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Circumventing the COCT 3.5kVA limit

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5 minutes ago, Tariq said:

I was under the impression that according to CoCT, off grid means that the inverter cannot in anyway be connected to any part of your household electrical circuit that is also connected to the grid 

There's plenty of confusion around this topic, and perhaps at some stage even in the ranks of CoCT. However, if you look at the CoCT SSEG webpage you will note that there's only two models: Grid-tied and off-grid.

"Grid-tied" is a standard term used to indicate that the inverter synchronises with the utility grid and is capable of injecting power back onto it. Everything else is off-grid. If you look at the declaration form for off-grid systems you will note that there are several options listed:

• Passive standby UPS utilised as off-grid hybrid SSEG

• SSEG alternative supply in terms of SANS 10142-1: 2017 - The wiring of premises 

• Electrically separated off-grid SSEG installations that is not interlocked with the utility electricity grid as a switched alternative

Note that only the last option is "electrically separated".

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  • If one has extra space in the DB, one can install an extra changeover switch so that the non-essential loads can be switched over to the Inverter Output.  You must then carefully manage the loads so t

  • Exactly. The AC-input limit that Multis and Quattros have for the last decade or so, mostly used by people in boats and yachts who have limited shore supplies. You can use that for this purpose.

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So a person could hook up, let’s say to the input of an Axpert with pv to the household grid supply and feed the output via a changeover switch to their db and register it as off grid  ??

  • Author
5 minutes ago, Tariq said:

So a person could hook up, let’s say to the input of an Axpert with pv to the household grid supply and feed the output via a changeover switch to their db and register it as off grid  ??

Yes, that would be a "Passive standby UPS utilised as off-grid hybrid SSEG".

This makes the wiring less of a chore since you don't have to split out a new DB for your essential loads, but it does leave your heavy loads (e.g. oven and geyser) on the output of the inverter. Consequently you may need to shell out for two or more units in parallel.

2 hours ago, Tariq said:

I was under the impression that according to CoCT, off grid means that the inverter cannot in anyway be connected to any part of your household electrical circuit that is also connected to the grid 

This was my impression as well. If you want to connect AC in to the Axpert you need to disconnect the PV, or if you want to connect PV you need to disconnect AC in.

I have a 4.6kW grid tied Solis inverter and a nominal 3640W of PV. How would I "prove" that for all intents and purposes my system will never exceed 3.5kW? Panels are North facing, on a 40 degree pitched roof.

17 hours ago, PierreJ said:

Axpert inverters are not grid-tied, so the approved inverter list does not apply. Your install is classified as a "Passive standby UPS utilised as off-grid hybrid SSEG".

You don't need an engineer to sign off on the system, but you will need an electrical CoC, and if there is a changeover switch then you'll need to attach a test report for that. The form you need to fill out and the related info is available here:

https://www.capetown.gov.za/City-Connect/Apply/Municipal-services/Electricity/apply-for-authorisation-to-install-a-small-scale-embedded-generation-system

You are allowed a maximum battery charging current equal to 25% of your main breaker (i.e. 15A AC), but I don't believe a breaker is required for that if you can limit it in software. Because your solar is "off-grid" it doesn't really matter how many panels you have.

 

Thats great new, thank you.

Fortunately, we don't pull more than 60A 48v DC / 13A 220v AC when charging from grid. Limited by software and hardware

  • 4 months later...

Been a lurker for a long time but herewith my first post.

I am planning a very similar system to @PierreJ but I have a 3 phase 60A mains supply. My plan is to maximize self consumption

Current design is

  • 22 X Canadian Solar 450W mono panels,
  • 2 X Victron Smartsolar MPPT
  • 3 X Multiplus II 3000
  • 5 X Pylontech 4.8Kw UP5000

Only the pool pump and one garage with two deep freezers will be on non essential. The rest will all be essential loads.

Does anybody know if this will pass the COCT requirements? 

Thanks in advance

 

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