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Reasons for Power Outages

Illustration of reasons for power outages in GuelphPower outages can be caused by the upstream loss of the electricity supply to our community, equipment failure, weather conditions, tree contact, wildlife interference, or vehicle accidents.

View our infographic to learn more about the most common reasons for power outages in Guelph. 

Wildlife is the Leading Cause of Power Outages in Guelph ... and North America

Squirrels and birds coming in contact with power lines and transformers cause brief power interruptions for Guelph Hydro customers. Animal contact with electrical apparatus is not unusual. In fact, squirrels are among the most frequent causes of power outages across North America. Here in Guelph, wildlife interference accounts for almost half of the power outages experienced by customers. These sorts of power outages take place most often in June, July and August when animals are most active.

How Animals Cause Power Outages

When squirrels, raccoons, birds, mice or snakes are electrocuted as a result of coming into contact with energized electrical equipment, circuit breakers or other protective equipment shut off the flow of power to protect the electricity system—similar to the way in which a breaker works in a home electrical panel.

In order to keep power outages to a minimum, these circuit breakers attempt to reset automatically, within a fraction of a second of the start of the outage. If the animal is no longer in contact with the equipment, power starts flowing again and customers will have experienced only a momentary outage or “blip” in their electricity service. Although only lasting a fraction of a second, these brief outages will often result in customers having to reset clocks or other sensitive electronic equipment.

If the circuit breaker is unable to reset due to continued interference on the line, power is interrupted until Guelph Hydro crews arrive on scene to remove the animal, repair any damaged equipment and restore power.

Guelph Hydro’s 54,000 customers are served by about 60 high voltage feeder lines that run from transformer stations across more than 1,000 kilometres of overhead and underground lines to customer homes and businesses. Each feeder line provides electricity to thousands of customers.

An animal coming into contact with a piece of energized electrical equipment anywhere along a feeder line can result in customers all along that line experiencing either a brief power interruption lasting only a fraction of a second or a longer outage while crews make repairs.

Preventing Animal Contact with Electrical Equipment

Guelph Hydro investigates and carefully analyzes the root cause of all power outages. This information is used in determining how to best maintain and cost-effectively upgrade the electricity distribution system to deliver electricity to customers in Guelph and Rockwood as reliably as possible.

Over the last few years, Guelph Hydro’s program for reducing the number of outages caused by wildlife interference has included:

  • Installing longer insulators on power lines, which reduces the likelihood of animals being electrocuted by touching the pole and power line at the same time
  • Replacing steel equipment, such as cross arms and brackets on power line poles, with non-conducting fiberglass equipment
  • Installing wildlife protection covers and insulated wires on all transformers to minimize the chance of animal contact
  • Preventing squirrels and other wildlife from scampering across power lines or climbing poles by installing wildlife protectors on overhead power lines and poles in areas where there are large trees
  • Diligent tree-trimming to limit animal access to power lines

Many outages can be rectified using remotely operated switches. If this is not possible, Guelph Hydro emergency crews are deployed rapidly to make repairs and restore power to customers as swiftly as possible.


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