I really like this product: http://www.amazon.com/Code-Check-Electrical-Illustrated-Wiring/dp/1621137783/ref=pd_sim_14_12?ie=UTF8&refRID=07SGW53TBHV13ZBE63H9
It's cheap, and has a lot of diagrams, covers most of what a typical homeowner would need, and best of all is always on hand when you...