Solar Power at home in South Africa – can it become even more complex?
A MyBroadband article from February 2025, a top ICT news publication in South Africa, highlighted two key issues frequently mentioned by homeowners:
- Important information for solar power users in South Africa
- Big problem with solar power system prices
As a homeowner in Cape Town, I initially installed a small 5kW diesel generator with a certified electrician (and received a CoC). Later, I upgraded to a 5kW inverter, and then to an 8kW unit. Cape Town City subsequently issued a compliance list for SSEG (Small Scale Embedded Generation) units, all designed to be grid-tied.
Everything is understood 100%. My unit isn’t grid-tied but marketed as an “off-grid inverter”. However, it still relies on the power utility at night to charge the batteries. This is similar to having a UPS installation providing power to your home. If all heating appliances are gas-powered, one could provide power to each room through a dedicated UPS. However, there are more complex aspects to consider with this rule book.
DC Vs AC – Qualifications Vs Competency
Complications arise when homeowners install solar panels. An installer with DC qualifications is necessary – are solar installers qualified to fit DC panels that can generate kilowatts to hundreds of kilowatts? I argue not. They assert they are. Is your electrician qualified to work at PV voltages up to 1,000 volts? Certainly more so than the solar installer, and this in no way undermines their capabilities. I believe greater emphasis is now placed on DC components – battery and PV connections – rather than the AC component, connected to and from the inverter. However, the primary concern expressed by industry experts is that poor installations may result in back feeding, which poses significant danger to personnel working on the grid.
Electricians typically ensure safety by grounding phases to prevent accidents, such as lightning discharges. On the Power Forum website, various circuit configurations have been discussed to mitigate the risk of back feeding. This document does not cover the Current Transformer installed with a grid-tied inverter but rather examines off-grid installation enhancements proposed by experts.
Preventing Back Feed
Commonly used are low/high voltage dropout circuits and frequency monitoring systems, which disconnect the incoming AC supply to the inverter if voltage drops below or exceeds thresholds or if frequency varies by a few hertz. Another system involves a contactor disconnecting mains power when grid power is lost. Both circuits use Hager components, which Cape Town City and Eskom also utilize.
For further insight, please refer to this tender document, which indicates the products Eskom endorses. Additionally, I have included a document from Ecasa discussing the fundamental aspects of DC versus AC systems and the importance of caution.
Historically, Edison made advancements with DC, attempting to discredit Westinghouse’s promotion of AC since the electric chair operated using direct current—a shocking revelation indeed!
Reality Check – the cost (note no hardware supplied by the contractor)
To return to practical considerations, here are some findings from my setup and its legal compliance. The application was processed by an electrical engineer through city power at a cost of R12,000.00, for which I did not receive a proposed diagram. The electrician, despite not having seen it, proceeded to couple a grid-tied unit to an off-grid unit, along with batteries and the PV array installed three years prior. This incurred an additional R12,000.00. Finally, the electrical engineer inspected the installation—excluding the PV array—and confirmed the Certificate of Compliance (CoC) is ready and available.
I have a background in electronics, working with light current, ships, radar, gyro, navigation gear, and collaborating with ship electricians. My experience includes converters and inverters, which are more complex than home PV systems. I believe inverter manufacturers should be more involved by drawing up diagrams since they know their equipment best. If inverters follow City’s compliance list that adheres to NRS097 protocol, it simplifies the approval process, eliminating the need for costly R24 000.00 approvals.
A workaround which should make it cheaper and possibly more reliable
Manufacturers should work with distributors and provide on-site training for qualified technicians who can then sign off the work. This approach promotes sales and involves only electricians, ensuring consistency with configuration manuals. Additionally, is there regulation over the type of UPS entering the South African market?
Lastly…
Most portable generators for domestic use are designed for construction sites, featuring a floating neutral. How can one obtain a CoC for an installation connected to the house DB then?