Warning, danger. The markings on this DC breaker series from Noarc are wrong. The red arrow shows clearly the markings and flow that are Correct. The markings in the blue circle are clearly wrong. DO NOT WIRE ACCORDING THE + - SIGNS. You will create a dead short!
 

Aren’t you supposed to wire polarised circuit breakers according to this document? Or is it different for Noark?

Discussion-Paper-Correct-Wiring-of-Double-Pole-DC-Breakers-LVL2-131210-v2.pdf

That document is correct indeed. That said however, on the 4 pole breakers as I used, they are internally bridged at the bottom and that is where the issue arise.  When looking at the pictogram printed on the front (pictogram is correct) you will see that the + and - indications at the terminals are completely wrong. Top left terminal (1 in the connector convention) are wired to terminal 3 next to it on top.

5 hours ago, Sarel said:

The markings on this DC breaker series from Noarc are wrong.

I don't think so. This series has apparently only 250 VDC rating per unit, so all 4 units need to be in series to achieve the 1000 VDC rating written on the front. That's a little misleading, I'll agree.

So this 4-way block is intended to be wired in series. In fact, it's not intended that any wires are connected at the bottom. It's not visible in the photo what is going on there.

From the installation manual:

Note how the bottom terminals are whited out.

It appears to me that you are trying to use these to combine two strings of panels in parallel, is that right? Four PV inputs at the top, one pair at the bottom leading to the inverter? I can't see how this can be done with this device.

If however it's just a 2 pole 1000 VDC isolator, then that's fine. You could wire it as per the right side of the above diagram, with the +3 terminal going to the negative side of the inverter, and the -5 terminal going to the positive side of the inverter. The load side always has the "wrong" polarity. If that's what you're trying to do, and the big red box is lightning protection on the panel side, then I think you have the 5 and 7 terminals swapped, so these breakers won't be operating correctly (the magnetic blowouts will make things worse rather than better). But I can't be certain where the wires are going.

A better picture. And the markings are still incorrect. Here you can see there are no cables connected to the bottom.

Surge protector is to the right, the red Device and the panels connect directly to it. The thin black arrows point to panel string wires. From there a + jumper to the input + arrow in red, also from sp negative panel a - jumper to the far left indicated by a black arrow pointing to the - symbol. The black arrow pointing to the + symbol is the negative output when switched on and the red arrow pointing to the - symbol is now the positive output. Verified with a meter, confirming the pictogram is correct. So it’s wired according to the right hand drawing of picture you attached.

The - and + signs on the front of the device is still incorrect, well the middle two on poles 3 and 5 that is.

Edited September 11, 20214 yr by Sarel
Spelling and added clarification about what is wrong.

In the first picture the load was not connected to the middle two poles (3 and 5) but that was corrected after the first picture was taken. The panels feed to poles 1 and 7 and the load is attached to poles 3 and 5.

Edited September 11, 20214 yr by Sarel
Spelling

14 minutes ago, Sarel said:

The - and + signs on the front of the device is still incorrect.

Sorry, no. These symbols are for IF the SOURCE is connected to them. They will be exactly wrong for the load. That's how those symbols are supposed to work, and it's all explained in the PDF linked to by PowerUser.

I note that you appear to have swapped terminals 5 and 7 between the first and second photos; in the last photo, you have the polarity correct.

Think of the breaker as a small-value resistor. So there will be a voltage drop across it. The voltage drop will have the polarity as given by the symbols. The positive input to the inverter will have a slightly more negative voltage than the positive end of the panel string, so it gets a minus sign even though it's way more positive than the other end of the inverter.

This confusion is why some jurisdictions have banned polarised breakers.

The symbols are what is confusing, they indicate polarity on the input (source) side but flow direction ( relative to input) on the output side. Still idiotic, glad they getting banned. Bad UI design by any stretch of the imagination. If you have to explain it….

Edited September 11, 20214 yr by Sarel

14 hours ago, Sarel said:

Bad UI design by any stretch of the imagination.

Yes, I think they would have done better with an arrow and a plus sign near the middle of the arrow. That surely suggests conventional (positive to negative) current flow.