You have probably heard the "tick - tick" of electric fences on your telephone from time to time. It is usually not too annoying on a phone call, but those "ticks" can be totally disruptive for fax and data calls.
Modern data transmission systems are particularly sensitive to line noise. Unlike the human ear, which is able to select the speech signal from any background noise, data systems detect such noises as errors, either slowing down the data speed or completely disrupting a call.
Electric fencing problems
One of the most common causes of interference to telephone and data services in rural areas is electric fencing, especially systems that have faulty electrical joints, are not earthed or insulated properly, and run in parallel with telephone cables.
In such cases, the fence system is not working at full efficiency and needs a bit of attention. Even more importantly, it could be disrupting telephone and data services for you and any of the other people served by a nearby telephone cable.
Fixing some of the causes may not be complicated or expensive - just a case of knowing what to do or not do!
Cable Location
Cables running through your property may have marker posts to show where they have been laid. On the other hand, such markers may not have been used or may have become overgrown or lost.
If you think there are cables running through your rural property, check with Telecom's Cable Location Service by dialling "124". They will be able to send you a free aerial photograph, which should show the location of any telephone cables on or nearby your property.
PLEASE - be aware of the problems that can be caused by electric fences and think of your neighbours. They may be affected even when you have no problems yourself!
Telecom will do its best to locate the source of problems caused by electric fences, but we NEED your co-operation in making any improvements.
Working near cables
If you plan any digging or excavation work where a cable is likely to be laid, call Telecom on 124. But please do this at LEAST 24 hours before you actually start the work.
This will help us to help you avoid possibly disrupting not only your own telephone and data services, but also the services we provide to your neighbours and other people served by the cable concerned.
Some general principles to follow:-
| DO | Install an adequate earth system for your electric fence energiser, and keep the soil around it moist. |
| Ensure good electrical connections along the fence conductors. Join energised wires with figure of 8 or reef knots, or use joint clamps for permanent connections. Check all connections at least once a year. | |
| Use good quality insulators for the energised wires, such as porcelain or Glass Reinforced Plastic. (GRP). Polythene pipe insulators don't work very well for very long. | |
| Use a modern electric fence energiser complying with AS/NZS 1044. Units made before 1988 are more likely to cause problems to telecommunications services. | |
| Use one wire of a fence as the ground return if you have dry or stony soil for most of the year. |
| DON'T | Install the earth system closer than 10 metres to telephone cables or other electrical earths. This includes metal water pipes used for electrical earths. |
| Run energised wires close to telephone cables for long distances. If possible, arrange your fence so that the power source is at the end furthest from any telephone cables. | |
| Run electric fences parallel to telephone cables over long distances. | |
| Allow undergrowth or loose wires to make contact between the energised wires and earth. | |
| Skimp on your fence maintenance! |
Following these rules will mean that your electric fence will control stock more effectively, without causing interference to telephone services in the area.
For more information, follow the installation instructions and all recommendations of your energiser manufacturer, or see your local electric fence dealer for advice.
Failing reduction of interference from the fence, the best thing for the affected customer to do is to convert the premises wiring to Telecom's 2-wire standard. This offers improved performance in the presence of electrical noise.