BOSTON & SAN FRANCISCO--(BUSINESS WIRE)--Calera Capital, a leading middle-market private equity firm, announced today that it has acquired Thayer Power & Communication in partnership with management. Thayer is a leading provider of mission critical repair, maintenance, and upgrade services for the utility and telecommunications industries. Terms of the transaction were not disclosed. “Thayer’s demonstrated ability to consistently deliver safe, reliable and high-quality service to its utilit.