Design
Do I need three-phase solar for my South African home?
Only if your municipal supply is three-phase or you have large simultaneous loads (workshops, big heat pumps, ~11–22 kW EV wallboxes). Most suburban homes run happily on a correctly sized single-phase hybrid. Forcing three-phase equipment onto a single-phase supply does not work — start from what the meter and DB actually are.
Updated 26 October 2026 · Illustrative ranges — not a formal quote or legal advice.
Answer first: Match the inverter to the supply you already have. A typical Johannesburg, Cape Town, Tshwane or eThekwini suburban home on single-phase can take a 5–8 kW hybrid and a 7.4 kW AC wallbox without inventing three-phase. Upgrade the municipal service only when measured loads, workshop tools or faster home charging truly need it — phase upgrades cost time and fixed charges, not just hardware.
How to tell what you have
- Look at the municipal meter and main breaker labelling (1φ vs 3φ, or “220/230 V” vs “400 V”).
- Count live conductors into the DB with a registered electrician — three-phase usually shows three lives plus neutral.
- Check your account’s capacity / circuit-breaker size; three-phase services often carry higher total kVA.
- Photo the meter for every quote request so installers stop guessing.
Why EV owners ask
Home AC chargers up to about 7.4 kW fit many single-phase installs if the DB and diversity allow. Wallboxes at ~11–22 kW usually need three-phase. Public CCS2 DC fast charging is a different product — you do not need three-phase at home to use highway DC. See charger power levels, three-phase home EV, home charger cost.
Solar inverter sizing on single-phase
Distributors apply NRS 097 simplified connection limits per phase. A single-phase home might sit comfortably at 3–5 kVA export-capable inverter capacity under “simple” rules, with larger sizes needing more scrutiny — confirm your metro. Oversizing PV watts on a smaller inverter (DC:AC ratio) is common; that is not the same as changing phase count — inverter size, max SSEG kW, NRS 097.
Bill and tariff angle
Three-phase capacity can raise network / capacity charges even when your kWh drops after solar. Model fixed charges from your 2026/27 schedule before celebrating a faster wallbox. Self-use of PV still beats export credits (~152.93 / 143.29 / 184.60 / 108.25 c/kWh incl. across Cape Town, City Power, eThekwini, Tshwane). TOU customers should park big EV draws in off-peak or midday solar windows — TOU / prepaid + EV.
When a phase upgrade can pay
- Workshop welders, large three-phase motors, or commercial tools already on site.
- Heat pump + EV + induction cooking peaking together beyond single-phase diversity.
- Estate or smallholding with long cable runs where three-phase distribution was planned anyway.
Municipal service upgrades involve application fees, possible transformer work and weeks of scheduling — put them on the critical path beside SSEG, not after panels are on the roof.
Balancing and backup quirks
Three-phase hybrids must respect per-phase backup limits; a single heavy load on one phase can trip backup even if total kW looks fine. Single-phase homes should still split essential vs non-essential so the geyser and stove do not eat the battery.
Quote checklist
- Confirmed supply type and main breaker rating.
- Inverter model phase count matching the supply.
- EV charger kW and whether load management is included.
- Any municipal phase-upgrade scope, cost and lead time.
- SSEG forms reflecting the final phase configuration.
SA caveats
Never buy a three-phase inverter for a single-phase meter “for the future” without a dated upgrade plan. Informal DB changes without CoC create insurance and sale headaches — CoC. Educational only.
Quick FAQ
Does three-phase solar make more power from the same panels? No — irradiance and array size dominate.
Can I run a three-phase heat pump on single-phase solar? Only with the correct supply and starter design — ask the heat-pump OEM.
Is public DC charging a reason to upgrade? No.
Diversity, main breaker and load management
Single-phase homes often sit on 60 A or 80 A mains. A 7.4 kW EVSE plus geyser plus kettle can trip diversity even when the solar inverter is happy. Load-management EVSEs that pause charging when the main CT approaches the limit preserve single-phase viability — EV load management. Three-phase spreads the same toys across phases but still needs per-phase awareness on backup.
Inverter backup ratings vs phase count
A 5 kW single-phase hybrid might deliver ~5 kW on essentials. A 10 kW three-phase hybrid is not “10 kW on any one phase” — many units limit per-phase backup. Read the datasheet before moving the oven onto essentials “because we went three-phase.”
Municipal upgrade practicalities
Service upgrades can require wayleaves, meter relocation, and proof of COC on the new main. Lead times vary by metro depot. Parallel the upgrade application with SSEG so you do not energise a three-phase inverter on a still-single-phase meter. Keep the old tariff schedule PDF so you can compare fixed charges before and after.
Worked decision tree
- Confirm supply with photos.
- List simultaneous peaks (EV, heat pump, workshop).
- If peaks fit single-phase with load management, stay single-phase.
- If not, price phase upgrade + three-phase hybrid against delaying the EVSE size.
- Only then pick hardware.
Pillar reading: EV charging guide, home solar guide (if present) or how solar works.
SSEG simplified limits reminder
NRS 097-2-3 style simplified connection criteria often scale with the number of phases and the local LV network. A three-phase service can accept a larger aggregate inverter rating under “simple” processes than a single-phase service — but that is not permission to ignore your metro’s forms. Confirm numbers with the distributor before you buy a 12 kW three-phase hybrid “because the neighbour has one.”
Heat pumps and induction kitchens
Modern heat pumps and induction hobs create sharp peaks. On single-phase they compete with EVSE diversity; on three-phase they can be balanced if the electrician distributes circuits intentionally. Whole-home planning beats buying phases in isolation — heat pump + solar + EV.
If you are years away from an EV, do not pay for a three-phase upgrade “just in case” unless a workshop load already justifies it. Conduit and DB space for a future wallbox is cheaper optionality than a live service upgrade.