Solar interconnection in Ontario is the process of getting your home solar system approved to connect to the grid through your local distribution company (LDC), the utility that delivers your electricity, such as Hydro One, Toronto Hydro or Alectra. It involves three players: your LDC, the Electrical Safety Authority (ESA) and, for most rooftop systems, your municipal building department. Once you’re connected, Ontario’s net metering rules let you earn bill credits for the surplus power you send to the grid.
Who handles solar interconnection in Ontario
Organization
Role in your solar project
Your local distribution company (LDC)
Reviews your connection application, sets technical conditions, installs or reprograms the meter and manages net metering credits
Electrical Safety Authority (ESA)
Receives the electrical notification of work, inspects the installation and issues a Connection Authorization to your LDC
Your municipality
Issues the building permit for rooftop arrays of 5 m² or more, and checks zoning or heritage rules
Your installer
Usually coordinates all of the above for you
Step 1: Talk to your LDC early
Each LDC has its own application forms and technical requirements. Your installer should confirm early whether the local grid can accept a new generator at your address, especially in neighbourhoods that already have a lot of solar.
Small residential systems usually follow a simpler process. Larger systems may need a connection impact assessment: a study of how the system will affect the local grid, which adds time and cost.
Step 2: Submit the connection and net metering application
Your installer normally submits the application on your behalf, with the system size, a single-line electrical diagram and the equipment specifications. The LDC reviews it and approves the connection, sometimes with conditions. Our guide to solar approval documents explains each document.
Step 3: Get your building permit
In Ontario, a building permit is required for solar collectors mounted on a building with a face area of 5 m² or more, which covers almost every home rooftop array. The design and on-site review must be done by a professional engineer licensed in Ontario. See the City of Ottawa’s solar collector permit page and the City of Toronto’s solar collector guide.
Step 4: File with ESA, install and inspect
Before electrical work starts, a notification of work, which is the permit, must be filed with ESA. This is usually done by a licensed electrical contractor. After installation, ESA inspects the work. When it passes, ESA issues a Connection Authorization to your LDC. The LDC won’t connect your system without it.
Step 5: Meter, agreement and credits
The LDC installs or reprograms a meter that records electricity in both directions and confirms your net metering arrangement. Ontario’s net metering rules are set out in O. Reg. 541/05. Under net metering:
surplus electricity you send to the grid earns credits on your bill
credits offset the electricity you draw from the grid later
unused credits carry forward only for a limited period, so ask your LDC how it applies the rule
In 2022, Ontario amended the regulation to clarify that third-party ownership arrangements, such as leased systems, can take part in net metering.
How long does solar interconnection in Ontario take?
Timing depends on your LDC’s workload, whether a connection impact assessment is needed, building permit review times and inspection scheduling. Spring and summer are the busiest seasons. Ask your installer how long recent projects with your LDC have taken, and see our solar installation timeline.
Common delays and how to avoid them
Most delays in solar interconnection in Ontario come from a handful of avoidable issues:
Incomplete applications: make sure the diagram and equipment list match the final design.
Equipment changes: if the inverter or panels change after approval, tell the LDC before installing.
Late inspections: book the ESA inspection as soon as the work is finished.
Local grid limits: ask about capacity before you sign, especially in busy solar areas.
Switching on early: never operate the system for export before the LDC confirms you can.
Solar interconnection in Ontario runs through your LDC, ESA and, for most rooftop systems, a building permit. Choose an installer who works with your LDC regularly, keep copies of each approval, and wait for the LDC’s go-ahead before turning the system on.
Frequently asked questions
Do I need ESA approval for solar panels in Ontario?
Yes. A notification of work must be filed with ESA, and the installation must pass inspection. ESA then sends a Connection Authorization to your local utility.
Is net metering available in Ontario?
Yes. Ontario’s net metering regulation lets eligible customers earn bill credits for surplus renewable electricity sent to the grid. Contact your local distribution company for its application process.
Do I need a building permit for solar panels in Ontario?
For rooftop solar collectors with a face area of 5 m² or more, yes, with an engineered design. That covers almost every home rooftop system.
