Connecting Inverter to AC Box: Proper Fuse for Photovoltaic Installation

Question

Hello, I have a short question for more electricians than I am. Some time ago I became the owner of a photovoltaic installation. On Saturday, an electrician was at my place (for a completely different reason than PV) and he told me that the PV installation according to him was connected to the...

kosmos99 · Answer

The picture cannot be enlarged. The protection is three-phase and so is the inverter?

literatos · Answer

I added the picture again. Maybe now it will grow without a problem. The protection is three-phase and the inverter is three-phase

kosmos99 · Answer

Did he say something more? Protection of what value, inverter of what power?

literatos · Answer

An inverter with a power of 4.4, and regarding the protection on the AC side, I am throwing the next picture It will be much easier (based on my news)

kosmos99 · Answer

The value of the fuse to which this cable from the PV installation is connected is not visible in the first photo.

edziu · Answer

Does your RCD breakout? are the inverter and PV system grounded? I see that the cable from the inverter is 4x4mm2 the yellow-green wire with the blue PEN ending is connected correctly as long as it is a PEN while L1 L2 L3 is connected to the residual current device we will ask for photos of the other cameras at inverters with open boxes

3301 · Answer

You can see that the inverter circuit has been connected to the triple B16 together with another circuit, probably some gn. 3-phase or an electric kitchen due to lack of space (there are only two free), while the inverter protection in this new switchgear is C16, and at 4,4kW 10 would be enough and it doesn't make sense because earlier B and finally C Added after 3 [minutes]: Two green-green PV cable a bit interesting? and I don't see blue

edziu · Answer

probably the second yellow-green is PE and the yellow-green with a blue shirt is N if it is, it is a wrong connection because it is connected to PEN and not to N

literatos · Answer

The fuse is 3-phase 16A. An induction and an oven are connected to it Added after 9 [minutes]: The differential does not strike, but the installer said that if it strikes, then the inverter will flow to another place. Yellow-green with a blue patch is probably N (if there are 4 wires, one must go N), while the other yellow-green is a separate wire next to the main one, so it is rather an earth electrode. There is only one box under the inverter on the AC side, the photo of which is above, and on the DC side there is another box, the photo of which is below

Wlodek22 · Answer

I am not an electrician, but for my peasant reason, as a PV inverter is connected to a differential to the meter, during the operation of the PV, when the current leakage occurs, the differential may not work.

edziu · Answer

There is no protection for the DC panels in case of a short circuit on the DC PV line, a fire will probably result

kosmos99 · Answer

Buddy, see what the short-circuit and working currents of the panels are.

literatos · Answer

The electrical data of the panels (according to STC) is a short-circuit current of 9.79 A, and the operating current (I hope that what is marked in the catalog as the maximum current at MPP point) is 9.22 A. Electrical data according to NOTC are about 2 A lower. If necessary, I can put in the catalog card of the panels.

edziu · Answer

I will not explain what are the effects of a short circuit on the PV instance the fact is that the installation is poorly made and inconsistent with the design and applicable regulations.

literatos · Answer

Of course, the effects of a short circuit do not need to be explained to me Can you develop the issue of non-compliance with the regulations because these are the regulations I was looking for about the protections required in PV installations and I could not find. I must have some support in talking to the contractor.

Janusz_kk · Answer

In my opinion, there are no fuses between the PV and the PV protection, which you showed in the 3rd picture, in the event of the protection being triggered, the panels will be short-circuited.

edziu · Answer

A attached documentation, diagram, etc. send the diagram, we will see if it is ok The current installation is dangerous, the RCD will not work if someone advises me, I will not write about the consequences, and the prosecutor will definitely find someone.

3301 · Answer

And in fact, you will not find that the DC protection must be (although it may be useful), it is impossible to select and protect one chain when the short-circuit current is comparable to the rated current of the panel, only when the chains work in parallel, such fuses make any sense, although what short-circuit , where? since these protections are not mounted on the panels but on the inverter. As for the AC, it should not be connected together with another circuit, as there is no space for three additional devices, it is either replace or add an additional switchboard or lay a wire that meets the requirements of earlier protection, in this case probably pre-meter, which is probably 25A, so a wire with a cross-section 6mm2 and connect after off. Main

Wlodek22 · Answer

The fuse is there to prevent a fire in the event of a strong overvoltage and an explosion of the SPD. It cannot save you from a direct hit by lightning, but when it hits an adjacent lightning rod, it can help the SPD survive.

theo33 · Answer

Is the SPD going to survive? what about the panels and the inverter, if there are several thousand V and the fuse, let's assume that in this case 12A will work

Wlodek22 · Answer

You ask the rhetorical question. People have to survive, and by the way, the house, SPD, inverter and panels are secondary issues. You're afraid, make a decent lightning conductor.

theo33 · Answer

SPD is designed to lower the voltage that can be induced in the event of a discharge by closing the circuit to the ground, when such a fuse works, the resulting arc and voltage flashes to further installation may cause a much greater threat

Wlodek22 · Answer

Arc in a fusible link filled with quartz sand? Well, unless you mean automatic to DC, because I'm fusible.

Janusz_kk · Answer

On DC, the fusible ones are probably the best anyway, because others can go up in smoke if the polarity is reversed and the roof burns down.

kosmos99 · Answer

I would not install devices with such powers under a wooden roof.

Pivko76 · Answer

And I only have such security at my place. The board has a power supply connected to a differential under a three-pole fuse.

Wlodek22 · Answer

And for that, they still wish for PLN 250 annual inspections?

Janusz_kk · Answer

But you have a sloping roof, wooden, because you hardly ever meet steel, there may be roofing different, and you have the fuse box and protection under the roof rather than on the roof. So the fire from the box will set fire to the wooden structure.

Pivko76 · Answer

Who?

[Solved] Connecting Inverter to AC Box: Proper Fuse for Photovoltaic Installation

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