Multiplus and CoCT

Had someone reach out to me regarding assistance with registering a Multiplus, not the Multiplus II, which was installed about 3 years, the Multiplus is not on the list, should he even try to register it, or will that open up a larger can of worms.
The installer was a friend from Jo’brg, who did not have any knowledge of CoCT regulations

Give more info of the setup. You can reg it as a Standby SSEG.

It is not CoCT regulations. :man_facepalming:

This installer friend in Jhb, it is better he gets the latest regulations book … it is all in there.

How do I know this, yonks ago when I had to register, the sparkie had just go his latest regulations book, and in there, all the info he needed for SSEG installations.

Cpt just made it easier for everyone, the same regulations that apply to all installs nationally, same as with DB’s and all other electrical installations.

The fact that a Munic does not enforce the SSEG regulations, is the resultant “confusion” that it is CoCT “rules”.

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It depends on whether the Multiplus is the device doing the converting. If the Multiplus is just a battery (aka backup) inverter, and you use some other tech (such as a Solis or Fronius PV inverter) to harvest the solar energy, then the Multiplus does not need sign-off. It must merely comply with the relevant SANS stuff for a UPS, which it does.

it was being was being used in a solar setup, but the owner found the approval to commission letter, which he found in a stack of paperwork and did not know that it had been done
So, a Multiplus was approved for sseg

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I was going through the SSEG Assessment control sheet provided by the Saldanha Bay Muni. They have the following section:

The more info tab seems to contradict this:

I think @TheTerribleTriplet aslo mentioned this about CoCT in one of his discussions.

I tried that last year and the application was rejected. The exact wording of CoCT’s reply was “A Victron inverter cannot be used as a UPS. This is a Hybrid grid tied system.” I eventually registered the MP2 + SmartSolar system successfully as a “Hybrid grid-tied SSEG”.

Do you know of anyone that has taken this angle and succeeded in getting it past CoCT?

I tried my best to convince them that the SmartSolar was merely a battery charger and the MP2 plays the role of a UPS, but no dice.

@plonkster and I discussed this recently.
I noted that despite the myriad of interpretations of the regulations, it was only the inverter that was performing as the grid interface isolation point that needed NRS approval.
(Inverters have been functionally capable of grid isolation for years already. An additional, more stringent requirement of double isolation through active and passive means is why approval is now conferred upon the chosen few at the grid interface).
My logic is that you are not relying on internal downstream inverters as a point of grid isolation. As long as they meet other typical SANS regulatory standards, they should not have to meet the more stringent grid interface requirements. ( As it is not their function).
This clause seems to confirm that there is still common sense out there. I interpret this that they are singling out the inverter that is “parallel to the EG” and noting it as the isolation point device and differentiating it from inboard inverters that are “behind” this inverter.
Common sense has prevailed.

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One guy here in Somerset West. I think he’s an old airplane designer. Used to live down the street from where I live now. He installed Solis inverters I believe. Can’t remember his name.

I have heard that there are inconsistencies in what is approved and what not. Perhaps he was lucky, or alternatively I was unlucky.

When the guy from CoCT shot me down and said that a Victron inverter “cannot be used as a UPS” I was disappointed that my plan was foiled, but I wasn’t surprised.

To me it seems reasonable that a grid-tied inverter should have NRS approval if it is the first inverter at the interface to the grid, regardless of where the energy comes from that it stores in its batteries.

You can use a MultiPlus as a UPS, which means forsaking ESS completely.

No-one does that though, and it’s trivial to change from UPS mode to ESS mode, so I understand why they’re taking a hard line here. The system is just too easily reconfigurable. Even if you weren’t using ESS, and they approved it, you could just change it tomorrow.

So I think since the equipment can operate in this way, it needs the certifications.

If you approve as Off-Grid, that’s more than a config setting since you need to wire it up and a physical connection where your approval didn’t have one is obviously a problem.

Long and the short of it is that Victron needs to get it’s act together with the MultiPlus II certifications, because currently very few of their models are actually approved for on-grid use in SA, regardless of how much we like them. They can’t keep wringing their hands and say “Well actually, you bought an off-grid inverter.”


Did you mean the Multiplus, without the II (2)?

The Multiplus, going way back when I had to register, was not NRS-approved due to hardware, hence the Ziehl being on the list to solve the issue. Unfortunately, it did not work out like that, Ziehl was a useless addition to the NRS-approved list.

Adding the Ziehl does render it compliant (by which I mean, it will very likely pass all the tests just fine)… BUT… it can only be approved if that combination was tested to confirm specifically with NRS097. It was tested for VDE-AR-N-4105 (Germany), so in those countries you can happily run that hardware with the Ziehl anti-islanding switch. But it was never tested for NRS097.

The combination was however tested with a particular model of Hoymiles micro-inverter, so those inverters can use a Ziehl to be compliant. Of course, this adds to much cost that I don’t think anybody does it anyway. So the Ziehl is indeed somewhat useless on the Cape Town list.

Talking to one of the COCT guys that came to inspect a site I am working at, told me that they are worried about the uptake in power requirement, when the whole neighborhood’s inverters start charging their batteries at the same time and one of the ideas floating around their office is to make clients use a circuit braker on the input of the inverter limited to 15% of the main breaker, they are not satisfied with a software charge limit onli

Nope. The original will never have it, but the II works – we know this, but they don’t have the certification to prove it. Only for the 3 & 5 KVA and not even sure all of the models.

That makes a lot of sense for UPSes as they’re generally used, but not for grid-tied.

I mean, sure, the city is worried, but it negates the entire purpose of a whole-home backup.

What would make sense would be a 15% breaker in parallel with a ripple relay. Then you can start charging with 15% and they can ramp up to 100% in sections.

You would need to tell your inverter to draw less initially in some way. The Fronius PV inverters support this directly with digital inputs, but obviously only for the other direction.

It should not be hard to monitor this. The NRS097 regulation says wait 60 seconds, and if everything remains in spec, you can close the relay (after which such inverters will start charging immediately). So the load that shows up more or less exactly a minute after you restore the power… that’s the compliant bunch. You can see them on a chart.

Of course UPSes don’t need NRS097 certification and will start charging immediately. These will be indistinguishable from all the geysers and other appliances that turn on immediately when the power returns.

True, never thought of that, I shall point it out to my CoCT sseg contact, regarding, geysers, etc

That would also limit passthrough to 15%, wouldn’t it?


Precisely, which is why it will never fly (or at least, will face a litany of complaints). It will basically kill whole-house-backup. 15% is a 10A breaker, for most single phase 60A people.