IEEE Std 241-1990，IEEE商业建筑电力系统推荐规程，通常称为（灰色手册），由电气与电子工程师协会（IEEE）出版，为商业建筑的电气设计提供推荐规程。它是由工程师和设计师在自愿的基础上编写的，他们是IEEE电力系统工程委员会内的灰色工作组。对于商业建筑经验有限的电力工程师来说，这种推荐做法可能最有价值。它还可以帮助所有负责商业建筑电气设计的工程师。然而，它并不打算取代许多常用的优秀工程文本和手册，也不足以成为设计手册。应将其视为商业建筑电气设计的指南和一般参考。 从规范、标准和其他技术文献中提取的表格、图表和其他信息包含在本推荐规程中。它们的加入是为了说明目的；如果项目的正确性很重要，则应使用最新的参考文件，以确保信息完整、最新且正确。在本推荐规程中，不可能复制这些项目的全文。

IEEE Std 241-1990, IEEE Recommended Practice for Electric Power Systems in Commercial Buildings, commonly known as the (Gray Book) is published by the Institute of Electrical and Electronics Engineers (IEEE) to provide a recommended practice for the electrical design of commercial buildings. It has been prepared on a voluntary basis by engineers and designers functioning as the Gray Book Working Group within the IEEE Power Systems Engineering Committee. This recommended practice will probably be of greatest value to the power oriented engineer with limited commercial building experience. It can also be an aid to all engineers responsible for the electrical design of commercial buildings. However, it is not intended as a replacement for the many excellent engineering texts and handbooks commonly in use, nor is it detailed enough to be a design manual. It should be considered a guide and general reference on electrical design for commercial buildings. Tables, charts, and other information that have been extracted from codes, standards, and other technical literature are included in this recommended practice. Their inclusion is for illustrative purposes; where the correctness of the item is important, the latest referenced document should be used to assure that the information is complete, up to date, and correct. It is not possible to reproduce the full text of these items in this recommended practice.