Does anyone know where I can find definitions to the ANSI device numbering system? What I am looking for are definitions to the numbers you see as part of medium voltage on line diagrams. (50/51N is one example) I have some of them from a previous job but I was wondering where I could get more info. PS: It's not worth it to me to spend $100.00 on buying the standard! ![Eek! :eek: :eek:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)