How an electric fence tester works

[drplokta]

1. Stick the earth spike in the ground
   
2. Loop the metal bit over the fence
   
3. Squint at the LED in the bright sunlight
   
4. Put your hand over the LED to shade it enough to see if it's flashing
   
5. Get your hand zapped with 3,000 volts
   
6. The fence is working