Electrical Troubleshooting Links
Background & General
Sharp on electric energy $aving questions.
Very good account of shocks by an engineer-type.
Big page with lots about other countries' electrical systems.
For the curious, this is how a GFI works (.pdf).
Very thorough on light bulbs.
Wikipedia's articles on Short circuit, and Receptacle testers.
Valuable Diagnostic Tool: This circuit breaker identifier leaves little need for guessing. I bought one and compared it with an expensive tool I have (that can do other things in addition) on seven circuits in my home. This "Circuit Detective" (not to be confused with me) did as well as mine. For the purpose of circuit identification, it is even handier than mine.
Speaking of detectives, The Energy Detective lets you track your home energy use.
Another retailer shows many useful testers available.