Dadd111

I looked at it and I can't see a problem. I'm not an electrician, but tripping the ELB means you have more current going in on the one leg than is coming out on the other side and I don't see it.
You didn't say what inverter is used, but I have an idea. Earth and Neutral will be bonded on the Eskom supply side, before entering your make-before-break changeover switch (which throws all three phases in parallel I see). You aren't allowed to make your own bonds on the consumer side, usually. When you disconnect the grid, you also lose the earth/neutral bond and earth is now floating. You should add your own earth/neutral bond after the inverter but before the changeover switch, so that earth and neutral is also bonded while on the inverter, but both bonds are never active at the same time (that is against SANS).
It still doesn't make complete sense to me how that would cause an imbalance, but I don't see the inverter-side bond -- unless the inverter itself implements it -- and that might have something to do with it.
Not all inverters can be bonded in this manner, some can, and some do it out of the box.

Even if it is, which I suspect would come with lots of gotchas, I would split it. You can put a surface mount next to the existing one so that it is easy to pull the wires across. For example, this is what my sparky did for mine:

There was a time we debated Pure Sine Wave vs "modified" sine wave (which is really square wave), but that was always with the proviso that the sine wave one was two or three times more expensive. This is no longer the case, so the question is WHICH sine wave inverter. That too, is beaten to death twice a week. At the moment there is some sensitivity around the grid tie regulations, one of the popular inverters on this forum is currently somewhat in question.
I had the same idea in 2013. The only really modular system to this day is a micro-inverter system (small grid tied units under each panel), and I don't think any of those are legal either, and none of them have a limiting mechanism to avoid grid feed-in. Some models can be put in parallel, and that allows some modularity, but everyone's favourite (The Voltronic Axpert) starts with a 5kva model so you're already in the big leagues with just one unit. Batteries were never really extendable (not with lead acid), and now with LFP you still start with at least a 2kwh block that sets you back 15k.
I bought a small Victron Multiplus, with the idea of buying another one later and putting them in parallel. But that inverter turned out to be a hybrid and worked so well with the grid that I never did it.

Hi Antony,
if I remember correctly you have purchased a ES series Goodwe inverter. I have the same and found the wiring diagram in the manual very accurate and helpful. The only thing it does not show is the isolators and fuses on the DC side (Panel array and Batteries). As Plonkster advised you need both. For the panel array I have used Noark Ex9BP-N 10A  (isolator and fuse combined). Attached is my wiring diagram (not yet approved by the engineer)

I LOVE this video:
 

@BowsieThey do.
Din_Changeover_Onesto.pdf

Hi all,


 
I’d greatly appreciate an experience eye cast over the design and electrics of a Goodwe ES 5048 inverter setup I’m planning that includes solar and Pylontech batteries to make sure I’m not doing anything stupid.

 
Firstly, some key challenges and pertinent info:
The existing DB board is a cheapy, annoying single row job and is nearly full as it is. I am able to make some space for the Goodwe energy meter by removing a lights timer I have in the board, replacing it with a suitable day/night sensor instead. So I am limited by how many devices I can add to this board without adding a surface mount box which I’d like to avoid if possible. This is located in the garage. If necessary, I could move some load breakers, such as the geyser for example to the new surface mount DB by the inverter.
I am not totally decided as to the inverter location so some input here would be appreciated. The garage is not the most spacious around the edges and I don’t like the fact I have to put the Pylon’s on the floor where it’s likely to get in the way. Also as garages are, it gets a bit dusty and cob-webby over time, and as it has a metal door facing east, it gets pretty toasty in there in the mornings in summer. Maybe I’m being a bit OCD about this, but this doesn’t seem like the ideal place for the Pylon’s.
I have an alternate location in a fairly large built-in cupboard inside the house. The cupboard would be easy to amend with a vent and a quiet 10cm ceiling extractor to assist with airflow. It is however, about 25m away from the distribution board by the way of cable run.
To keep things simple I’d prefer to simply attach all the existing loads directly to the inverter output. I believe my energy consumption would allow for that (typically 200-230kWh/month, peak according to efergy meter has been 9kW once in the last 5 months). If I really ran into problems, I could move the stove/geyser from the inverter output.
I have 255V coming out of my wall sockets which is just a “feature” of my complex’s feed transformer. I believe the Goodwe can handle up to 270V.
 
Thus, based on the Goodwe manual and other research I have the following basic electrical layout in mind (see Word art below). I haven’t included details such as the fuses and other components on the solar/battery side. My main questions would be:

Is my plan sound? If I understand the specs in the Goodwe manual, which isn’t all that clear on the matter, it appears it can supply up to ~9.2kVA from mains as pass-through power if required. Not sure if inverter backup power can be added to this total if necessary. I understand that if power fails I’m limited to the Goodwe’s backup output of 4.6kW but I think that would be easy enough to self-manage around.
The wiring from the main DB to the inverter would require 16mm^2 cable in both directions if I am correct. Not cheap, but I’d rather put in the full size cable than down-rate the breakers.
How large does the earth wire need to be that runs between the DBs? Is putting the inverter in a cupboard a dumb idea or should I just leave it in the garage?