How Do Multi-Zone Electric Fences Work?

How Do Multi-Zone Electric Fences Work?

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If you want to install an electric fence for security and you have a relatively long fence line, you probably need a multi-zone electric fence.

However, before you leap into getting quotes, you probably want to know what multi-zone electric fences are and how do multi-zone electric fences work? Here’s what you need to know.

What Makes an Electric Fence a Security Fence?

The first thing you need to know about how multi-zone electric fences work is what the difference between electric fences for security and electric fences for other purposes are.

When you install any electric fence energizer, you have a live out and a live return on the energizer.

In electric fences for agricultural use, the only real reason for the live and earth wires to return to the energiser is to complete the circuit. This is required to keep the current flowing through the fence.

However, in an electric security fence, the live and earth out and returns are also monitored – so when you have a short on the fence, you will get a signal that there’s a problem. On simple electric fences, this might be a strobe light or a siren. On more extensive, more complex, multi-zone fences, this is usually shown on the fence management software, which runs through a computer.

So, the difference between a regular electric fence and an electric security fence is that an electric security fence notifies you that there’s a short on the fence. These shorts could be anything from vegetation touching the fence to someone trying to climb it, but it tells you that there’s a problem on the fence line.

Why Do You Need a Multi-Zone Electric Fence?

If you have a long fence line around a site that needs to be secure, like a prison or military installation, just knowing that there is a short on the fence is not enough.

While most energisers can power many kilometres of wire, that’s not practical if your security team needs to go out and investigate a problem. Many high-security sites also have integrated perimeter security systems that include cameras and lights that can be operated from a guardhouse, so your team can look at the fence line without having to physically go to the fence.

However, this is only helpful if they know where the problem is.

A multi-zone electric fence breaks your fence line into shorter “chunks” so that your team knows where to focus their attention when something goes wrong. These “chunks” or zones are usually a couple of hundred meters, so there’s not too much fence to inspect when something goes wrong.

So really, the whole reason for a multi-zone electric fence is so that your security team can respond to possible problems as quickly as possible.

This is particularly important for sites like prisons or military bases, where any breach attempts are likely to be sophisticated operations, and action might need to be taken very quickly!

How Do Multi-Zone Electric Fences Work?

Now that you know what a multi-zone electric fence is and why you might need one, the next thing you need to understand is how they work.

Multi-zone electric fences use multiple different fence energizers to power the different zones of the fence. Each of those zones uses separate wires and operates independently of each other, so when there is a short or a breach of the fence, only that zone will report a problem.

Usually, these kinds of fences use what is known as dual-zone fence energizers. That means that they are energisers that can power the fence to the right and left of the installation position. They usually need to be powered by an underground cable that runs around the site's perimeter (often with a communications cable). They usually have backup batteries in case there is a power failure on the fence.

As you can see on our simple diagram of a fence line, these energisers are usually installed at the end of a fence line so that it’s easy to run and tension the wires for each zone. Often, as in our diagram, each gate is its own zone, so that you can get a special notification if there is a problem at one of the entrances to the site.

When someone or something touches the wires on a particular zone, the energizer registers the problem and sends a signal to the computer-based management system, displaying the problem on a map of the fence marked with the different zones. Your team can then either go to the zone to check on the problem or use lights and cameras from the guardhouse.

Many electric fence energizers that are used for security fencing require in-person resetting – so your security team can’t simply ignore the problem and reset it at the guardhouse – they have to be physically present on the affected zone.

All of the shorts and responses, and resets are recorded on the electric fence logs, too, so you can see what happened when it happened and how long it took to respond. These logs are an electronic record of everything that happens on the fence that can only be accessed by authorized people. So you can see exactly what happened on your fence throughout the time between viewing logs.

Important Things to Remember About Electric Fences

As you can see, multi-zone electric fences are a great way to protect and monitor large fence lines, but there are a few things you need to remember about electric fences to make them work at their best.

First, remember that anything that touches the fence can cause a short. Even vegetation that touches the fence line can cause shorts and false alarms. Many people choose to have a concrete pavement or strip along the fence to ensure plants can’t grow there. Other sites like prisons often opt for a stone layer that is treated with pesticide regularly.

Second, make sure that you inspect and maintain your fence regularly. Cracked insulators, wires that are touching and many other seemingly minor things can cause the fence to malfunction. Many people who have high security fence systems enter into maintenance contracts for this reason. A professional fence contractor will know exactly what to check and repair on your fence when they walk the fence line.

The next thing you need to know is that while zones usually monitor different parts of the fence line, they can also be configured in other ways. For instance, if you have electric fence wires on the body of a fence that you want off during the day but on at night, they could each be independent zones, running from a different energizer – or you could put both on one dual-zone energizer.

You also need to remember that electricity and water are not friends, so you need to ensure that your energizers on the fence line are installed in a weatherproof enclosure. Water in an energiser can cause shorts or even cause irreparable damage to your energizer.

An electric security fence is very different from the kind that is used for animals and other applications. You will definitely need to use a knowledgeable and experienced contractor to get one installed properly. So, make sure you factor all of that into your planning.