What Causes a Short Circuit

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Written by Tristan Cameron

What causes a short circuit is something every Australian should know and be prepared for. They’re extremely common, especially in some of the ageing properties in our cities.

A short circuit can happen for many reasons, most of which are tied back to issues with the wiring in your home. 

Here’s our complete guide on a short circuit, what causes it, and how to prevent and fix it. 

What is a Short Circuit?

Electricity is supposed to flow in one direction, from the source (the switchboard) to its destination, usually lights or an appliance. If something happens — usually with the wiring — it stops its journey sooner than planned and tries to find a place to ‘earth.’ 

In our homes, this happens in the form of a leak, and the electricity has jumped its path, and it’s looking for the nearest source to land. Unfortunately, sometimes the landing place is someone unknowingly touching the closest appliance or powerpoint to the leak. This could result in an electric shock, which can be devastating. 

Types of Short Circuit

There are two types of short circuits: the traditional one and one referred to as a ground fault.

Regular Short Circuit

The most common type of short circuit happens when a hot live wire connects with a neutral one. The resistance decreases immediately, but simultaneously, a surge of electricity will flow in the wrong direction. This type of short circuit can result in crackling noises, sparks, or even an electrical fire.

Ground Fault

When a hot live wire connects with the ground part of the system, it’s referred to as a ground fault. Similarly, the resistance decreases, and electricity flows in the wrong direction. While a fire isn’t likely, a ground fault is what delivers an electric shock when it comes into contact with a person.

The Causes of a Short Circuit

There are three primary causes of a short circuit, and they all have to do with wiring. Many Sydney homes have old wiring, wear and tear, and erosion comes with age. People who live in homes where the wiring hasn’t been updated in over 30 years are most at risk and need to be aware of the following:

Insulation Covering the Wiring

The wires that carry the electricity from the switchboard are covered in insulation. Over time, this insulation wears away. 

If the house’s walls aren’t insulated properly, the humidity can build up, damaging the wire covering. Any DIY work done on the home could accidentally put nails or screws through the casing too. Finally, rodent infestations in many Sydney homes can also lead to them chewing through the insulation.

Once the insulation wears away, the wires risk being exposed. Wires in this condition are more likely to result in a short circuit.

Loose Wiring

With wear and tear, wires can become loose; if this happens, the live and the neutral wires can connect, resulting in sparking, excess heat, and possible ignition. This issue is especially dangerous if the connection to the circuits in the switchboard comes loose. If your switchboard is over 30 years old, it needs an urgent upgrade to avoid this happening.

Faulty Appliances

Many short circuits happen as a result of faulty wiring of an appliance. Older devices and ones that are frequently used tend to wear out the wiring faster than others, which puts pressure on the circuits as they drain more power than they can use.

How to Prevent a Short Circuit

Modern switchboards already have safeguards against short circuits, but older homes are at risk. Here are two ways to prevent a short circuit:

Circuit Breakers

Circuit breaker panels are replacing old fuse boxes in Australian homes. The circuit breaker does as the name suggests; if it identifies a surge in electricity, it ‘breaks’ the charge immediately. 

Ground Fault Circuit Interrupters

Like a circuit breaker, these identify electrical surges caused by ground faults. The advantage over standard circuit breakers is that they’re sensitive and react faster, reducing the likelihood of an electric shock.

Repairing a Short Circuit

If a short circuit happens in your home, call us at North Shore Electricians immediately. We can fix the problem and identify if there is an underlying issue that could result in more of them occurring. 

These are the steps that we’ll take to solve the problem. We don’t recommend you attempt any of these as working with electricity, especially when it’s at fault, is dangerous.

  1. First, we’ll locate your circuit panel and inspect the switches; the one that identified the short circuit should already be in the off position. It remains off for now.
  1. Next, we’ll check every appliance that’s connected to powerpoints connected to that circuit. We’ll remove every one of them from their power sources. It’s highly likely that the one that caused the short circuit has melted insulation in the power cord. 
  1. Now we’ll flick the switch back to on; if it doesn’t automatically switch back to off (break), then it means we’ve identified that an appliance caused the short circuit.
  1. We now need to determine if there’s another appliance almost ready to short out. We’ll plug them in one by one, using insulated gloves to avoid a shock. If they all plug back in without issues, your system works properly. 

If the circuit breaker switches back to off at any time that indicates there’s an underlying issue with your house’s wiring. We may even need to do a complete rewire of the house to avoid further problems.

Any homes that are over 30 years old should undergo a full electrical inspection to be sure that issues like short circuits aren’t waiting to happen. Call North Shore Electricians today so we can assure you that your home is safe for you and your family.

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