Elbow

You are welcome, have fun, don't electrocute yourself!

Hi @Roarty, I made my diagram using Lucid Charts and with a template file with electrical symbols. Those numbers were in the templates. So for me they don't mean anything. I think that sometimes the connections on the breakers are actually numbered though. I am no electrician so I wouldn't assume my diagram is properly done. But CoCT did accept it as some sort of outline design. Regards

Earth should remain connected with the main board main breaker off. But this sort of connection is very unsafe. They call a cable with a plug on both ends a "suicide cable" which tells you what you need to know. @Brendonvdh please get an electrician in to install a proper point where you can connect your generator and a proper changeover switch. Otherwise, buy some extension leads.

I will do that; And yes, my Infinisolar behaves the same - essentials output continues to be powered from panels and/or batteries in a power cut. I have lights and some plugs on that output. Meanwhile with grid present it runs grid-tied so the 3kVA size isn’t really an issue. So it’s a perfect solution.

It’s great news to hear that detectives are doing some detecting! Nice!

So I’m with you - grid tied FTW. If the stove wants 3.5kw and the panels can do 2 well the 2 comes from the panels. But we are all worried about Eskom and power cuts which pushes towards hybrid with some batteries. Since grid-tied shuts off when the power goes off as we well know at Black River Park which has an enormous PV system but is just as dark as anywhere else when the grid goes off. As you know the trick with hybrid for those in Cape Town is a design that satisfies the council. But as you know I’m trying to do this their way. So far it’s been an interesting process and I think my design is the better for it. But it’s still not clear whether I will need to do a two inverter setup - one for the PV and one for the UPS function. Still, it’s a process and i’m mostly having fun.

Well how about that. In quick succession I received a reference number and a "Permission to Install" letter. Based on the diagram and etc that I posted on page 1. So the game is afoot.

Hi, Mr Maimane may have some trouble understanding the complicated details you are pulling him into. Let's see what he replies. From my side I've had no response whatsoever to my application sent in on the 10th or to two followup emails. I just mailed my local councillor and maybe she will be able to find out the status.

Sounds like you're in Blighty. You'll get through it!

Hi, After some changing around in my house I have quite a few DIN breakers spare. Most are Major Tech. If you are busy with a renewable-related project and need breakers I'm happy to offer free to anyone who will collect at my house is Plumstead, Cape Town, or my office in Observatory. There's a 2P isolator, and 2P breakers at 40 and 63A, and a bunch of 1P breakers Drop me a private message if you are interested with what you need.

Well input breaker is 32A too. But of course any breaker will allow more than the rated breaking current for a time. So that was my plan. Block diagrams show the safety relay controlled by two detection signals coming from redundant control logic. I need to test to see what I find. If it is ordinary digital voltage level with a driver circuit to drive the relay coil I might be able to use it quite easily to switch a low power relay - with a 5v coil - and use that in turn to switch the contactor. I have a second unit which I can look at in the lab. No detailed design yet. I did write to Voltronic to ask about circuit diagrams (and also their advice about N/E bonding - we shall see what they reply (if they reply).

So I tossed and turned on Thursday night thinking about neutral - earth ties. My XYL asked me why I couldn’t sleep and I was embarrased to say why! I’m sure when I did she was thinking “who is this weird person I’m married to??” 🤣 I drew it all up in the 4 possible configs and thought about it and I see why you’d want the tie there when the inverter is isolated from the grid. And equally why you’d want it not there when the inverter is grid-tied. (This also starts to give me some insight into why CoCT might be cautious about hybrid inverters - they have a lot of different modes to think about). Anyway - I understand why I’d want to use a contactor to make the neutral earth tie but only when the inverter is isolated from the grid. Normally no current flows on the neutral to earth tie, right? But the whole point is that in fault conditions it will pass a lot of current so as to quickly trip the overload breaker. My inverter output has a 32A 2P breaker on it. So what rating would the contactor need to be? So now I’m looking for suggestions of an affordable DIN-mounting contactor. It only needs to have single pole switching. For me it would be easiest if the coil/solenoid was low voltage but I could switch that in turn with a low power relay. The working principle would be that when the inverter safety relay opens, isolating the inverter, the contactor would make the neutral to earth connection. Ideally I’ll find a signal from the inverter, failing that switching based on the AC input being present or not is pretty close. Thanks, Elbow

Demo regarding current flowing on the ground wire ...

So to think aloud - if I make a relay that can bridge N-E - how should the control logic go? 1) at the same time the safety relay opens the bridge relay should close. 2) or the bridge relay closes after a short delay? How short? 3) or the bridge relay closes before the safety relay opens?

I used this: its a Jean Muller KETO-00 - in my case with 80A fuses. its substantial and safe - you can pull the handle under load and the arcs are safely contained. Came from The Power Store. Pylon’s are I’m sure safer than lead acid since I assume the BMS will shut them off it you short them. But why take a chance since these batteries can push very many amps.

You can get all sorts of PV stuff from Rubicon on Montague Gardens.

I’m curious why you describe it as a TNC system since I don’t have a 2 wire live and neutral as per your diagram? Your diagram shows the live phases and a single PEN. All my plug circuits etc are protected by RCD whether on the grid side or the inverter out. So on my inverter out the neutral earth is tied before the RCD and so it would trip if "return" current gets around the RCD via me and earth. So I feel it’s safer than a floating neutral until I can get the relay worked out.

Hi @Jaws - i do understand that it’s a problem, but of course as things stand it’s a problem to link neutral and earth since that creates the multiple points issue when the inverter is tied, and it’s a problem to not have the link since neutral floats when the inverter is isolated. And floating neutral apparently creates a hazard (not too obvious to me why why since an RCD would still detect imbalance and trip if you touched the floating neutral and took current down to earth?) So I will see about a relay. In the meanwhile, which is the lesser of two evils?

My inverter is fed before the main board RCD. Which I think is usual.

Thanks, So my sparky tied neutral and earth on the output since in his view that was correct. and we tested both online and offline and no smoke was seen. But I will take your advice and look for a signal that I can use to switch a relay to connect the neutral to earth on the output only when the safety relay is open. One way would be to look in the data coming on the modbus data to tell me when the inverter has isolated its input.

Hi, I'm looking for the final view about tying neutral and earth on the output side of my Infini/Replus. When my inverter is online with grid and is grid tied then the output "sees" the tie on the supply side anyway. But when grid goes off the 2P "safety" relay opens and now the neutral on the output side floats. My sparky is here today and he says his course said that the output should have neutral/earth tied. When the inverter is grid-tied this seems harmless since on the input side there is an existing tie anyway. In offline mode the tie will tie the output neutral to earth which is a common earth with the supply side. I don't think it would be harmful in either mode but I am scared to damage my inverter with some unexpected issue? Thanks

That is cute, cheaper than the Carlo Gavazzi ET112 and with a display.

It’s his intention to do so. Sparky here on Thursday, I’ll get the panels hooked up this weekend or next and then I’ll report back if it works as advertised.

Don’t support all the policies of the ACDP and I think they could broaden their support if some such as support for capital punishment were dropped. Yes, the Old Testament law and all that, but Christians live in the new covenant and South African Christians live in South Africa with its history of wholesale use of the gallows. So I worry that their support for capitals punishment reflects a certain attitude to our history. However, I know Steve Swart personally and I see his commitment, hard work and his influence across parliament. I also see that he definitely does not have a "certain attitude to the past". So my vote goes to him. Which is exactly what you are saying, @plonkster

Hi, I think most people put the Tasmota firmware on them. I certainly did that. They then communicate using MQTT. You can install an MQTT broker (mosquitto) and now you can talk to all your switches easily from python, or using NodeRed, or other automation platforms. The mqtt config in Tasmota gives it a name so it doesn’t really matter what IP it has. The Sonoff is not of the highest quality so I wouldn’t switch heavy loads with it. Have fun.