The grounding ensures that when an animal touches the fence, the circuit is closed, and the current flows through the animal. This creates the “shock effect” that you would like to see.
Excellent grounding is, therefore, indispensable for the optimum operation of the electric fence system. The ground must be such that there is a very low resistance, max 100 Ohm. Optimal is a copper or copper-plated earth pin with a diameter of approx. 20 mm, which is connected to the lowest groundwater level. However, this is not feasible in many places. To approach the excellent grounding, it is therefore recommended to communicate at least two earth pins of a meter (article 162-80199) parallel and in series with each other, with a distance of approx — three meters. If you want to get the most out of your equipment, the grounding is crucial. The installation can not work correctly without sufficient earthing.
- Measure the voltage on your earth pin with a voltmeter *. To do this, insert the reference of the voltmeter * into the ground at approx. 1 meter from the surface pin. This measured voltage must not exceed 300 Volts.
- Then measure with the voltmeter * that there are more than 3,000 Volt voltage on your fence at least 100 meters from the grounding. Here too, you put the reference of the voltmeter * in the ground.
- Ensure that a short-circuit is made at this measuring point by connecting the voltage wire to the ground, for example, by turning on a conductive (iron/aluminum) post.
- Measure the voltage on your ground again in this state. If it is more than 300 Volts, the earthing is insufficient, and you will have to install more earth pins to optimize your electric fence.
- After applying more earth pins, carry out the test again.
You take a blade of grass 15 or 20 cm long, you hold it between thumb and index at one end, and you put the other end on the wire. You gently advance the blade of grass, and at some point, if there is some current, you will feel a tingling in your fingers.
How to evaluate the physical earth in an electric fence?
The earth in an electric fence is essential, and to make the installation of it; we can use a Cooperweld rod of 3.00 meters. Or at least a cold water pipe, where the difference in alternating voltage concerning the neutral of the line is not greater than 2 Volts.
If the team does not have an excellent physical ground, the return to the individual will not be enough to impact it as we require it and very possibly will penetrate the perimeter.
The way to assess whether physical earth is correct, whether ground rod or cold water pipe, is based on performing three tests:
- With a voltmeter, this will tell us if the earth is working. The first test is to measure the 120 Volts power line to the equipment at terminals 1 and 2 of the terminal board. This voltage can be read with a voltmeter on the 200 VAC scale. In this test, we will observe that the power voltage will be between 110 to 127 Volts.
- The second test is using the voltmeter in the same way and scale, but now it will be to measure between terminal 1 or 2 and the physical earth. We must clean very thoroughly the point of the physical earth that we are going to evaluate to avoid false contacts. Consider that terminals 1 and 2 have alternating voltage, but one of the terminals will be live, and the other will be neutral. As we do not know which is which, let’s analyze the tests in the following way.
. Suppose that terminal 1 is live and terminal 2 is neutral. Careful, it may be the other way around, but the readings will guide us if we take the voltmeter and measure between terminal 1 (live) and physical earth, the reading should be the same as in test 1. If the reading is higher, we can begin to doubt a little of the truth of the earth.
- The third test is the most important since it defines how efficient our land is. Now we will proceed to measure the terminal 2 (neutral) against the physical earth, with the same voltmeter and on the same scale. The reading that we will expect must be between .2 Volts and 2.0 Volts. If the reading is greater than 2 Volts, the physical earth is no longer adequate, and it will be necessary to get another ground point. It is recommended to bury a physical earth rod 3 meters long, where we will surely obtain an excellent earth value.
Once finished evaluating our physical earth and considering it correct, it must be connected to the central terminal with the butterfly of the high-voltage output of the equipment, with a minimum of 14 AWG wire, and in turn join different ground points. Will offer us a better and more efficient physical land.