Electrical safety
Solar earthing and bonding in South Africa — what should be on my quote?
Solar adds metal on the roof and electronics in the garage. Earthing and equipotential bonding tie exposed conductive parts to a safe reference so faults and surges have a path. Your quote should include bonding of module frames/rails, inverter earthing, and coordination with SPDs — verified by a registered electrician on the CoC.
Updated 26 October 2026 · Illustrative ranges — not a formal quote or legal advice.
Answer first: Earthing and bonding are not optional extras on a solar quote. Module frames, mounting rails, inverter chassis and battery enclosures need a deliberate earth/bond design that a registered person can test and record on the Certificate of Compliance (CoC). Skipping it to shave a few hundred rand is how insurers and buyers later argue about fault damage — and how lightning or DC faults find the wrong path through your Wi-Fi and DB.
Why homeowners should care (savings + risk)
A tripped inverter or damaged BMS after a storm can wipe weeks of tariff savings. Metro retail kWh still sit in the multi-rand range on upper residential steps in 2026/27; downtime is lost self-use. Proper earthing also supports SPD performance — surge protection — so the suppressors actually clamp to a shared reference instead of fighting floating metal.
Homeowner checklist (non-wiring)
- Ask for a simple bonding sketch or photo of earth connections on rails and inverter.
- Confirm the earth electrode / existing earthing system was inspected or tested.
- Reject floating metal rails and “we’ll earth later” verbal promises.
- Ensure DC and AC SPD locations are shown on the single-line diagram.
- Keep the CoC with your SSEG pack — sales and claims handlers ask for it — what is a CoC?.
This page is educational, not a wiring method. SANS 10142 (and related PV practice) plus the inverter/battery manuals govern the detail your electrician must follow.
What “equipotential bonding” means in plain language
Bonding ties conductive parts together so they sit at a similar potential during a fault. On a roof that means rails and frames are not isolated islands. On the wall that means the inverter earth terminal is actually landed on the site earth system. When lightning energy or a DC insulation fault arrives, you want a designed path — not the HDMI cable into the TV on backup circuits.
Coordination with SPDs and cable runs
Long DC strings on SA metal roofs act as antennas. SPDs at array and inverter ends only help if earth impedance and bonding are coherent. Undersized earth conductors, painted-over bond points, or rails bonded in one corner only are classic snags. Cable sizing belongs on the same drawing — cable sizing.
Batteries, EV chargers and outbuildings
Garage battery walls and wallboxes add more metal and sensitive electronics. Treat them as part of the same earthing conversation: chassis earths, correct AC protective conductors, and whether a separate outbuilding needs its own electrode strategy per the electrician’s assessment. EV charger CoC scope: EV wiring & CoC.
Quality signals on the quote
- Line item or clear inclusion for bonding / earthing materials and labour.
- SPD type/location called out (not “as needed”).
- Registered person named for CoC.
- PV GreenCard or equivalent quality process if offered — still not a CoC substitute — PV GreenCard.
- As-built photos promised for your handover folder.
DIY red flags
Roof work on live DC, borrowed “earth stakes” from hardware aisles without testing, and bonding with random braided scraps are how people get hurt. Use a registered installer — DIY risks.
SA caveats
Coastal corrosion, Highveld lightning density and dusty rail joints all attack bonds over time. Re-torque and visual checks during annual maintenance are cheap insurance — maintenance. Municipal SSEG approval does not inspect every clamp; the CoC is your legal record.
Quick FAQ
Is the Eskom/municipal earth enough? Your electrician must verify the installation’s earth continuity — do not assume the street connection alone covers new roof metal.
Do microinverters change bonding? Follow the module/rail and OEM rules; bonding still matters.
Will GreenCard replace earthing detail? No — it may document quality, but CoC + SANS practice remain mandatory.
Lightning-prone and coastal sites
Highveld storms and KZN/Cape coastal corrosion attack bonds differently. Coastal installs need corrosion-aware hardware and inspection intervals; Highveld sites need SPD strategy that assumes frequent transients. Neither is solved by a single earth stake photo on WhatsApp. Ask the electrician how they tested earth resistance / continuity and where the results live in your handover pack.
Array frame bonding details homeowners can spot
Without touching live parts, you can still look for dedicated bond straps or conductors between rail sections, paint scraped at bond points as specified, and earth conductors that are green/yellow and landed, not coiled “for later.” Loose hose clamps on painted rail are a smell test failure. Report concerns before final payment.
Battery wall and inverter earths
Wall-mounted hybrids and battery cabinets have labelled PE terminals. Floating chassis plus plastic trunking aesthetics are a bad mix. Ensure the installer did not “tidy away” the earth to make the garage Instagram-ready. Parallel packs should follow OEM earthing notes — random extra earth loops can create noise issues on BMS communications.
Handover pack contents
- CoC referencing the solar/battery work.
- Single-line diagram with earth/SPD symbols.
- Photos of rail bonds and electrode connections.
- SPD model numbers for future replacement.
- SSEG approval letter when issued.
Quality process optional extra: PV GreenCard. Mandatory electrical record: CoC.
Common quote omissions that cost later
Watch for: SPD “optional”; no rail bond line item; “earth existing” with no test; battery cabinet earth left to the owner; EVSE added later without revisiting bonding. Each omission is a future call-out fee. A complete electrical section on the quote is cheaper than unlocking the roof twice.
Relationship to insurance wordings
Insurers increasingly ask whether the PV system was installed by a registered person with a CoC. After surge damage they may ask about SPD presence. Earthing photos in your handover pack shorten those email chains. Keep them with the GreenCard/as-built if you have one.
Educational reminder: this is not a method statement. Your registered electrician decides electrode strategy, conductor sizes and test instruments under SANS practice and OEM manuals.