Cheaper Alternatives to the Robotic Mower Boundary Wire

Does the boundary wire for the robotic mower seem too expensive to you? Do you suspect there could be cheaper alternatives? You are not completely wrong. The manufacturers of the common brands are already pocketing a certain amount of money as profit, so it is not wrong to look for cheaper alternatives that do the same job.

What alternatives are there to the original robotic mower boundary wire? As an alternative to the original boundary wire made for robotic mowers, most other types of weatherproof cables can be used. As a proven, low-cost alternative, military resale Field Telephone Wire are a great choice. The most important aspect of a replacement cable is a suitable, hardy insulation.

In general, you can use any type of electrical cable that is designed to conduct electricity in place of the typical boundary wires for robotic mowers. However, if you are looking for a cable that can withstand the weather conditions outside and at the same time is cheaper than the standard robotic mower boundary wire, the choice is already limited to a handful of cable types. In the following I will discuss these cables.

Contents

What Must the Cable Be Capable Of?

First of all, we should roughly define what the cable must actually be able to do. The cable must:

Be able to withstand the weather conditions in your yard for several years
Be covered with a robust insulation that will not be damaged by the slightest physical impact
Have such a low electrical resistance that the current can flow from the output to the input of the charging station

The best insulation suitable for this is PVC. This is tough enough to withstand the weather conditions outside for a relatively long time.

Although silicone is even more resistant to chemical weathering processes, it is damaged by even the smallest physical impact, such as stones in the ground along which the cable rubs.

Even small cracks in the insulation can cause the cable to rust through after a very short time. Therefore, the insulation material must be of a reasonably robust material.

The electrical resistance of the cable is determined by the material with which the cable is made, as well as the thickness of the cable. The longer the cable, the greater the resistance. It adds up over the length of the cable, so to speak.

For example, silver has a very good conductivity. However, since it is a very expensive material, it is not used very often. Copper, which is much cheaper than silver, conducts almost as well. Other metals like aluminium or zinc also have good conductivity. Only metals or alloys that have good conductivity properties are used in electrical cables.

What Are the Alternatives to the Original Boundary Wire?

The best way to compare prices between cables is to look at the price per foot. For the original cable of your robotic mower, simply divide the price in dollars by the length in feet to get the price per foot.

Values between $0.40/ft and $1.00/ft are usually obtained. Here are the alternatives:

Single Conductor

This is a very simple, PVC isolated single wire cable. This cable is also called a control cabinet cable. These cables are available in different thicknesses. With 1.5 mm² thickness you can’t go wrong.

You can find such cables in every hardware store and at various online retailers. They usually retail at around $0.14/ft. This is a much alternative than the original cables.

The cable is available in flexible and rigid versions. But which one should you use? The rigid wire has the advantage of being a little more corrosion-resistant, but they are not so good for “crimping,” which is the principle on which the cable connectors work. Small teeth press themselves into the metal surface of the cable.

This means that rigid cables will corrode slightly less, but may have major problems with the cable connectors. They are also harder to lay than flexible cables. I would therefore advise that you use flexible cables.

Field Telephone Wire

Another alternative to the typical boundary wire is Field Telephone Wire, which you might also see labeled as “DR-8-B Wire” or just “Field Wire.” These are cables that are laid out, used, and rolled up again in military operations. After being retired from military use, they are then sold in large quantities and bought up by resourceful dealers.

They then resell the cables at very reasonable prices. There are usually many listings for this wire on eBay, where you can find it as low as $0.08/ft, or perhaps even lower, which is of course much cheaper than the original cables.

While there is not much long-term experience with using these cables as boundary and guide wires for robotic mowers, it seems to work well.Since the cables are used by the military, a certain robustness and weather resistance can be assumed. But how long they can withstand the permanent weather conditions in your garden is unfortunately not yet clear.

If you are a person who likes to experiment, this can definitely be another cheap alternative.

Comparison of Alternative Cables and Original Cables

So is it worthwhile to switch to cheaper alternatives instead of the expensive original cables? This question is unfortunately not so easy to answer, as there are very different opinions on this. While some people have had very good experiences with alternative cables, others think that they will become obsolete after a shorter time.

Eventually you’ll just have to take some chances here. Since I’m personally quite an experimental person, I’d definitely try the cheaper versions.

Original cables have the advantage that they are definitely made for the weather conditions in the yard and can last for many years if they are not accidentally damaged. In addition, they come in a color that is not so noticeable in the lawn.

Alternative cables are available in all imaginable colors, red, yellow, (light) green, blue, brown, black, purple. Unfortunately, they are rarely available in the shade of green that would blend in well with the lawn. But, they are much cheaper.

While many robotic mower owners have already had very good experiences with the H07V-U, for example, there are also some dissenting voices who claim that such cables would rot somewhat faster.

In addition, alternative cables have the advantage that they sometimes come in much longer lengths than boundary cables, which you have to extend over long distances with cable connectors. Cable connectors offer a certain, albeit small, problem potential.

Unfortunately, even with alternative cables I have no personal experience that I could share with you.

If you want to save on the boundary wire, in my opinion the Field Telephone Wire is the best alternative.

There Are Also Alternatives for Cable Connectors

There are also all kinds of creative alternatives for cable connectors. Instead of the standard cable connectors, for example, so-called “butt connectors with shrink tubing” or “end connectors with shrink tubing” are used.

Also so-called Scotchlok cable connectors can be used. These work very similarly to the typical robotic mower cable connectors, but are much cheaper.

Cable connectors offer a certain potential for problems. For some, they do not cause problems for a long time. However, water can sometimes seep through the cable connectors and cause the cables to rust.

That is why some rely on the combination of shrink tubing + hot melt adhesive. By the way, a heat shrinkable tube is a tube made of a special plastic that shrinks when exposed to heat. It is used to electrically insulate material inserted into the cable. As a result of the contraction, almost no liquid can penetrate. Hot-melt adhesive then provides additional protection.