Wednesday, August 28, 2013

Electric Fences, Where to Start?

Lets's talk fence chargers and their application.
I can help you to understand the infamous Joule measurement if you like.
I am the owner of Taylor Fence Inc.
My name is Mark Taylor.
I am trying this blog to see if I get any interest in discussing fence chargers and their application.
What information do you need to know to build an electric fence and to pick out the best fence charger for the job?
1. Climate
2. Soil
3. Length of the fence
4. Will the fence be kept clean or will it grow up.
5. How many corners
6. How many gates or drive-throughs
7. What conductor or wire will I use
8. How will I connect the wires or conductors
9. What insulator will I use or will the post be an insulator
10. What am I trying to keep in or out
11. Have the animals ever been in an electric fence
12. How bad to the animals want out or want into the fenced area
13. How many ground rods and how to space them
14. Can I bury the electric fence for a distance


  1. Mr. Taylor if I have 247 acres, the relative humidity of soil is bad, the question is : which energizer ( for 120 Vac) is more convinient ( how many joules); how many ground rods need. The Project is build many paddocks, about 4 acres each one.
    which is better in the case of ground rods: copper rods or Steel rods?. I most say you I have been using copper rods for ground with good results

  2. Mr. Chang,
    These are very good questions. I do wonder how dry your soil is. If it is very dry (sandy, almost desert) then you will do better to make some of your fence conductors ground. I don't know how many conductors you have in your fence but if you have several conductors, you may want to alternate ground and hot. If you have a good conductor, this makes it as if the animal were touching both terminals of the fence charger when it connects between the hot and ground conductors. Then you are not relying on the moisture in the ground at all but the animal only gets shocked when it connects between the hot and ground conductor. If there is moisture in the ground and the animal contacts a hot conductor, then it will still get shocked. Normally you would want the bottom an top conductors to be hot. A large charger can not overcome very dry sandy soil but a larger charger will always be more effective.
    For the 247 acres with paddocks, I would recommend a 20 joule or larger charger. It will be hard to find a single battery charger this large but a joule is a joule whether it comes from a charger powered by a battery or from AC (120V).
    A rule of thumb is to put in one ground rod and then an additional ground rod for each 5 joules of power. ( for a 20 joule charger that would be 1 + 4 = 5 ground rods )
    Copper rods are the best. Galvanized steel rods are the norm and do a sufficient job using the rule of thumb. The most important thing is to make a very good connection to the ground rods. A 12 ga. copper conductor would be good for you to run to connect to the copper ground rods. Use an antioxidant paste (available at Lowes etc) to coat the connections and make sure the connection is tight.
    For as much fence as you are going to be installing, it would be advantageous to parallel the hot wires. If you will connect the hot wires together at each end of each fence section, it will conduct the power around the fence much better.
    I hope this is helpful to you.

  3. Mr. Taylor
    Thanks a lot for your kind attention, your mail is a great help. Now, I want to ask you, how can I measure how many joules an energizer have. I mean using basic electric tools ( high voltaje voltmeter, ammeter). I know that 1J=1Watt x s.
    I can measure the voltaje across primary coil of transformer; across the pulse capacitor; across the SCR

  4. Mr. Chang,
    You can determine the stored joules by measuring the stored voltage across the storage capacitor. If you can record with your voltmeter the max reading then that is the number you can use in the calculation, but if your digital volt meter does not have this function, you can unplug the transformer and read the max value or charge on the storage capacitor inside your fence charger. Please be careful. The AC voltage can be deadly and the stored voltage and the pulse can make you hurt yourself. The formula is Stored Joules = SV X SV X C X 0.5 where SV is stored voltage and C is the storage capacitance. For example if your stored voltage is 600 volts and the storage capacitor is 20 MFD then I square the voltage and multiply by half the capacitance or 600 X 600 X 0.000010 = 3.6 stored joules.
    The stored joules are used by some manufacturers for advertising.
    The output joules are much more important and depending on the efficiency of the transformer which varies from 0.5 to 0.8 you can determine the output joules. This is the power your fence charger delivers to the load. It is much more difficult to measure the actual output joules and requires expensive equipment. I hope this is useful information to you.