Contract negotiations will resume on Thursday between PECO and the electrical workers union.
Workers have threatened to walk off the job on Saturday if a deal isn't reached by then.
Mayor Cherelle Parker sent a letter to both sides urging them to come to an agreement.
The union says the company is not offering serious counterproposals. PECO says it has offered 20% wage increases over five years.
The company says it appreciates the mayor's letter and says it is committed to bargaining in good faith.
