so prefer to go straight in from the bottom and straight out the top to the MPPT. I just wasnât sure if polarity independent meant you could always attach load to the top OR bottom (I get polarity independent definitely means the pole order does not matter).
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Yeah, reminds of that TTT guy ⌠red in on right at bottom, donât take it out left top ⌠no, just donât get that confused with âpolarity independentâ.
Joke is, a well respected installer, made same mistake due to the + and - indicators on the No-Arks we have.
In from top from array, out the bottom to the MPPT, the 25mm2 cables?
Makes sense and anyone working there can see that is the case, I think.
A picture is worth a thousand words⌠Not that it matters for this discussion but the battery cables will connect to the left of the Lynx (not the right as in picture). PV cables come in where the battery cables are right now.
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regarding DC breakers polarity, i found this document. Just not sure if it applies to all brands but it does make sense
DC wiring_white paper_Altech DC series_0813.pdf (375.7 KB)
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Still a bit confused by this. With my non-polarised breaker is this wired up correctly? Solar enters bottom and exits top to MPPT PV. I ask cause I know the polarised MCCBâs you have to swap the + and - on the one end.
