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Inverter Grounding ?

  • 24-01-2020 9:38pm
    #1
    photosmart
    Registered Users Posts: 308 ✭✭


    Hi All


    Looking at installing a small off grid type system and have my eye on a couple of different inverters.


    After looking at youtube etc for most of the inverters none of the videos mention "earthing" or "grounding" - they just seem to plug in the positive and negative wires from the charge controller into the inverter and away they go.


    I was looking at a victron multi inverter 1600 and the manual has a section talking about grounding. Anybody any insight into this? Does this mean this inverter needs a big palaver and linking to a grounding rod etc or is it something simpler?


    Any advice appreciated


    P


Comments

  • #2
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    You need two grounding(s).

    One, for the PV panels itself, mostly used in places where are thunders common presence.Good for antistatic protection as well.

    Then,the inverter should have one as standard through the earth' third wire in the cable, on the AC side.

    The inverter has also measurement of the cable ISO resistance and if something wrong it refuses to couple the PV panels to DC inputs until the short/leak/open circuit issues are resolved. At least that what my ABB is doing through the POST (PowerOnSelfTest).

    https://www.youtube.com/watch?v=sh5sEYPwSnc


  • #3
    photosmart
    Registered Users Posts: 308 ✭✭photosmart


    Thanks for reply but I think you are basing this on a grid tie system whereas I'm setting this up as a standalone. Ie just solar panels charge controller batteries and non grid connections inverter.


    Or is it same?


  • #4
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    photosmart wrote: »
    Thanks for reply but I think you are basing this on a grid tie system whereas I'm setting this up as a standalone. Ie just solar panels charge controller batteries and non grid connections inverter.


    Or is it same?

    A proper designed and engineered house should have a earth link connection,
    connected up in the fuse panel.
    Thats where your PVs "earth" connects too.

    I'm not a spark but i read about building off grid houses and part of the foundation is geting the right Ohms-age for the ground / earth rods link, deep in the ground. Check with the architect / structural engineer adn make sure you call a spark to measure before sealing it.

    More important it will be to "isolate" the batteries away from the main living areas.Make sure proper ventilation and structure is build to accomodate the system.Also,monitoring and alerting system in place based on the type of cells and the charging/dischardcing/floating parameters.

    What type of batteries are you going for ?
    @Unkel here has almost a year since is trying to get his shed completed for some heavy duty UPS batteries,he may have more info on that.


  • #5
    photosmart
    Registered Users Posts: 308 ✭✭photosmart


    Thanks for reply - I'm actually putting this system on my shed which already has AC power but I'm doing it as a backup / hobby install as I want to run a small system and learn etc...


    I've been reading up since and I think I can just connect the chassis ground
    to the ground part of a normal plug () which will allow me access the shed /existing ground but I'm going to check this with an electrician first.


    The americans seem to hammer in a grounding rod and connect to that for full off grid systems and I could do that but I don't see much mention of that process here in Ireland so I'm assuming the installers just connect to some existing ground.


  • #6
    [Deleted User]
    Posts: 5,238 ✭✭✭[Deleted User]


    A Ground is a 0V reference connected to a chassis from a Negative. More commonly associated with Direct Current installations, unless you're 'murican and callit whatever ya want.

    An Earth is a planet reference connected to a phase leg. This connection makes the connected leg a neutral. Exclusively used in reference to alternating current distribution. While installations containing DC components are best practice earthed, they wouldn't be in the abscence of alternating current {citation needed}.

    The more things we connect to planet voltage the more likely we are birds on a wire where the wire is the planet. Or rather the wire we are on is referenced to the planet ie. equipotential.

    By tying our generators to the planet as well as neutral and conductive loads the Earth and Neutral become the compatible routes to electric flow within the system. One of them may conduct and one may not. By using circuit breakers to interrupt supply when the one that may not conduct does, we reduce risk to all involved.

    You can treat a lottov inverters as you would a regular genset for the purposes of earthing.
    I'd say RTFM except Victron are very light on info when they're in danger of making something look too complicated to be bothered with.
    Studer write a not terrible manual for their inverters...


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  • #7
    [Deleted User]
    Posts: 5,238 ✭✭✭[Deleted User]


    Link #1

    Link #2


  • #8
    photosmart
    Registered Users Posts: 308 ✭✭photosmart


    Thanks Dude but you lost me there. It's not a marine system and I'm just wondering if there's a simple fix that non electrician can do.


    This seems to be a simple question but any answers I've found seem quite complex.


    There is a chassis ground point on the inverter and it's a case of running a wire from that to some grounding point but I'm not sure what's the simplest clearest solution.


    Cheers anyway


    P


  • #9
    [Deleted User]
    Posts: 5,238 ✭✭✭[Deleted User]


    It's a complicated matter. It depends on your installation. So no simple answer...
    It doesn't especially matter that it's not a boat, other than galvanic corrosion the setups are similar. There's not many markets it applies to.

    It's not about simple fixes it's about best practice.
    Sir Liamalot wrote: »
    You can treat a lottov inverters as you would a regular genset for the purposes of earthing.


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