What Causes a Blackout?

If the power goes out in your neighbourhood, you can lose access to heat, water, and light. But what causes power outages to occur in the first place? In this article, we’ll go over ten of the most common reasons for a blackout.

Planned outages

Planned outages occur when electric utilities need to perform maintenance or repairs on their equipment. These activities typically require large amounts of electricity, which can cause a spike in demand. This can lead to an unexpected outage if there aren’t enough generators available to meet the increased demand.

Poor weather

Poor weather is one of the most common causes of power outages because rain can cause trees to fall on power lines, and heavy winds can damage equipment. Lightning strikes can also cause power outages under certain circumstances, such as if lightning strikes a transformer or power line.

Fallen trees

When it comes to power outages, fallen trees are often to blame. The reason for this is that when a storm hits, trees can get uprooted or broken and can fall on power lines. When this happens, it can cause a power outage for all or part of a neighbourhood.

Animal interference

Animal interference is another common cause of power outages. While squirrels and birds are not the largest animals that can cause power outages, they are some of the most common. Squirrels are notorious for chewing through electrical wires and causing fires. Birds can also create problems when they build nests on electrical equipment or use them as perches, which can cause short circuits and failures.

Vehicle crashes

Vehicles crashing into substations are also a significant cause of power outages. When a car hits a substation, it can cause an explosion that damages equipment and starts a fire. These types of power outages often take a long time to repair.

Construction or maintenance work

Construction activities such as digging, trenching and backfilling can damage underground electric lines. The damage may not be immediately noticed by construction crews and may not even be visible to utility crews until they attempt to restore power after an outage.

High energy demand

Another possible reason for power outages is a sudden increase in energy demand. An increase in energy demand can cause overloading of the distribution system, which can result in blackouts occasionally. This is rare, but it happens.

Equipment failure

Equipment failure often causes power outages. Equipment can fail for any number of reasons, but the most common are lightning strikes, tree branches and birds that come into contact with power lines.

Bushfires and natural disasters

Bushfires and natural disasters can cause a power outage. This can happen when trees or other vegetation come into contact with overhead power lines or when bushfires damage poles and substations.


Vandalism can cause a power outage in a number of ways. For example, if someone breaks a power line, it could cause a fire and subsequent outage. Vandalism can also result in damage to equipment that leads to disruptions in service. Sometimes vandalism is deliberate, but other times it’s accidental. For example, if someone accidentally knocks down a power line with their car or by falling from a ladder, it can cause damage and an outage.


There are many reasons for why the power could go down in your home. However, the most common reasons are usually weather related. Therefore, if you expect a big storm to roll through, then be sure to call a licensed electrician to help prepare your home during a blackout.

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