Power quality
What you need to know
Power quality issues can affect your lights, appliances and equipment. Flickering lights and tripped breakers often signal a problem. While we work to maintain reliable electricity service, some issues still occur.
What is power quality?
Power quality refers to the stability of your electricity supply. Poor power quality can damage electronics and reduce your home’s energy efficiency.
Power quality problems may be triggered by:
Lightning strikes
Switching of large motors or machines
Overloaded or faulty circuits
Inadequate or improper wiring
How to spot power quality issues
You may be experiencing power quality problems if:
Lights flicker or dim frequently
Computers or electronics restart or shut off on their own
Circuit breakers trip for no clear reason
Automated systems stop working or behave unpredictably
If you notice any of these, report it to our Customer Service team.
Power quality investigations
We’ll investigate any reported power quality issue at your service connection. If the problem is traced to the electrical grid, we’ll take steps to fix it.
If the issue comes from inside your home or business, you must arrange repairs.
Voltage reduction tests
Ontario’s Independent Electricity System Operator (IESO) conducts routine system voltage reduction tests every 18 months. These tests help assess system reliability. They usually go unnoticed by electricity users. At most, you might see a slight dimming of lights during the test.
For more information about voltage reduction tests, visit the IESO website.
To report a disruption during voltage reduction testing, visit our Outage Centre, use our app, text “OUT” to PWROUT (797688) or call our outage line at (613) 738-0188.
How to prevent power quality problems
Proper electrical setup and maintenance can help you avoid power quality issues. Start by ensuring your wiring is correct and your system is properly grounded. Avoid overloading your circuits, as doing so can lead to voltage drops and equipment failure.
It’s also important to install surge protection or filtering devices if you're using sensitive equipment. If you generate your own power, ensure your system doesn’t interfere with the broader electricity grid.
Have more questions on power quality? Visit our FAQs page.
Special considerations for farms
If you suspect that high levels of stray voltage are affecting your farm, we’ll investigate the issue. Visit our farms page for more information.