Online and free? If you find something let me know too! I followed a thread some time ago regarding IEC and JIC / NEMA type drawings, and all I could find online were for members only, by subscription, annual fee even for members, etc. IEEE is a pretty good, heavyweight organization, and they have standards published about this stuff.
There are certainly usefull books available in many public libraries about this stuff.
This may be a little out of place here, but I see you are shown as "(mechanical)", maybe you need an electrician more than a textbook tho. Naming devices and components in a way that's meaningful for those who must build, install, maintain (etc.) electrical systems is something you don't just pick up with an afternoons reading.
If you're up to it, get some copies of some electrical blueprints from a system (building, machine, etc) that is similar to what you're interested in.
best of luck
remember: An opinion is only as good as the one who gives it!