Electricity is 220/230 volt. Most north American and European plugs do not fit South African plug points. Plug adaptors are required for appliances from most overseas countries, and these are available from leading supermarkets as well as electrical and travel shops.
In 2006, South Africa's national electricity provider started running out of generating capacity. "Load shedding" means that different areas are periodically without electricity for a few (usually two) hours infrequently. That seemed to have provided the wake-up call to urgently address issues and load-shedding is hopefully a thing of the past. Many businesses invested in expensive generators for emergencies though.