*FOR A FULL TUTORIAL VISIT*:https://www.youtube.com/watch?v=B5r3ApPe8DM



You can't acutally make an electrical fence in minecraft, but I have figured out an alternative. I'm not here to tell you I did, I'm here to show you how. In order to make an electrical fence you need to have access to a command block. You need to type in:
/effect @p 7 10 3
The "7" represents INSTANT DAMAGE.
The "10" represents SECONDS.
Finally, the "3" represents how strong the potion is.
For more information please visit the video above.
Put the command block behind a block.
Run string from that block to another and connect the string using a tripwire holder.
Once you have done that you are ready to go, any player that crosses your string is dead.
Tip: Make sure you fence is in an area without any mobs, or a safe area that contains no mobs around because mobs can trigger the tripwire causing you, or another player, to die.

*FOR MORE INFORMATION VISIT THE LINK TO THE VIDEO PROVIDED ABOVE*