Research on engineering practice and its relationship with engineering education is getting increased attention in the engineering education literature recently. In this article, we present a study of engineering practice in an electrical power utility company that focused specifically on the learning practices of professional engineers. Through analyses of the data collected using an interview-based study, we constructed a typology of learning that demonstrates both the breadth and depth of learning in practice. We characterise elements of learning practices guided by a formal-informal continuum and an integrated technical-social dimension. Findings from this work speak not only to learning practices in the engineering workplace but also highlight an often-understudied aspect -- maintenance or routine engineering work. We argue that it is critical to provide a basic understanding of engineering learning that is relevant to a large proportion of engineering work focused on maintaining our technological infrastructure.