Electrical safety
Solar cable sizing in South Africa — what homeowners should ask
Cable size is about current, length and heat — undersized cable wastes power and can become a fire risk. Homeowners should not pick mm² from a blog and self-install. You should ask your installer to confirm UV-rated PV cable, short thick battery runs, correct AC tails into the DB, and that sizes follow the inverter manual and SANS practice.
Questions that protect you (without doing DIY electrics)
- Is DC array cable dual-insulated PV wire (not ordinary house wire on the roof)?
- Are battery cables kept short and sized for the inverter’s max charge/discharge current?
- Is voltage drop on long AC runs to a garage EV charger accounted for?
- Are MC4 / manufacturer connectors used — not twisted wire under insulation tape?
Rexel-style trade notes often cite 4 mm² PV cable for many domestic strings and 6 mm² for longer or higher-current runs — treat that as a conversation starter with your electrician, not a shopping list. Battery DC cables are a different (usually much thicker) problem.
Roof DC (PV)
UV/ozone-rated PV cable; string current and run length drive size.
Battery DC
High current — short runs, correct lugs, torque to spec.
AC to DB / EV
Breaker rating, earth leakage type, and length to the charger.
Stock for proper cable and glands typically comes through electrical wholesalers — another quiet reason installer supply chains matter. See wholesaler guide.