IEC 60045-1:2020 is applicable primarily to land-based horizontal steam turbines driving generators for electrical power services. Some of its provisions are relevant to turbines for other applications. Generator, gear box and other auxiliaries which are considered as a part of the system are also mentioned in this document. Detailed specifications for this equipment are not included in this document. The purpose of this document is to make an intending purchaser aware of options and alternatives which it may wish to consider, and to enable it to state its technical requirements clearly to potential suppliers. Consequently, final technical requirements will be in accordance with an agreement between the purchaser and the supplier in the contract. This second edition cancels and replaces the first edition published in 1991. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) Scope clarification and boundaries of applicability; b) general update to state-of-the-art technology; c) integration of product safety: Clause 5; d) integration of automation, incorporating the former annex on electronic governors: Clause 11; e) Informative Annex A on welding added.