The International Brotherhood of Electrical Workers Local 1928 says the protection came in exchange for closing the existing defined benefit pension plan to new entrants.
The union said Friday that 68.4 per cent voted in favour of the deal, with 66 per cent of the membership casting votes electronically.
In a statement, Nova Scotia Power says its executive board and the union agreed to present a tentative agreement to members in July.
The utility’s president and CEO, Bob Hanf, says the agreement should bring savings and job security.
Nova Scotia Power said last October that it was looking at outsourcing work in a bid to cut costs.