Momentary outages

What momentary outages are and why they happen.

We understand outages, even short ones, can be an inconvenience. While we’re continuously working to help improve grid reliability, momentary outages can happen from time to time. They’re often due to extreme weather or trees and animals making contact with our equipment.

Note: Momentary outages should only be reported if they occur frequently over a short period of time. We encourage customers to read further to understand why these outages happen and if they require further investigation.

What are momentary outages?

Short duration and momentary power outages can last anywhere from seconds to a few minutes. They occur when there is a fault – an interruption in the flow of electricity – on our lines, usually due to external causes. Some common causes for momentary outages include:

Weather events, such as lightning strikes or heavy rain, can impact our equipment. High winds can also cause tree branches to touch our lines, or our lines to come in contact with each other.

Toronto is home to a large tree canopy and wildlife population. Because our lines can run for several kilometres near the city's many trees, it’s not unusual to see momentary outages caused by branches or animals, like squirrels, making contact with our lines.

The build-up of winter road salt or environmental pollution like dust and pollen on our equipment could cause momentary outages.

Much like a circuit breaker in your home, when our system detects a fault on the lines, the breaker trips the power to this area to help prevent further damage to our equipment. The breaker will then try to reset to minimize the outage duration.

If the cause of the fault (such as a tree branch) has cleared the line, the power is fully restored. If the breaker can’t reset automatically, our Control Room staff may try to reset it remotely to restore power. This may take a few extra minutes to do. This is a normal part of how an electrical distribution system operates and helps to prevent longer outages.

What we’re doing to address frequent momentary outages

While momentary outages are part of a normal electrical distribution system, we’re continuously monitoring our system for abnormal activity. If we identify cases where customers may be experiencing multiple brief outages over a short time period, we investigate. Our crews and engineers work together to troubleshoot the issues and help prevent them from occurring again.

If we identify frequent momentary outages, we take the following steps:

  1. Analyze the outages

    Our crews and engineers review the frequency, duration and causes of the outages to determine next steps.

  2. Patrol the lines

    Crews patrol the electrical distribution lines to identify potential problems (e.g. overgrown trees) and determine ways to help solve the issues.

  3. Outage mitigation

    Once we identify potential causes of the frequent momentary outages, our crews and engineers work together to help solve the issues. This could include tree-trimming, removing contamination from equipment caused by environmental issue or even making repairs and replacing equipment.

We’re also taking proactive steps to continue to improve power quality:

We actively monitor our electrical system year-round and analyze power interruption trends to help improve service across the city. Our crews, control room staff and engineers work together to proactively identify and troubleshoot issues.

Depending on what's required, our crews perform proactive maintenance to help reduce momentary outages. This can include:

  • Regular tree trimming
  • Washing overhead equipment
  • Regular line patrols and inspections of underground equipment

While we do our best to prevent interruptions to customers, sometimes unexpected outages happen. We’re continually investing in our grid to renew aging infrastructure, keep up with a growing city, and address reliability, safety and customer needs.

Frequently asked questions

Sometimes, momentary outages may occur repeatedly because they’re often caused by external factors, which can be hard to identify. If we see a high frequency of momentary outages, we often send a crew to patrol the lines and investigate potential issues. Unfortunately, it can be difficult to pinpoint the exact reason for a momentary outage because the cause typically clears the line quickly.

For example, winds may bring a tree branch onto an overhead wire before falling to the ground. However, by the time our crews arrive on site to investigate, the branch may not be on the wire anymore.

Toronto’s electrical system is complex, which means that in some cases your neighbours may be fed from different electrical equipment than your home. That means any outages or issues you may experience can be different from your neighbours.

Unfortunately, momentary outages can disrupt sensitive digital equipment in your home, like digital adapters and microwaves. To help protect your equipment, you may consider using surge protectors, which are devices designed to protect electrical devices from voltage spikes.

Note: If you’re experiencing flickering lights, partial power or other outage-related issues, report online or call 416-542-8000 (press 1).

Customers should only report momentary outages if they happen frequently over a short period of time. If you have any questions or concerns about momentary outages you may be experiencing, please call us at 416-542-8000 (press 5) from Monday to Friday, 8 a.m. to 8 p.m.