Simple answer is unfortunately no, as the two systems aren’t electrically disconnected. I asked the exact question when we had our own system installed and it was a clear no by those I asked. The network operator gave the not electricity disconnect reason.
The only way is to have two systems would be have one grid connected and a completely separate building (shed/workshop)/dwelling (second house or granny flat) on the same property off grid with a battery system. The battery system is (totally and always) electrically disconnected from the property meters. Getting an electrician to do this may also be an issue as state government electrical safety rules may also be a barrier.
Having a grid connected system and a separate off grid battery system on the same house circuitry currently isn’t possible, but this may change in the future. There are new systems which offer a similar setup, but these are a single install (approved under the Australian Electrical Safety Laws) rather than a mismatch of systems to achieve a similar outcome.
Sapphire have not been out to inspect the system. Due to initial difficulties contacting them and because I did not know the cause of my system not working, I got another solar electrician to inspect as I was worried about safety issues. They confirmed and showed me that the inverter had blown and used zip ties to ensure the system was closed up until warranty repairs could be done
The cost of that inspection by the other electrician can also be added to any claim you make through your Civil & Administrative Tribunal (CAT). If Sapphire delay too long (or don’t contact you or don’t fix the problem in a reasonable time) and you have contacted them in writing as per the ACL requirements giving them a reasonable period to contact and/or undertake the works, you can use another company/installer to do the repair and the cost can be claimed from Sapphire. As above I also advised contacting your house insurer and see if they will undertake getting the work done, if you have to pay an excess you can claim that from Sapphire via the CAT.
“It depends…” might be the way Dr Karl would answer the query.
What is it that you want to achieve? Assume the reply @phb received was very specific to one property and one distributor. The rules and approvals vary between distributor networks and state or territory. Hence there may be other and simpler solutions. All impose export and connected capacity limitations.
There are a number of different configurations and ways to upgrade (renew, add or expand) household PV systems, including battery backup. It’s possible to have 2 or more grid tie inverters configured on the same grid connection. IE two systems on a single phase supply. Protection against islanding is achievable.
Maintaining power using one, or more than one system on the same connection is also possible. Some models of hybrid inverter are more adaptable than others. Some such as a Tesla Powerwall are limited and only provide backup power on a dedicated circuit. Technical solutions for operation in various parallel or connected systems are available for most models of inverters. EG Manufacturers such as Victron and SMA/SunnyBoy provide a range of products and configurations. It’s a topic best discussed with an accredited CEC Designer.
One typical option is a manual or automatic backup switch and control unit installed at the meter. Common where there are several or more inverters in larger systems. Or you have an off-grid capable system connected to the grid. The options for doing so vary between manufacturers products and models.
EG
Edit - added one example of configuring a home PV system using a Victron product to provide the grid connection and backup power with an existing PV system.
For those still curious or wondering:
Consider that when the grid power goes down both your neighbours inverter and your inverter are both simultaneously connected to the grid, each other and also possibly exporting. They will both still shutdown/disconnect from the grid in response.
While Sapphire do not appear to list your inverter on their web resources, the inverter in your pic for general interest has a similar appearance and nominal 5kW output as,
Note the Sapphire Solar logo. How the two business and products relate is not self evident as the QueSolar home page appears to be in Dutch.
In respect of the current CEC approvals of inverters brands Sapphire, Gem and Que Solar all drew blanks. That’s not to say the product isn’t imported under a different manufacturers branding. Or it no longer appears on the list due to recent changes in approval requirements listed in the CEC web site.
I agree with is approach as well, but one would need to formally advise in writing to Sapphire Solar that this is the approach to be taken if a warranty repair is not done in a timely way.
Being around a 5kW system, it is a reasonable sized domestic system and if a high household solar electricity use of that generated, it could be costing about $3-4 day not to have the solar functioning. It is coming up to three months, which is possibly around $300 of lost benefit. A new reputable 5KW inverter start at around $2000+.
Consumer, Building & Occupational Services Tasmania, following some solar roof fires just posted again to solar PV owners that “Solar energy systems should be REGULARLY inspected & maintained to ensure they continue to function safely & efficiently”. “It must be performed by a licensed electrician”.See DOC/21/25432 with over 20 reasons. Quite a few roof fires have occurred. If you do NOT have a regular safety inspection, your insurance co. may not pay for roof fire {or life insurance if killed]?
As you note there may be additional requirements imposed by the network distributor or a state/territory.
Queensland has a similar guideline.
There is no requirement to engage an annual inspection, or maintenance service. There are simple guidelines on what is important. There is clear advice provided on what conditions require professional services. The requirements mirror the CEC advice on information to be provided by the installer/supplier.
It would be useful for all of us and other owners as to what they have been advised. Specific to their installers/locations.
Consider:
Some rooftop fires from solar PV systems have been attributed to faulty installations or poor quality/inappropriate components. An annual inspection is one way to reduce risk. Consider the as new installations are intended to have a 25 year lifetime, and household electrical installations are intended to be without fault for similar lifetimes. Inverters have 5/10 year warranties and panels longer. Is an annual inspection for safety reasons a negative indictment on the industry, the installers and quality of the products?
I’m not suggesting any consumer act differently to what the supplier has put in writing, or is provided by a mandatory direction. Whether those paying for annual servicing are receiving necessary activities and value for money needs further explanation. There are parallels with annual motor vehicle road worthy inspections. Each state is different with NSW the only state with a strict annual requirement for private use passenger vehicles from 5 years of age.
Assume the following might be useful for others with a 3 phase home connection. Like some of my neighbours whose shed roofs shine with as many panels as the network distributor will permit on our soft dead end line. There is some envy, although our single phase system is all we need.
We’re on a slightly different theme from the OP discussing upgrading solar PV. Something that may be done to replace/modify a defective system or to augment an existing system with additional capacity.
If we ignore the potential electrical safety issues and obtaining approval of a non-standard PV system, it would be far simpler and possibly significantly cheaper to install a standard (off the shelf) PV battery system, with an increased cells output to meet your desired generation capacity. The only challenge may be obtaining approval for a higher feed in capacity if the local distribution network is near capacity for PV feeds. This may be able to be circumvented by choking the output of the new inverter to the existing approved feed in flows.
There is an assumption in the discussion any system will be designed and installed by a CEC accredited business. Depending on where your property is located, systems which are more powerful behind the meter may be approved, conditional on export limiting being implemented.
What is technically possible? For the average consumer, what will the authority in a particular circumstance permit? One pathway and my preferred option is to firstly discuss your needs with several reputable local CEC accredited suppliers. Preferably ones with design certification, and the local authority if uncertain if what advised is acceptable.
Here in Qld they count the inverter capacity for any connected system. So for single phase it is 10 kW max connected inverter capacity, as a AC battery has an inverter in these household situations and is usually a 5 kW one a single phase connected property can have a 5 kW inverter from the panels and a AC battery (eg Tesla type). If they have a 10 kW or 7 kW inverter or 2 X 5 kW inverters and wish to add a AC battery this is counted as over the 10 kW allowance.When this occurs it means a house must have 3 phase power supply connected. DC batteries do not count as they do not have inverters.
There can be substantial delay in getting approval for the 15 kW or larger as we have just experienced. We had the single phase replaced by 3 phase in about September (we had connected 10 kW and wished to add a battery), even this change to 3 phase needs Energex approval and Energex must attend to connect supply at the pole or the ‘green boy’ (in suburbs where poles are not used a box is outside the property with a green plastic cover). Then a new 3 phase meter must be installed and connected, this was done about 4 weeks after the 3 phase line was run to the house and the Energex work on the ‘green boy’ was completed. Then we had to await connection approval for the 15 kW capacity, really only 10kW is the max possible outflow but as the battery is connected to it all this is counted regardless. Only a week or so ago Energex finally approved the connect of the battery and it will be installed early this month. All up about a 5 month hiatus for us, some will be faster and others slower in happening.
Inverter output to the grid can be limited by a setting in the inverter software, but this limitation is disregarded by Energex when making decisions about Connect approval, it is based purely on the actual capacity of the inverter or inverters and/or battery or batteries. The export limitation does however apply when a single phase property has 10 kW of inverter capacity as Energex require export in single phase to be limited to 5 kW.
“ 5.4 Inverter Phase Limits: Single phase inverters, are acceptable up to and including 10kVA of installed capacity on a customer’s installation, however total export shall be limited to 5kVA or less via partial or minimal export operation, as per Section 5.9.1. Proponents with a single phase service wishing to export greater than 5kVA will need to make application with their retailer to upgrade their service to two or three phases.”
Solar Quotes has covered choking/hobbling/export limiting in the past and the article us worth reading:
It is interesting that Energex doesn’t allow inverter limits to be set, like available in other areas of the country. Maybe they are concerned that someone may change the settings in the future to increase limits greater to that approved. A technical solution could be to design and program a meter to do such which would be in control of the meter owner to manage. It appears that this solution is available, but the inverter needs its own meter installed.
It may be a misinterpretation of the previous posts. Energex requires the inverter limits to be set. Which is what the following appears to be saying.
The 10kVA per phase of grid connected generation and 5kW export limit per phase is typical for most residential or small customer connections in the NEM. For Energex and Ergon export limitation is a soft setting if I’ve read STNW-1170 v.8 sect 4.3.1.1 and 4.3.1.3 correctly. The reasons for limiting the total generating capacity per phase and connected to the grid behind the meter are more complex.
Curiosity Corner, Maximum Capacity (without negotiated approval):
For a residential customer with a total 30kVA (3 phase) solar PV system, 40kW of rooftop panels. Assuming a nominal 200W per square meter of usable roof space the average Australian home would be one giant solar panel. Or approx 133 x 300W PV panels.
