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Planning Guides > Product Selection Guide > Ground Rods Guide, continued
8. Electric Fence Ground Rods Guide, Cont'd. While on the subject of completing circuits, it's worth noting that it is not necessary for the charged conductor on the electric fence to come full circle in order to "complete a circuit" because the pulsed charge that travels outward along the electric fence conductor should register well at the end of the electric fence line whether or not that line goes full circle. It is only important that all sections of this electric fence line be well-connected to the electric fence charger's output terminal or to some other properly charged portion of the electric fence. Expert Recommendations and Common Sense The electric fence experts whose conclusions appear in catalogs, instruction manuals, etc. recommend everything from a little two-foot ground rod to a series of massive six to eight-footers grouped in a cluster or strung out at regular intervals along the electric fence line (for our catalog offerings see Electric Fence Ground Rods). In reality, the most important guide to use in purchasing and installing ground rods and ground wires is common sense. What carries the electric fence charge from the feet of a target animal to the electric fence ground rod is not soil and rocks but rather the water in the ground. Water in liquid form is not nearly so good a conductor as metal in any form, and so it is essential to ensure a good connection between the metal ground rod or ground wire and whatever soil moisture carries the charge through the ground from the feet of the target animal. This means that the minimum requirement is for an electric fence ground rod in good permanent contact with moist soil. If the electric fence is short, and if it protects a well-watered summer garden, then a two-foot ground rod may well suffice. However, if multiple fences are involved, or if there is any question about soil moisture having good access to the rod for the entire time the electric fence is working, then a six-foot ground rod should be considered. In dry areas, three or more rods should be placed in a moist location and wired together. If the electric fence system extends out more than a quarter-mile from the electric fence charger, then additional ground rods should be placed at quarter-mile intervals along the electric fence line and connected to the rest of the ground system by means of a neutral (uncharged) ground wire. Also, even a short winter electric deer fence must cope with snow, ice, and frozen ground, none of which are good conductors. In these circumstances it is wise to get the metal grounding system as close as possible to the target animal—which is why we recommend stringing a 12.5 gauge wire (in the catalog see Conductors: Aluminum Electric Fence Wire, product 02-07) on or just under the ground along the electric fence line and connecting it to the electric fence charger's ground terminal. It may also be advisable to remove some of the snow and ice buildup along the electric fence line in winter—either manually or with a de-icer—in order to improve the grounding of the system. Replacing Ground Rods Electric fence ground rods and ground wires in contact with the soil take a lot of punishment. Especially where there is a significant weed burden, they are almost continually receiving some electric current, and the passage of electrons, through a process of ionization, strongly stimulates corrosion. Such corrosion attacks both the actual rod or wire and the ground system's connections, eventually reducing the system's effectiveness to nil. For this reason it is wise to inspect any electric fence ground wire periodically for corrosion and to replace ground rods every two years. (It is not necessary to dig up the old rods, but new ones need to be installed and connected to the charger's ground terminal with fresh connections.) Alternatively, one can test the electric fence system regularly with a digital fence tester (see Electric Fence Testers in the index below) and can replace the rods when significant voltage reduction not attributable to other causes is observed. |