Three unions representing about 37,400 workers, went on strike against Westinghouse Electric Corp. at 12:01 a.m. today following a collapse in negotiations, officials said.
There was no immediate word on whether another union representing about 12,000 salaried employes, would join in.
"Westinghouse precipitated the strike by breaking off negotiations at 5:35 p.m. July 14 (Saturday), 30 hours before the contracts with the unions were due to expire," Mary Dresser of the Coordinated Bargaining Committee said it in a statement.
The committee represents the three striking unions - the International Brotherhood of Electrical Workers, United Electrical Workers, and International Union of Electrical Workers.
"We are prepared for a long strike," said Vincent Vingle, chairman of the International Union of Electrical Workers, which has 18,500 Westinghouse members.
Meanwhile, the corporation continued separate talks with the Federation of Independent Salaried Unions, representing 12,000 workers.
On Thursday, the three unions turned down a proposed three-year contract offering wage increases totaling $2 per hour, as well as cost-of-living boosts.
Westinghouse said the proposal was roughly equal to the agreement accepted last week by 120,000 employes of General Electric, but union officials said the offer "cut corners" on the GE package.
The unions estimate the average wage under the current pack is $6.25 an hour.