Buying the EV is the easy part. Getting the charger wired safely and to standard is where a registered electrician earns their keep. This guide explains the electrical fundamentals so you know what a good installation looks like. EV charger installation is notifiable work — always use a registered electrician and insist on a Certificate of Compliance (CoC).
1. A dedicated circuit
SANS 10142-1 requires an EV charger to run on its own dedicated circuit straight from the distribution board — never shared with plugs or lights. A 7.4 kW charger draws a continuous 32 A at 230 V single-phase, and continuous high loads are exactly what shared circuits handle badly.
2. Single-phase or three-phase?
- Single-phase (7.4 kW / 32 A): the default for most homes. Adds ~40 km of range per hour.
- Three-phase (11–22 kW): only if you have a three-phase supply and spare capacity. Check your main breaker and utility limit before assuming you can go faster.
3. The right protection
This is where EV circuits differ from ordinary ones:
- Dedicated MCB sized to the charger (typically a 40 A curve-C breaker for a 32 A charger).
- Earth-leakage protection that handles DC fault currents. EV charging can introduce smooth DC residual currents that "blind" an ordinary Type AC RCD. You need either a Type A RCD with 6 mA DC detection built into the charger, or a Type B RCD upstream. Confirm which your charger provides.
- Surge protection. A charger is an expensive electronic load — protect it (and everything downstream) with a suitable surge arrestor.
- Isolation. A local isolator lets the unit be safely worked on without killing the whole board.
4. Cable sizing
Cable must be sized for the continuous current, the run length (voltage drop) and the installation method. As a rough starting point a 32 A charger on a short run is often wired in 6 mm², stepping up to 10 mm² for longer runs or where derating applies. Your electrician does the actual calculation — never guess cable size on a continuous load.
5. Earthing and the open-PEN question
Correct earthing is critical for EV points because a person can be touching the car while it charges. Your electrician will confirm the earthing arrangement and, where required, provide open-PEN protection. This is not optional detail — it's the safety case for the whole installation.
What Ampworks supplies
We stock the switchgear that makes an EV circuit compliant: circuit breakers, earth-leakage units, isolators, surge arrestors and correctly rated cable and accessories from CHINT and other trusted brands. Not sure what your board needs? Send us your charger spec and we'll help you build the parts list — then hand it to your electrician.