Installer Prices

By the sound of things I think you’re going to run into space issues in that DB. I’ve found that going for a two row DB board with the breakers in the top row and the fuses at the bottom works well.

Something like this:

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Just check you wiring of your Noark switch.

I have the same Switch.
The positive and negative is not the same on the input/output.
Top, - (left) and + (right),
Bottom, +(left) and -(Right)

I had the same problem. phone the supplier, and they told me the manufactures print it wrong. So just make sure about that.

What goes in on the top, must comes out at the bottom.

If im wrong, can someone please correct me.

Not sure if the Solis has that kind of protection build in.
I now know that the Victron MPPT have it build in!!!

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You are right. I use NoArk breakers too.

If both strings show 184V on the inverter I assume the breaker was wired correctly?

If you use the 35mm DIN-mount fuses: They are designed such that opening them makes it impossible to touch the top connections. So if you have your PV connected to the top of the fuse holder, it is physically impossible to touch the high voltage DC even if you open the fuse holder during the day time.

Noark is a good affordable breaker. If you want to be “windgat”, you can also use ABB DC breakers, but they are quite costly. On the AC side I don’t really use anything less than Hager breakers (about half the price of ABB, and just as good in my opinion).

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You are right, the way the wires goes in the top, it must exit at the bottom.

The part about the misprint is not correct to my knowledge. If the power comes from the bottom and the load is connected to the top, the + and minus turns around.

In short, connect your feed to any side of the breaker, but follow the + and - signs of the side you connect to.

EDIT: @karischoonbee the wires under the NoArk is connected wrong way around, I did not see it till @neliuszeeman mentioned it. Please ask your installer to swap them around before he switch the system on.

The way I understood it, for the Tripping device to work correctly you must follow the Polarity indication.

From their site:

This document
Discussion-Paper-Correct-Wiring-of-Double-Pole-DC-Breakers-LVL2-131210-v2.pdf (1.7 MB)
will explain everything better.

Sheesh, yes, good catch. If the MPPT does not have built-in protection there would have been sparks.

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How do you rate the Gewiss breakers that ACDC also sells? They are normally quite expensive, but ACDC regularly has them on special at almost 50% off.

Gewiss is good.

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very neat!

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So I have a problem then?

I just can’t see a reputable company making this error, or having made it not doing a product recall.
I’d be inclined to think these are counterfeit products.
In which case probably all bets are off regarding their functionality and rating capability.
I wouldn’t use them at all.

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These ones are single pole switches and only breaks the positive so I think this is fine as long as you have a battery connected.

Indeed yes have batteries connected.

I have no fuses between the MPPT and the panels, only these breakers which I installed solely for fault finding in terms being able to switch off each string individually.

Yes, unfortunately those are the wrong way around: The source should be at the bottom, and the load at the top. As it is the arc suppression will not work properly if the breaker is switched under load, which might cause damage.

Here is an excerpt from the manual:

With polarized breakers current must “flow in” at the plus and “flow out” at the minus.

I am no DC MCB expert. I use them a lot but I haven’t really paid them much heed compared to the big breakers I deal with.
That said, from basic principles:
Even load DC current will arc.
Arcs create heat.
Heat rises.
One could expect the MCB to be mechanically orientated to deal with this. Therefore the physical orientation could make quite a difference.

One method of DC arc extinguishing is to use magnetism to repel the arc to lengthen it to the point it breaks continuity.
Magnets can attract or repel depending on the direction of that DC current.
Therefore the orientation of that + & - can make a world of difference.

Now, a bit more specific, NOARK goes to pains to point out the current polarity on their DC MCB’s is to be respected. ( In other words, it won’t be a typo, the real NOARK would be paying attention).

They do offer a 1P + break MCB, but I can only see - break MCB’s available that are ganged with + break MCB’s. I cannot see a 1P - break stand-alone MCB in their product range offering.

An email to NOARK is warranted, at the very least.

The + and - on the breaker indicates the direction of current flow. If you work by the convention that current flows from the source (solar panel/battery) positive, through the circuit, back to the source negative, then your source positive terminal connects to the breaker + and your source negative to the -. Since the current flows in the opposite direction at the load side, the load positive connects to - terminal and the load negative to the +.

It would not have been so damn confusing if they rather used arrows instead of + and -: + = in arrow and - = out arrow.

You can use their single pole breakers for both your positive and negative wires, you just need to wire the input and output the correct way around in order to take heed of the polarity.

Yes, I know. Perhaps I should have been clearer.

Electrically Yes it would work.
But conventionally the live side of an MCB is at the top. I don’t know if that is a regulation in ZA, but it is certainly an observed convention. If you mess with things like that you are equally at risk of shocking someone.

Man, my OCD is going to kill me if I have to turn those breakers upside down so the + is on top.

I have isolation switches wired in between them and the batteries, but at those volts the arcing will just happen there now if I use them to first break the current.