Outage causes
Outages can happen for many reasons — and when your lights go out, you want to know why.
Understanding the common reasons behind outages can help you stay informed and prepared. Read on to learn about some of the most common causes of outages.
Adverse weather
Ottawa’s weather can be beautiful, but it can also be tough on power lines. Extreme conditions are a leading cause of outages, including:
High winds
Strong winds can snap branches, topple trees and break power poles. This can damage overhead power lines, leading to widespread outages.
Lightning
Direct lightning strikes to power lines, poles and equipment can damage infrastructure and cause outages. Lightning can also induce power surges that trip safety equipment.
Ice, snow and rain
Freezing rain and heavy snow can accumulate on power lines, weighing them down until they break. The added weight can also bring down tree limbs onto lines.
Heat waves
While less common, extreme heat can sometimes stress electrical equipment, leading to malfunctions and outages.
Environmental factors
Factors in the environment can also impact your power supply, including:
Road salt spray
In winter, salt spray from roads can accumulate on electrical equipment, leading to corrosion and short circuits.
Humidity
High humidity can affect the insulation of electrical components.
Corrosion
The metal parts of our infrastructure can corrode over time, causing them to fail.
Vibration
Constant vibrations, such as from heavy traffic or nearby construction, can sometimes stress components and connections, leading to wear and tear.
Fire
Nearby fires can damage overhead lines and equipment, causing outages.
Flooding
Flooding can submerge underground equipment and even damage above-ground infrastructure, leading to power loss.
Defective equipment
Like any complex system, the equipment that delivers electricity to your home can sometimes fail because of:
Aging infrastructure
Over time, components like transformers, power poles and underground cables can degrade and fail. We continually inspect and upgrade our system to prevent this.
Equipment malfunctions
Sometimes, even new equipment can experience an unexpected defect or malfunction that leads to an outage.
Foreign interference
Outages can sometimes be caused by external factors that disrupt our electrical system, including:
Vehicle accidents
Vehicle collisions with power poles or other electrical equipment can cause immediate outages.
Animal interference
Curious animals, especially squirrels and raccoons, can come into contact with electrical equipment and cause a short circuit. This is often more disruptive for the animal than for your power supply, but it can still trip safety systems and cause an outage.
Excavation damage
Underground cables can be damaged by excavation work (like digging for a new fence or garden). Always remember to call before you dig to prevent accidental damage to underground utilities.
Third-party damage
Construction accidents or vandalism can damage electrical infrastructure and lead to outages.
Loss of supply
While rare, a power outage in your home can sometimes be due to an issue with the broader electricity grid that supplies Hydro Ottawa. For example, problems occasionally occur with Hydro One’s transmission system, preventing them from delivering power to us from the provincial grid. This results in outages for our customers.
Planned outages
Not all outages are unexpected. Sometimes, we need to temporarily turn off power to perform essential work, including:
System upgrades and maintenance
To keep your power system reliable and safe, we sometimes need to de-energize lines for planned upgrades, repairs or maintenance.
New connections
When new homes or businesses are connected to the grid, or when existing services are significantly modified, a planned outage may be necessary to complete the work safely.
We always strive to inform you well in advance about any planned outages, so you can prepare.
Tree contacts
Trees are a vital part of Ottawa’s landscape, but they’re also a frequent cause of power interruptions. Tree-related issues include:
Branch contact
When branches grow too close to power lines, they can make contact during windy conditions, causing a short circuit and an outage.
Falling trees/limbs
During storms, trees or large limbs can fall directly onto power lines, breaking them and damaging equipment.
We regularly trim trees near power lines to minimize these issues, helping keep your power on.
Unknown causes
Occasionally, the initial cause of an outage isn't immediately clear. In such cases, our crews work diligently to patrol the affected area, investigate the system and find the cause so repairs can begin.
We track all power outages and their causes, which helps us determine where to invest in our power system. For example, if we find that trees are frequently coming into contact with our power lines, we’ll adjust and improve our tree-trimming programs.