ugly's electrical references handy for solar power

Today, I met up with Dennis Epp, founder of Hertiage Solar a leading solar power installer in Orange County and San Diego gave me a book called, Ugly's Electrical References. The reference guide is not a replacement for the national electric code (NEC) but provides the most common required information in easy to read format, which includes pictures and tables. The guide has the following relevant information that's important for solar electric systems.

• voltage drop
• Conduit size
• Cable type
  
• number of conductors that can fit in conduit or tubing.

Talking to customers, I've noticed people often have a difficult time figuring out wire size and voltage drop, after looking through Ugly's, I noticed it's a great resource to figure out these important elements of your solar electric system. It's important your system is designed correctly to meet NEC codes, otherwise it could be a potential safety hazard. What's your favorite electrical reference guide?