admiral

Response from CoCT SSEG department via email - they are remarkably responsive! The AMI meter requirement comes from the fact that you are on a commercial tariff, therefore section B, clause 2.3 of the Requirements document applies. We don't want to feed back, and installations in a sectional title complex are not any different from any other residential installation. This will punish home owners in any kind of group development for wanting to become more green, and to become less dependent on Eskom. By the way, here is section 2.3 of the requirements document:

Yeah - I will see if I can get to discuss this with someone in person, rather. I see this bidirectional AMI meter is insanely expensive - something like R15000. We have three bulk meters - do we change all three for one unit out of forty nine wanting to use a grid tied PV system without feedback? That makes zero sense. I can understand this if you're a commercial customer, with a bulk meter, wanting to install a megawatt of PV. But not for what we want to do. <sigh>

We have three meters... plus they'll want to change our electricity tariff too. Makes no sense if one owner wants to use solar power to affect 48 other units. They'll have to come up with better policies for sectional title / complexes than this.

At least I am the chairperson of the trustees so the politics is not that big an issue. Off-grid is an option - but I was not planning on having that many batteries as the system is intended as a house UPS, with *some* power saving with a few panels (and also some security from longer term outages). I just need to figure out why they want to have a new meter installed - not planning to feed electricity back into the grid at all.

@The Bulldog - does the above make any sense to you?

To speculate more; perhaps it has to do with section 2.4 "Tariffs" from this document: http://resource.capetown.gov.za/documentcentre/Documents/Procedures, guidelines and regulations/Requiremenst for Samll-Scale Embedded Generation.pdf I quote: "Tariffs are determined annually by the City and are subject to approval by NERSA. SSEG applicants should check the City’s website for the latest tariffs - the applicable tariff is the commercial and industrial small-scale embedded generation tariff and can be found on the City’s website. Customers on tariffs which have a daily service charge will see no difference to the tariff other than the addition of a generation credit component which is simply a rate/kWh exported. Note that commercial customers with a prepayment meter on the SPU 2 tariff will be changed to SPU 1 tariff and will require a bi-directional AMI credit meter unless their supply connection does not exceed 100A and they install reverse power flow blocking protection." I see on the complex electricity account there is mention of us being on "Commercial (Small Power User High)", although this is clearly a residential development.

I will call them tomorrow - the bit that is interesting to me is the "As your supply is more than 100A you would need to install a bidirectional AMI meter". Not sure what that means? Also, one unit out of 49 units installing solar power generation can certainly not make *everyone* else go onto a different electricity tariff. That is just daft. I fear I may have fallen into a technical crack here.

I got the following response from the City of Cape Town; I have not yet responded, nor do I understand the impact of this: Your setup qualifies for group SSEG, as you are bulk supplied. You need to apply via the usual SSEG process, in the name of the body corporate. Any subsequent applications would be treated as an upgrade on the initial application. As your supply is more than 100A you would need to install a bidirectional AMI meter. The City will provide and install the meter at your cost. The setup in our complex is this: there are three bulk meters delivering electricity from the City of Cape Town, and each unit has its own internal meter - read by the body corporate. I specifically said I do not want to feed back into the grid, so I do not understand the requirement for the bidirectional meter? Also - we have three meters... which one will be replaced?

Often the simpler a diagram, or piece of writing, the more effort went into it!

I used https://www.draw.io/ - it's a bit fiddly, but overall worked quite well. I was looking for something that makes the circuit easy to understand.

Please don't do learning from my circuit diagram (yet!) 🙂 I think I need some peer review on it still! I was hoping an esteemed member here would point at the diagram and tell me what was wrong. I still have to do the sneaky "See separate DC diagram" - will do that soon, and add it.

Yes, I just saw - the price has gone up ever so slightly 😮 I think I bought it for around R2500 in 2015.

This is what I have: https://www.hellermanntyton.co.za/products/digital-multimeters/tbm867/911-00013 No clamp function though, but it is safe to use. I did not realize how dangerous an unsafe multimeter can be if you use it on the wrong mode with e.g. 220v.

I have used https://www.draw.io/ - example:

At "least" the cabling between the garage sub db, and the house db, will only be for 220v AC - not the 48v DC!

Please be gentle 🙂 I had to start somewhere to explain to electrician what I required to be able to start using my new Victron Multiplus II. The garage is probably about 10 meter away from the existing db - and it is the only place where I can install the inverter and batteries. The existing cable to the garage is a paltry thin little thing - probably really only useful for the light and garage motor (it is a 15A breaker on the board at the moment). If at all possible I'd like to run a new plug point from the new cable that will be installed between the house and the garage - hopefully that is clear from the diagram.

Does it not need to be a "centre off" switch, e.g a Hager SFT240? The SFH225 is not centre off - although the SF263 is.

@SilverNodashi - may I quickly sidetrack here... I often see on electrical plans that the geyser / stove etc. are not behind the earth leakage, and on some other plans they are again. I wonder what the reason for that is?

And if I may interject here with a question of my own 😉 ET112 to be installed in main db one day - but venus device lives in garage about 15 meter away. What is the best way to connect? I looked at the suggested zigbee devices - but they are *not* cheap... Also - then I'd have to have a power supply close to the db etc.

Yeah I was also looking at this, and I am not sure how this has changed anything, really? I do want a changeover switch right there where the red block is so I can bypass the inverter completely - just a plain break-before-make thing like a Hager SFT240. Is that now a valid installation if I have a Hager SFT240 there, or not? And, if not, how is it different from running a UPS for part of your board - with a changeover switch right there? Or, is it a valid installation if I leave the red block out completely? In which case life will generally be great since the inverter just sits before the second db, and it only becomes an issue if the inverter dies - and I am not home to eh get the second db connected again.

Ok, perhaps I should have been clearer about *which* change-over switch I was referring to - this is the one on the output of the inverter, that has three positions: Essential loads connected to Eskom Disconnected from both Eskom and inverter Essential loads connected to inverter There will also be an isolator on the input side to the inverter - for disconnecting it from the grid. I am not sure how the change-over switch I referred to above can hurt you if someone switched it in the house? Just curious, really - I don't want it in the board in the house as there is no space left there.

I am curious if you may install the changeover switch in a sub db close to the inverter, or if it must be in the main db? The main db is old, and very restricted in space - just trying to see if I can save some money here... The question really is - what must be installed in the main db, and what can be moved into a sub db that is say in the garage?

Yes, a very expensive 😮 condenser dryer. Because I started complaining about stuff rusting in the garage.

I have measured the temperatures around the tumble dryer while it is running - Right next to the tumble dryer - as in millimeters away - the temperature is 36 degrees Celcius. 100mm away - the installation instructions from Victron - it is around 26 degrees Celcius. I'm pretty sure the inverter should be fine there. I'll install some isolation right next to the dryer, just in case. At least it will be nice and high in this position.

Ok, so it will be mounted at eye level, and then probably next to the tumble dryer. We don't use the tumble very often, and definitely won't be using it when the mains are down! I don't think therefore it will be such a big issue? I'll still add some insulation between the dryer and the inverter - at least it is a condenser dryer to it collects the water. In future, when I can feed back - for zero metering, not into the grid - then perhaps the tumble dryer will run when the inverter is running? The other option is to move cupboards around in my garage, but then the inverter ends up above the 8 AGM batteries - and that is also a no-no?