http://www.sequoiapublishing.com/pdt_pocketref3ed.htm

I use this thing all the time--well worth the price!

Not all electrical by any means, but a good general "shop reference". It won't replace copies of the NEC, Machinery's handbook, and the CRC handbook, but it makes a great "first stop" for basic info on everything from wire ampacity to tap/drill sizes to the periodic table.