From the engineers at Mortissian Military Industries, we bring you the survival friendly, 100% eco friendly, command block free, redstone free (well, except for the on/off switch), guardian powered, electric fence in minecraft! Due to the fact that it doesn't use command blocks, we've incorperated guardians into the design, meaning that it will automatically sort out hostile threats to your home. Yes, you heard right, no more pesky squid wreaking havoc in the pantry any more! Our initial testing of the Guardian "Electric" Fence had our willing volunteers getting attacked four blocks away from the actual fence, and that was not okay. So we added a blinder system that reduced the range to be two blocks away from the fence when it kicks in (what we deemed as a more realistic range).

Specs:
Tower Range- The electric fence will need a tower every 12 blocks so that the guardians will be able to attack you. (10 iron bars between the tower and blinder).
Damage- The electric fence will deal approximately 12 () damage on normal difficulty to an unarmored player.
Charge Time- The fence will take around 3 seconds to fully charge between zappings. 
Range- When a player (or those pesky squid) get within 2 blocks of the fence the system will charge up and zap the unwanted visitor.
Size- Each section of the fence (with a tower at both ends) is 20 blocks long, 3 blocks wide, and 4 blocks tall.

Note: Some rewiring of redstone is necessary if you are planning to make the fence longer if you want to have an on/off switch.
          The trap doors may break when rotating the fence section. I have not found a work around yet. My apologies.
          Mortissian Military Industries is not responsible for any loss of personal items or deaths caused by using the Guardian
          "Electric" Fence.