By Peter Biles
BBC southern Africa correspondent
"Load shedding" is suddenly South Africa's most commonly used phrase.
Middle-class suburbs are not as used to the power outages
The state's power utility, Eskom, says load shedding occurs when it becomes necessary to interrupt the electricity supply because demand cannot be met.
More simply, load shedding is a euphemism for the blackouts that have beset the nation for the past two to three weeks.
The traffic in Johannesburg is at a standstill more than usual at the moment.
With the lights out, there is chaos at intersections as frustrated motorists find their journey to and from work taking twice as long.
Callers to local radio stations are talking about little else except the power cuts.
One Johannesburg-based station, Talk Radio 702, has supplemented its traffic reports with "power reports", updating listeners on when and where to expect the next round of electricity cuts.
Residents of South Africa's black townships are no strangers to power outages. They have been accustomed to cuts ever since electricity was introduced in the townships.
But the predominantly white, middle-class suburbs are also now being affected in a way which they have not been previously.
Restaurants have been particularly hard-hit.
"We're without power up to four times a week, often at our peak time in the early evening," says Lizaan Joubert, the manager of the Orient Restaurant at Melrose Arch in Johannesburg.
"It puts enormous pressure on our kitchen, and it affects the menu. Our customers remain loyal to us, but from a business perspective, this is the worst thing that's happened to us."
Across town in the suburb of Orange Grove, Rona Sonnenberg is increasingly anxious.
She suffers from emphysema and needs a steady supply of oxygen from a special machine powered by electricity.
Mrs Sonnenberg, who is in a wheelchair, says it is especially worrying when the power goes off without warning at night.
In the dark, she has to switch over to portable oxygen cylinders.
"It's pretty scary," she admits.
At hardware stores, sales of generators are booming.
This may be a quick-fix solution for those who can afford it, but it hardly inspires much confidence in a country that has traditionally been Africa's powerhouse.
People are using candles instead, such as in this book shop
Eskom has warned South Africans that they could face power shortages for the next five years.
Hopes of achieving 6% economic growth by 2010 when South Africa will host the Fifa World Cup, are fast fading.
However, Eskom's Managing Director of Corporate Services, Steve Lennon, insists that the country is not "going to the dogs".
"These are growing pains, and the shortage of capacity is not because our infrastructure is falling apart, but because our economy is growing," he said.
"That means an increase in demand for electricity which is running at 4-5% a year."
Mr Lennon says Eskom is "very uncomfortable" with the current situation.
"We don't like load shedding. It's not something we're used to. It's not something we want to get used to."
The South African government says almost 90% of the country's electricity is generated by coal-fired power stations.
The Koeberg nuclear power station near Cape Town provides 5% of capacity and hydroelectric and pumped storage schemes make up the rest.
Eskom has ambitious expansion plans for the next four years, but the company's current difficulties stem from a failure by government to approve capital expenditure programmes in the late 1990s.
South Africa has been exporting 5% of its electricity to neighbouring countries, including cash-strapped Zimbabwe.
Traffic lights without power means long queues
Eskom says that power exports are reduced when there is a shortage at home.
However, the opposition Democratic Alliance has called for the cancellation of power contracts with other Southern African Development Community states.
"It is clear we are facing a national crisis, and are not in a position to look after other countries' electricity requirements," the DA public enterprises spokesman, Manie van Dyk, said last Sunday.
However, Azar Jammine, chief economist at the Econometrix consultancy in Johannesburg, points out that South Africa also imports electricity from the huge Cahora Bassa dam in Mozambique.
"If South Africa cuts off power supplies to her neighbours, it may only complicate the agreements that are in existence."