The National Union of Metalworkers of South Africa (NUMSA) has said its members will down tools on 1 July.
The union, which represents metal workers and other artisans, is demanding a salary increase of 12% for 22,000 of its 230,000 members.
It said the strike was inevitable after revising down its demand from 15%.
The longest strike in the history of the country ended on Wednesday after platinum workers returned to work after five months without pay.
Secretary general Irvin Jim said NUMSA is ready to take to the streets and withdraw its labour at an unprecedented level.
"We are going to strike, we are going to bring the industry to a standstill," said his deputy Karl Cloete.
Companies in the automotive industry and engineering sector said they cannot afford the union's demands.
There are fears that the strike could have a big impact on the construction of two major power stations that are already behind schedule.
The country's sluggish economic growth has been blamed in part on electricity shortages and the government has urged the unions not to go on strike.
"We are going to support all the affected parties to make sure this strike doesn't take place," said Communications Minister Faith Muthambi during a briefing in parliament.
Thousands of miners at South Africa's biggest platinum mining firms returned to work earlier this week.
Platinum firms estimate the strike has so far cost them more than 24bn rand ($2.3bn; £1.3bn), while employees have lost about 10.6bn rand in wages.