The members of the International Brotherhood of Electrical Workers Local 1928 say they rejected the contract offer because current members were being asked to pay more into their pension plans.
The union also says it objects to pension plan changes that would deny new employees access to the existing pension plan of the Emera Inc. (TSX:EMA) subsidiary.
A company spokesperson says that Nova Scotia Power's pension plan faces a shortfall and customers are expecting the company keep pension costs under control.
The union has been without a collective agreement since March 31, and talks with a conciliator broke down on Oct. 5.
The union represents about 1,000 workers at the power utility.