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Common causes of power outages

What Causes Power Outages?

Toronto Hydro is the largest municipal electricity distribution company in Canada, distributing approximately 18 per cent of the electricity consumed in Ontario. Although we work hard to prevent them, outages do occur from time to time – often for reasons beyond our control.


Causes of Outages

Listed below are some of the most common causes of outages:

Severe Weather

  • High winds can bring down trees and branches onto power lines.
  • Lightning can strike equipment or cause trees to fall into power lines.
  • Winter storms can create freezing rain and heavy snow that cause damage to electrical equipment.
  • Heat waves can increase demand for electricity from air conditioning, which can overload the system.
  • Rain and flooding can damage overhead and underground equipment.

Other Outage Causes

  • Equipment failure can trigger an outage, even though we regularly maintain and update aging infrastructure.
  • Vehicle or construction accidents can knock down hydro poles or bring down lines.
  • Animals, like squirrels, birds and raccoons, can damage power lines and equipment.
  • Cable dig-ins can cause outages when construction crews accidentally hit a buried line while excavating.
  • Trees can come into contact with a power line if they are not trimmed properly.
  • Planned Outages are occasionally scheduled to allow our crews to safely do repair work, maintenance or upgrades on our equipment. We do our best to notify you in advance.

How We’re Investing in Toronto’s Future

See our plan to improve service reliability for our customers.


40% of Outages Are Due to Aging Equipment

Toronto Hydro has invested to maintain and repair existing equipment. But, much like a car as it ages, even with regular maintenance, at some point it’s time to replace it.

Find out how we’re improving service reliability to meet your future electricity needs. Read our plan here.