I put my name on this one because this article is very opinionated. First off, other than the flimsy 17 gauge electric fence wire that is sold in every farm store in the world, the other biggest problem associated with electric fencing tends to be with insulators. I am talking about inferior insulators and about situations that have left a bad taste in the consumer's mouth.
Over the years I have been to many farms/ranches and attended many trade shows invariably, there are always people that comment: Yep, we tried that electric fencing years ago and it didn't work for us. After a conversation, some listening and a few questions - in most cases those people were using inferior fence wire and inferior insulators on steel t-post or re-bar posts.
INFERIOR INSULATORS ON STEEL POSTS is an accident waiting to happen. If you have at least a little bit of an open mind you will probably agree that steel is the enemy of electric fencing. When you walk into most farm supply chain stores you will see bins full of insulators made to fit every shape of steel post. Many of them will be yellow in color. (You will notice that we have no yellow insulators.) The insulator business is a big business that is fed by an ongoing need to replace them. When an insulator fails (breaks or comes off the post) on a steel post you are most likely going to have a short to find and an insulator to replace. Many times one broken insulator will drop your fence voltage from a good high level to one that will not be respected by your livestock. Well, enough harping about steel posts and insulators, here are some comments about what to look for with insulators.
- T-Post Insulators: I fully realize that no matter how much we try to discourage this scenario, if you have steel T-posts on hand you are probably going to use them, so here are a few helpful hints. First off, use an insulator that is made to fit the size post that you have. In general there are two main grades of steel T-posts. The 1.33 and the 1.25. This indicates that those posts weight 1.33 pounds per foot of post or 1.25 pounds per foot of post respectively. With the huge increase in steel prices there have also been some 1.12 posts introduced recently. The profiles on these different posts are all just a little different. If you put an insulator that is made for a 1.25 post on a 1.33 post – it will be hard going on and it will probably stress the insulator assuring it to fail prematurely. If you put an insulator that is made for a 1.33 post on a 1.25 post, then it will most likely be loose fitting – easy to go on but also easy to pop off. If you have a pile of used steel T-posts then it is also likely that you may have a mixture of sizes, complicating it further. In summary, try to match up the right size insulator to fit the posts you will be using them on.
- Pinlock or Claw design: Although there are actually more options available, the basic choice for wire attachment is choosing between a claw style insulator or a pinlock style. In pull tests, generally the claw types are stronger than the pinlock insulators. But, there are convenience features of both. With the claw insulators, in order to remove the wire from the insulator, you may have to relax the wire tension so that you can tilt your fence wire for removal. With the pinlock, obviously you can merely pull the pinlock and the wire is then free. Some pinlocks fit tighter than others and are somewhat sensitive to heat or cold regarding insertion or removal. These two options are normally available for both T-post and wood post insulators.
- End Strain Insulators: End strain insulators handle all of the pull for your fence wire. I feel that you should NOT skimp on on these insulators. They do come in a lot of different composites and with different strengths. Among the material options include: porcelain, nylon, polymer and polyethylene. These materials can also contain glass and strength additives. It's all about the injection molding processes. To comment on the above materials here are my opinions: First off, I have never personally been in favor of porcelain insulators. I feel that they tend to get small hairline cracks in them and although that may not be a problem during dry weather, it does become a problem for shorts when those little hairline cracks fill up with water and moisture. Glass filled nylon is super strong and long lasting as are glass filled polymers. The polyethylene is weaker in strength. To determine the ground glass content is almost impossible without actually weighing them and comparing weights. Most packaging does not give you the material specs. We try to sift thru all the various types and offer the glass filled polymers. They are usually white or black in color. Our opinion is that the white glass filled polymers last the longest and are adequately strong for hi-tensile electric fencing with approximately 150 to 200 pounds pull. Another good choice of a little different configuration is the Black Double-U insulator (#P146). It has a metal band impregnated into the wire grove to keep the fence wire from wearing into the insulator. It is a proven performer also. Another feature that you should look for is deep wire groves to prevent twisting under tension as well as long leakage paths between conductive wire and tie wire. I hate to say that it may come down to price, but in general you will pay from $0.60 cents up to $1.50 each for a high quality end strain insulator. If you find insulators for less than $0.50 cents each, then I would question their quality and not put much faith in them.
In summary: Insulators are a major part and component of any electric fence system. They need to limit leakage from your system to maintain maximum voltage. If and when you can use INSULATED LINE POSTS you will be cutting down on the number of insulators that you have to use. Thus, you will have a better system with a whole lot less maintenance. It's just common sense, but it's your choice. Check out the Powerflex line posts and forget about line post insulator problems.