Power quality for your business
What you need to know
Power quality issues can disrupt your business operations. While we work to maintain a stable and reliable electricity grid, some disturbances still occur, often due to factors beyond our control. Learn more about power quality, how we investigate problems, what you can do to protect your equipment, and how to identify and report issues to us.
What is power quality?
Power quality refers to the stability and consistency of your electricity supply. It includes your service entrance’s voltage levels, voltage distortion and current distortion. Poor power quality can cause malfunctions in sensitive equipment, unscheduled shutdowns and even long-term equipment damage.
Common causes of power quality issues
Power quality issues may be caused by:
- Lightning strikes or severe weather
- Switching of large motors or heavy machinery
- Circuit overloadsImproper wiring or grounding
- Starting current surges from large motors
- Faults on the customer side of the connection
These events may result in voltage dips, brief outages or performance issues with automation and control systems.
Power quality investigations
To investigate power quality concerns, we’ll measure the conditions at your service entrance. We follow the industry standards outlined in our technical guidelines.
If the problem stems from our distribution system and falls outside acceptable limits, we’ll take the necessary steps to fix it. If your facility or equipment caused the issue, you’ll be responsible for addressing it.
How to spot power quality issues
You may be experiencing a power quality issue if:
- Lights frequently dim or flicker
- Computer systems reboot unexpectedly
- Equipment behaves unpredictably or malfunctions
- Circuit breakers trip without an obvious overload
- Automated systems stop working or behave unpredictably
If you notice any of these, report it to our Customer Service team.
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 our customers. At most, your lights may dim during the test.
For more information about voltage reduction tests, visit the IESO website.
To report a disruption during voltage reduction testing, visit our Report an outage page, use our app, text “OUT” to PWROUT (797688) or call our outage line at (613) 738-0188.
How to prevent power quality problems
You can reduce power quality risks at your business by:
- Ensuring your business is wired and grounded properly
- Avoiding overloaded circuits
- Installing surge protection and filtering devices
- Maintaining acceptable startup loads for large motors
- Separating lighting and sensitive equipment from heavy motor loads
If your facility operates a distributed energy resource or uses large, non-uniform loads, you must ensure these do not affect the distribution system. This may require protective equipment or modifications.
Special considerations for farms
If you suspect that high levels of stray voltage (also known as "tingle voltage") are affecting your farm, we’ll investigate the issue. Visit our farms page for more information.