International Blog Is it possible to extend the perimeter wire or change it later?

Is it possible to extend the perimeter wire or change it later?

08.05.2021
The perimeter wire included in the delivery is no longer sufficient. Sometimes, due to changes in a garden design, new lawn areas are added or eliminated over time. In order for the robotic lawnmower to still be able to recognize all areas, it is necessary to adjust the perimeter wire. But is this possible?

The boundary wire generates a magnetic field that tells the robotic lawnmower which areas are to be mowed and which are not. In most cases, the delivery of your robot already includes a basic set of several hundred meters of perimeter wire, including lawn fasteners (nails). But what if these are not sufficient? What should you do if you change your garden layout or it increases in size over the years? In order to ensure your robot continues to function under these conditions, it is necessary to extend or modify the perimeter wire.

What is the perimeter wire used for?

Most robotic lawnmowers recognize the lawn area with the help of a perimeter wire. This is laid along the outer perimeter or your lawn, around beds, garden ponds or other areas that the robot shouldn’t drive over. By connecting the wire to the charging station, it creates a magnetic field that the robotic lawnmower detects and turns before crossing any boundaries.


At the same time, the wire helps the robot to find its charging station. When the battery is running low, it travels along the wire to the station. 
The perimeter wire is thus very important for the functionality of the robotic lawnmower. If the device does not detect the signal correctly, the robot will leave its area and cause damage to beds and the like. In the worst case, it can become damaged by falling into a garden pond or pool. 
Laying the cable is therefore the first task when activating a new lawn robot - and at the same time, the most time-consuming. After that, robot installation is usually quite quick and easy.

Extending the perimeter wire - this is how it's done

You can easily extend the perimeter wire if necessary. For this purpose, there are both butt and click connectors as well as special waterproof wire connectors. The latter ensure that moisture can’t penetrate or compromise a strong connection. Connections with an exposed screw run the risk of rusting. Therefore, in any case, use connections that can be squeezed with combination pliers.

Before getting started, lay out all the necessary tools:

  • Cable connectors
  • combination pliers
  • pliers or a knife to cut the cable 
  • a spade, if necessary (in case of underground laying)
  • additional lawn hooks (for above-ground installation)

Extending the perimeter wire step by step

  1. Disconnect the wire from the charging station to cut off the power supply. 
  2. Cut the perimeter wire at the point where the extension is to be inserted. Knives or pliers are suitable for this. 
  3. Insert one end of the existing wire into the connector and the new extension wire into the other end. 
  4. Squeez the connector together with combination pliers. 
  5. Repeat the procedure on the other end of the extension to close the circuit again.
  6. Reconnect the wire to the charging station and check the LED lights to see if a signal is being transmitted properly.
  7. Only when everything is working properly and any mistakes have been remedied, secure the extension with the turf hooks or bury the wire again.

Observe the maximum length of the perimeter wire

The maximum length of the boundary wire is finite. It can easily be seen in the instruction manual and sometimes differs significantly for robotic lawnmowers for areas for 300 m² or 2,000 m². On the one hand, this results from the fact that the robotic lawnmower can only cope with a certain area. On the other hand, the electrical resistance increases with the length of the boundary wire. This means that at some point, the signal can no longer be transmitted without error and interference can occur.

Extending the boundary wire above and below ground

If the boundary wire is above ground, the extension is quite simple. After testing the functionality, simply attach the additional route with lawn hooks as well. 
If the section is to be extended in the case of an underground cable, it is advisable not to bury the new section at first but to test the functionality while the robotic lawnmower is in operation. Adjustments can then be made easier before burying.

Repair broken cable

Small cracks lead to corrosion: the thatcher damages a cable or it is cut by a spade. There are many causes of damage to the perimeter wire. Most often they go unnoticed until the robotic lawnmower stops working properly.
A broken wire may cause errors in operation, and the search for it often proves tedious, as damage to the wire is not always easy to detect. A very simple method can make your search much easier.
If you do not have a special cable break detector on hand, an old transistor radio is also suitable. Switch the radio to a frequency without a transmitter, i.e. you should only hear a continuous hiss or a frequency tone. Then run the radio with the antenna parallel along the cable. At the point of a possible broken cable, the volume of the sound decreases significantly. The defective area can then easily be repaired using the method described above.

Which perimeter wire is suitable?

  • There are wires with different thicknesses. The thicker the wire, the lower the resistance. This is especially better for larger areas.
  • It is recommended to only use the wires produced by the manufacturer. They provide a signal optimally geared for the robot.
  • When extending the perimeter wire, the individual parts must match, i.e. the materials and the diameter as well as the resistance of the wire.

Criteria for selecting the perimeter wire

  • material of the insulating layer
  • thickness of the electrical conductor
  • single wire or twisted pair
  • additional protective layers, if necessary
  • flexibility
  • material of the electrical conductor
  • overall thickness of the cable 

For smooth functionality, it is also important to make sure that the cables are compatible with each other in terms of their properties. The extension of the perimeter wire will be simple and quick, and you will remain permanently flexible in garden design. Only the maximum length of the cable is a limitation of the extension.

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