Can I Add a Subpanel Myself?

Can I Add a Subpanel Myself?

In Ontario, adding a subpanel is regulated electrical work that requires an ESA permit and must be performed by a Licensed Electrical Contractor. A homeowner cannot legally install a subpanel on their own property in Ontario — even as the property owner. The work involves working inside the main panel with the service energized, running a feeder circuit, and sizing the subpanel and its breakers correctly for the application.

What a Subpanel Installation Involves

• Determining the correct subpanel amperage based on the anticipated load
• Sizing the feeder wire (typically 6 AWG for 60A, 4 AWG for 100A) and breaker in the main panel
• Running conduit or cable from the main panel to the subpanel location
• Separating the neutral and ground bars inside the subpanel (required in all detached structures)
• Installing a main breaker in the subpanel if it is in a separate building
• Pulling an ESA permit and having the work inspected

The Neutral-Ground Separation Rule

One of the most commonly missed requirements in subpanel work is the neutral-ground separation. In the main panel, neutral and ground are bonded together. In a subpanel, they must be kept separate — the ground is connected to the grounding electrode at the subpanel location, while the neutral runs back to the main panel unbonded. This is critical for shock protection and correct operation of GFCI and AFCI devices. Homeowners doing DIY subpanel work frequently get this wrong.

Detached Structures

Subpanels in detached garages, workshops, or outbuildings have additional requirements under the Ontario Electrical Safety Code. A separate grounding electrode (ground rod or plate) must be installed at the detached structure. A main disconnect must be provided. These requirements are beyond what most homeowners are familiar with.

EZSMART installs subpanels for garages, workshops, additions, and home expansions across Ontario. Contact us to get your project quoted and permitted properly.

Amir Azimipour

Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp