Techie_Junkie_PE_LEED_AP
PE, LEED AP, Ponderer of the abstract
Here's a link with some good info and nice graphics. This website has some other good articles that would help for the Power Depth. Mike Holt also has some good DVDs on NEC and other Power topics. They're expensive, but you can rent them from Smartflix.com.
http://ecmweb.com/training/electrical_basi...ing_basics_wye/
http://ecmweb.com/training/electrical_basi...ing_basics_wye/