A tentative settlement between General Electric and two unions representing 55,000 workers was reached last night, two hours before midnight, when the previous contract was to expire.

Neither management nor the unions -- the International Union of Electronic Workers and the United Electrical, Radio and Machine Workers union -- would disclose details of the tentative three-year pact.

A ratification vote by the rank and file could be held in about 10 days.

Union officials said job security, improvements in the cost-of-living formula, a general wage increase and early retirement were the main issues in the talks, held in New York. A GE negotiator said "the future competitiveness of GE's diverse businesses" was management's key issue.

In Maine, a union representing 4,500 shipyard workers at Bath Iron Works went on strike after voting overwhelmingly yesterday to reject the company's final contract offer calling for a three-year wage freeze.

About 50 workers began picketing outside the Bath yard at midnight, when the contract with Local 6 of the Industrial Union of Marine and Shipbuilding Workers expired. Picket lines also were planned outside BIW facilities in Brunswick and Portland.

On another labor front, negotiators for the state of Pennsylvania and unions representing 70,000 employes came up with 11th-hour proposals last night that averted a strike by all but two of 12 unions.

The Pennsylvania Social Services Union and the Pennsylvania Employment Securities Employes Association, which represent about 10,000 workers, broke ranks and struck at 12:01 a.m.

The other unions agreed to hold off on any job action until the rank and file votes on the new proposals, union officials said.

The three-year package reportedly includes an annual 3 percent wage increase, as well as changes in employes' holidays.