Electric Fence for Homes in Maputo: How It Works
An electric fence on top of a boundary wall is one of the most effective ways to stop an intruder before he reaches the house. It works by sending short pulses along tensioned wires, raising an alarm the moment a wire is cut, shorted or touched to the ground. This guide explains how a residential fence works in Maputo and Matola, what it is made of, how it stays safe, and what decides the cost of a project.
How an electric fence works
The heart of the system is the energiser, a box mounted in a protected spot near the gate or the house. Roughly once a second it sends a pulse along the wires. The pulse is high voltage but very low energy and lasts a fraction of a second, so a person who touches a wire gets a sharp, memorable shock and lets go. That is the point: the fence deters and warns, it is not designed to injure.
At the same time, the energiser watches the line. If a wire is cut, if two wires are pushed together, or if the voltage falls because something is earthing the fence, it raises the alarm: a siren on site, and an alert to your phone or alarm panel. Many burglaries in Maputo start over the back wall at night, which is exactly where a fence gives the earliest warning.
What the fence is made of
- Energiser: we supply and install NEMTEK energisers, a South African brand made for these conditions. Models differ in power, number of zones and connectivity.
- Wires (strands): usually four to eight strands of high-tensile wire along the top of the wall, alternating live and earth so that cutting or bridging them triggers the alarm.
- Brackets and insulators: angled or straight brackets bolted to the wall hold the wires, and insulators keep them from touching the brackets.
- Earth system: earth spikes driven into the ground. A weak earth is the most common cause of a fence that does not bite or does not report faults.
- Siren, strobe and battery: the battery keeps the fence alive through power cuts; the siren tells the whole street.
- Warning signs: yellow warning boards along the fence, visible from both sides.
Is it safe for children, pets and neighbours?
A correctly installed fence follows the energiser standard for electric fences, which limits the energy of each pulse. The wires sit high on the wall, out of reach from the street, with warning signs at regular intervals. Children and pets inside the property are protected by the height, and gates get their own section so the gate motor and the fence do not interfere with each other.
What makes a fence dangerous is poor workmanship: wires too low, missing signs, a homemade energiser. That is the reason to use a recognised energiser and an installer who tests the line with a fence meter before handing over.
Living with an electric fence in Maputo
Three local habits keep a fence reliable.
- Trim the plants. Bougainvillea, palms and creepers grow fast in our climate. A branch resting on a live wire drains the voltage and causes false alarms. Keep a clear gap along the whole wall.
- Check after storms. Heavy rain and wind in the summer season can loosen wires or knock a branch onto the line. A quick walk around the wall the next morning saves a night of sirens.
- Plan for power cuts. The energiser battery keeps the fence working when the grid goes down. Ask how long it lasts and replace it before it ages out.
Fence, alarm and cameras together
The fence is the outer layer. Inside, a home alarm system protects the doors and windows, and cameras show what happened. When the fence zone is linked to the alarm panel and to the nearest camera, an alert on the back wall comes with the picture of the back wall, so you know at once whether it was a thief or a falling branch. Our page on intrusion alarm and perimeter protection shows the full picture, and the same layered approach protects the yards in our post on factories and warehouses in Matola.
What decides the cost of an electric fence
We do not publish prices, because every wall is different, but these are the factors in every quotation:
- the length of the perimeter in metres, including the gate sections;
- the number of strands and the type of brackets;
- whether the fence sits on a wall or is freestanding;
- the energiser model and the number of zones;
- links to the alarm panel, cameras or phone alerts;
- the state of the wall and any repairs before installation.
Frequently asked questions
Does an electric fence work during a power cut?
Yes, when the energiser has a backup battery. The battery powers the fence and its alarm through the cut and recharges when the power returns.
Will rain or plants set off false alarms?
Rain on its own does not, but plants touching the wires and a weak earth do. Keeping vegetation trimmed and the earth spikes in good condition prevents most false alarms.
Can the fence alert my phone?
Yes. With a connected energiser or a link to the alarm panel, you receive an alert when the fence is cut, shorted or switched off, wherever you are.
Can you install a fence on an existing wall?
Yes, in most cases. We check the wall during the free visit and tell you if any section needs repair before the brackets go on.
Get a free quote
Send us a photo of your wall and its approximate length, or book a free site visit in Maputo or Matola. Message us on WhatsApp +258 84 488 8222 or get a free quote.
Written by the A.S.S. LDA technical team, Maputo.