This is a basic introduction to electrical hazards that can be found at emergency scenes. It will give you the general understanding and sense of awareness to get you through most incidents.
(This is also the class taught at FDIC)
This class goes a little more in depth when it comes to securing utilities and mitigating more complicated electrical hazards. A brief explanation of the equipment and how it works together will help you understand what you are looking at and increase your situational awareness.