TonyB

If they get physically damaged by hail or something and then, especially if they have water on them, the frame could have a high voltage on it and be dangerous.

@DMAC thanks for the feedback and keep us posted! Yes, I've been following a bit of Roland W except I play his videos at 150% speed 🙂.The TN-S picture I posted above comes from his YouTube channel. As mentioned above, only ground the frames of your PV panels and not the DC current (negative or positive) at all. And also don't connect any battery wires to earth. The frame is ok I suppose but I'm not sure how the inverter would handle it if there were a short?

I noticed the same thing. I think this is just a Typo. In another part of their web site it says 96.6: https://www.voltex.co.za/product/growatt-inverter-5kw-48v-spf5000-greenrich-lithium-battery-4-95kwh-96-6ah-51-2v-u-p5000/ Check with Voltex.

Hopefully you can monitor each strings performance going forward then and see what's up. Given that they are already in parallel, separating them may not show a massive improvement sadly. Because if one string becomes shaded it just becomes a resistor. The other string should still be operating fine. I suspect that your SW facing ones are the real problem (apart from it being winter), as @Scorp007 says.

Ah yes, I would separate them, one to each input.

@Savvoh Have a look at this topic, it may help? https://powerforum.co.za/topic/19328-optimal-solar-panel-wiring-configuration/ ie: Are your panels all in series? In which case you need to split them into a couple of parallel strings. A series panel in the shade will impair the whole string.

@Stu_D Bear in mind that by going parallel you will be reducing the voltage but increasing the amperage. You'll need to check your wiring, and your charge controller, to see if they can handle that. You may need to beef them up somewhat.

Yip, if some panels are in the shade they become a large resistor!

If your panels are in series in only one string then any panel that is in the shade will shut down the whole operation. You must wire your panels into a number of parallel strings for redundancy. eg: Have 3 separate strings, one string for morning, one for midday and one for afternoon - facing in the appropriate direction. With parallel strings it is important that you have a fuse on the +ve of each string.

Oh dear, sorry to hear that! If the panels are under load then things can happen if you just disconnect them. It's best to cover up the panels, or at least one in each series string first. Then you can isolate the panels and in theory your charge controller should be fine. Unless something else happened?

Here's a good video that shows the potential difference between a Live casing and the Ground (at 0V) because of the impedance going back to the supply Earth. In the event of a fault, and you are touching the case and the ground, this could cause a large current to flow through you, because of the large Voltage drop. This current would likely be insufficient to trip the breaker, but you would get a big shock. So, an RCD is definitely required. And, in order to reduce the Impedance back to the supply, and hence the large Voltage drop and current, a local Earth connected to Neutral would mitigate this and have minimal voltage drop, and thus minimal current flowing through you. The RCD would still pick up the imbalance between Live and Neutral as some of the return current is going back via the "real" Earth. Oh dear, I've just looked deeper into multi-earths. Utilities do this all the time, all the way down your street, but it IS a hazard. So, what's the solution? Relying on an RCD only? Go full TT (with RCD's) throughout without exporting the Earth? ie: The Inverter supply is TN-S but everything downstream is TT. ie: Local Earth not connected to Neutral. As in the picture below? Anyone have a better / safer solution? https://www.ecs.csun.edu/~bruno/MultiGroundedNeutralFinal_4-17-7.pdf And the Pro's and Con's of Single vs Multi: https://www.csemag.com/articles/grounding-points-single-or-multi/#:~:text=Single-point grounding means exactly,are grounded at multiple points. RCD Video and Potential Difference: https://www.youtube.com/watch?v=XN7s4ge1FoQ TT Installation:

ps: just further to your comment. The issue with a remote distribution point is about the potential difference in Voltages between the Earth and Neutral - as far as I understand, hence the need for a local grounding rod. I'll research some more and get back on this....

Thanks! As far as I can see the Neutral has minimal impedance so virtually all of the current will go back via there. If, however, there is a live short to Earth then some of that current will be absorbed by the "real" earth. (Me touching the Caravan). The RCD will see an imbalance in the Live and Neutral currents and trip. I can't see how a downstream earth could cause an imbalance between live and neutral?

Ok, I'm not sure I fully understand. The MEN system (in the image) has downstream connections. I would have thought that in any event the RCD would see an imbalance between Live and Neutral and trip? Other than selectivity issues and false tripping maybe from the downstream one? And if the upstream one trips on a downstream fault that's ok for now. As long as something trips 🙂 If I did feed any other outbuilding I would in any event take it from the main board, to another DB Board with MCB and RCD etc in the outbuilding.so hopefully this is not an issue.

Thanks a mill! Without the Grounding Rod at the Caravan the Voltage difference from a "live" fault on the Steel Frame to the real Earth could be massive, like 100V+, so it's only the RCD saving you really. If you also have a local Earth (rod) then the Potential difference is very small and you will only feel a buzz but not a shock. Thata's also why EV chargers can be dangerous... I see in Australia they use the MEN System. (Multiple Earthed Neutral) with Ground Rods at each outbuilding and the Neutral connected to Earth as well at each DB Board. In fact most utility companies do this all the time. (Mike Holt) ie: Grounding the Neutral at multiple points from the main sub station. This seems to be fine! See links and image.. One does have to be careful where you put the rods. Mine is rural off-grid so no issues but if you put the rod near your neighbour's water pipe and they have a fault it will come over to your place too! https://memberarea.necawa.asn.au/Admin/ViewContentPage?uniqueName=multiple-earthed-neutrals-men https://electricians-success-academy.com/learn/what-is-men-system

Thanks a mill. When you say "private", does that mean a direct connection to the rod from the panels with no other wires feeding off it? ie: As you say, to connect the system earth directly to the rod as well. I have another question: I may want to extend this to provide power to a (metal) caravan more than 30 metres away. This is outside the "equipotential" zone. ie: If there was a fault in the caravan and the metal became live and I was standing on the ground there, I could get a big shock... There would be a 30mA RCD there coming from a 100mA RCD in the main supply though. I understand that I could just put another grounding rod attached to the caravan and the caravan DB Board Earth Bar before the RCD too, to minimise the voltage difference between the earth under the caravan and the supply earth? Should I start another thread on this rather?

Hi, Thanks Sorry for the ongoing questions. Being an off-grid (TT) installation the only earthing available is via earth rods to be stuck into the ground. The inverter would be operating in TN-S mode though with the Earth connected to the Inverter and the PE earth bar before the RCD. (I'll add an MCB before the RCD and probably a Surge Protector in the DB board as well.) If the panel frames were connected to another separate earth rod nearby that would surely cause a problem, in the event of a fault or lightning strike, with the potential difference between the two, and the other rods picking up the fault? I assume the whole system needs to be grounded to the same earth rod(s). (Earth rod is bottom left in picture) Inverter setup:

Thanks for the feedback. Yes, I had meant the PV frames and not the energy carriers. I'm also planning an off-grid (TT) installation in a rural area. I'll be using an earthing rod. Maybe several connected together depending on resistance. The PV panels will be fused, with DC isolators and grounded Surge Protection Devices. I assume then that the panel frames and the SPD's and the system PE would all be connected to the same earth rods(s)? If the panels were hit by lightning would the whole system be sufficiently protected? Thanks.

Have you had any other feedback on this? I'm also a relative newbie but as I understand: 1. Many inverters already connect Neutral and Earth internally. You should test this with an Ohmmeter. If they are not connected then yes you need the Neutral Earth Bond to the ELCB in your diagram. You should only have one Earth/Neutral bond connection in your system. Either through the Invertor or in your DB board before the RCD/ELCB. You won't need the yellow link back to your inverter. https://www.victronenergy.com/media/pg/The_Wiring_Unlimited_book/en/ground,-earth-and-electrical-safety.html#UUID-7790f868-512d-9080-00fb-c272426e66c5 2. Victron recommend that your battery negative is also grounded. https://www.victronenergy.com/media/pg/The_Wiring_Unlimited_book/en/ground,-earth-and-electrical-safety.html#UUID-63a9c710-66e2-2c63-0d7c-d9345826267b. 3. Some people recommend not Earthing your panels: a. Because they are double insulated and it is not necessary, (unless they are at risk from hail damage etc.) and b. Because they may instead actually become a "target" for lightning! Perhaps have an independent lightning conductor higher than your panels if lightning is a risk. c. This is a complicated area and some might recommend that you still ground your panels as well. What is the experience of other people out there? d. Your SPD will need to be earthed though. 4. Being off-grid this is a so-called "TT" earthing system. Make sure your earth rod is more than 10m away from any other earthing systems or pipes etc. as any faults there may be picked up on your earth and fed into your system. 5. As always get an electrician in to check your installation out and to give you a Certificate of Compliance. May be needed for insurance purpose as well. They should also test that your earth rod is in spec. I hope this helps? If anyone has constructive advice on the above please assist. And be gentle please. 🙂 Regards