A Type J plug in South Africa?
Not directly — pack an adapter.
South Africa's Type M / Type N / Type C sockets don't take a Type J plug. A plug adapter solves the shape problem — it changes pins, not electricity. The wall delivers 230 V at 50 Hz (207–253 V within tolerance) — if your device isn't rated for that (look for "100–240 V" on the brick), an adapter won't save it.
Grid facts verified against IEC World Plugs — South Africa. Physical-fit verdicts derive from pin geometry and each socket standard's acceptance list — not safety advice.