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

literatos 22350 31
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Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
  • #1 18192737
    literatos
    Level 8  
    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 wrong fuse. It sowed a seed of doubt in me so I decided to ask in the forum. In the photo, the PV cable goes "from the top."


    Connecting Inverter to AC Box: Proper Fuse for Photovoltaic Installation
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  • #2 18192765
    kosmos99
    Level 38  
    The picture cannot be enlarged.
    The protection is three-phase and so is the inverter?
  • #3 18192774
    literatos
    Level 8  
    I added the picture again. Maybe now it will grow without a problem. The protection is three-phase and the inverter is three-phase
  • #4 18192824
    kosmos99
    Level 38  
    Did he say something more?
    Protection of what value, inverter of what power?
  • #5 18193074
    literatos
    Level 8  
    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)

    Connecting Inverter to AC Box: Proper Fuse for Photovoltaic Installation
  • #6 18193112
    kosmos99
    Level 38  
    The value of the fuse to which this cable from the PV installation is connected is not visible in the first photo.
  • #7 18193120
    edziu
    Level 29  
    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
  • #8 18193144
    3301
    Level 34  
    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
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  • #9 18193164
    edziu
    Level 29  
    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
  • #10 18193177
    literatos
    Level 8  
    kosmos99 wrote:
    The value of the fuse to which this cable from the PV installation is connected is not visible in the first photo.

    The fuse is 3-phase 16A. An induction and an oven are connected to it

    Added after 9 [minutes]:

    edziu wrote:
    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 a residual current circuit breaker, we will ask for photos of other cameras at inverters with open boxes


    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

    Connecting Inverter to AC Box: Proper Fuse for Photovoltaic Installation
  • #11 18193258
    Wlodek22
    Level 31  
    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.
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  • #12 18193709
    edziu
    Level 29  
    There is no protection for the DC panels
    in case of a short circuit on the DC PV line, a fire will probably result
  • #13 18193717
    kosmos99
    Level 38  
    edziu wrote:
    in the event of a short circuit on the DC PV line, a fire will probably result

    Buddy, see what the short-circuit and working currents of the panels are.
  • #14 18193735
    literatos
    Level 8  
    kosmos99 wrote:
    edziu wrote:
    in the event of a short circuit on the DC PV line, a fire will probably result

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


    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.
  • #15 18193751
    edziu
    Level 29  
    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.
  • #16 18193772
    literatos
    Level 8  
    edziu wrote:
    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.


    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.
  • #17 18194126
    Janusz_kk
    Level 39  
    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.
  • #18 18194140
    edziu
    Level 29  
    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.
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  • #19 18194301
    3301
    Level 34  
    literatos wrote:
    edziu wrote:
    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.


    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.


    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
  • #20 18194397
    Wlodek22
    Level 31  
    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.
  • #21 18194407
    theo33
    Level 27  
    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
  • #22 18194410
    Wlodek22
    Level 31  
    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.
  • #23 18194432
    theo33
    Level 27  
    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
  • #24 18194534
    Wlodek22
    Level 31  
    Arc in a fusible link filled with quartz sand?
    Well, unless you mean automatic to DC, because I'm fusible.
  • #25 18194554
    Janusz_kk
    Level 39  
    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.
  • #26 18194572
    kosmos99
    Level 38  
    I would not install devices with such powers under a wooden roof.
  • #27 18194664
    Pivko76
    Level 9  
    And I only have such security at my place. The board has a power supply connected to a differential under a three-pole fuse. Connecting Inverter to AC Box: Proper Fuse for Photovoltaic Installation
  • #28 18194705
    Wlodek22
    Level 31  
    And for that, they still wish for PLN 250 annual inspections?
  • #29 18194732
    Janusz_kk
    Level 39  
    kosmos99 wrote:
    I would not install devices with such powers under a wooden roof.

    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.
  • #30 18194743
    Pivko76
    Level 9  
    Wlodek22 wrote:
    And for that, they still wish for PLN 250 annual inspections?

    Who?

Topic summary

The discussion revolves around the proper fuse connection for a photovoltaic (PV) installation. The user questions whether their PV system is connected to the correct fuse after an electrician raised concerns. The inverter is identified as a three-phase unit with a power rating of 4.4 kW, connected to a 16A three-phase fuse. Participants discuss the implications of incorrect fuse ratings, grounding issues, and the absence of DC protection, which could lead to dangerous situations such as short circuits or fires. The need for compliance with electrical regulations and the potential risks associated with improper installations are emphasized. The conversation also touches on the importance of surge protective devices (SPDs) and the necessity of proper grounding to ensure safety.
Summary generated by the language model.
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