This site is where (presumably) high-voltage current, carried from huge electricity pylons and copper wire, meets the earth, heading underground to nearby homes. The signs posted around the fence are supposed to help you with first aid in case you need to assist someone who's been electrocuted.
Of course, it goes without saying that when someone has just been electrocuted, it's highly unlikely that you'll have the luxury of time to read this board or surf the web for an answer. So take a moment, read this article, and do some more research on how to give first aid - you could save someone's life and prevent yourself from getting injured in the process.
Four points that may be obvious, but are key to remember, are:
- Switch off the power source
- Don't get yourself electrocuted
- You may have to start CPR
- High-voltage victims may have broken bones and internal damage - be careful if you have to move them