[Inkscape-user] Inkscape symbol templates (newbie question)

I am relatively new to Inkscape, and am looking to use it for general vector drawings, but in particular drawing diagrams (single line electrical diagrams). As such, is there anything similar (sorry for the comparison) to Visio's symbol templates, where one can store recurring symbols and simply insert them (and create custom symbols to add as the need arises)? Any ideas on how best to manage this in Inkscape (or indeed any other recommendations?) would be greatly appreciated; likewise if there are any single-line symbols available?

Thanks,

Mattias