Phil Bowe, president of Local 310 of the Utility Workers Union of America, said the contract, if approved by members, will improve working conditions and provide better service for National Grid customers. He said the union is expected to vote on the offer next week.

“The reliable service that this company used to provide years ago when we were Narragansett Electric has really deteriorated since National Grid has taken over,” he said. “We feel that through added staffing and preventative maintenance that we can bring the company back to the way it was.”

With contracts representing some 1,300 National Grid electricity workers in Rhode Island, Massachusetts and New Hampshire set to expire at midnight last night, both sides had been preparing for a possible strike.

Last month, union members from Local 310 and six other locals voted to authorize their unions to call a strike, if necessary. National Grid, meanwhile, had said it was bringing in non-union management workers from its service territories in New York State to fill in for line workers in the event of strike. And yesterday, the company told its union workers to turn in all of their company equipment yesterday, such as their meter keys, truck keys, cell phones and company ID/keycards.

In a prepared statement last night, Cheryl LaFleur, acting president of National Grid’s electricity distribution business, said the tentative agreement, which affects about 1,300 workers in total, “is in the best interest of our customers, our employees and our company.”

“The agreement includes wage and staffing increases and other provisions that will enable National Grid to continue to serve our customers safely, reliably and efficiently,” she said.

Bowe said the additional positions will add to the ranks of employees who work with overhead wires and utility poles, those working with underground cables and networks and those working with substations that distribute electricity. He declined to say how many positions will be added but said the number would be significant.

The staffing issue was important to the union because of the potentially hazardous nature of the work and the large amounts of overtime employees have been working and the time it takes to train new workers, Bowe said. Under National Grid, Local 310 has lost about 100 workers, he said.

“The average age of the work force is nearly 50 years old. We have a lot of pending retirements coming up in the future,” he said. “These are jobs that take between four to six years to be proficient at. We have to start putting workers into the pipeline.”

Bowe said the contract also includes provisions to improve preventative maintenance of poles, wires and other equipment that should improve service.

National Grid is still negotiating with another union, the International Brotherhood of Electrical Workers, which represents about 575 workers. Those talks were expected to continue today, the company said.