Understanding the Ontario Electrical Safety Code on Aluminum Wiring

The ESA, and Ontario Electrical Safety Code (OESC) set firm standards for handling aluminum wiring in residential properties. While the code allows aluminum conductors in some applications, it prohibits their use in branch circuit wiring under 40 amps. Specifically, aluminum wiring smaller than #6 AWG is not permitted for residential branch circuits. Where aluminum is permitted, strict safety measures govern its installation and termination.

Many homes built before the 1980s still use aluminum branch circuit wiring.
As properties age and electrical loads increase, Aluminum Rewiring in Toronto and other surrounding areas has become a focused approach for maintaining compliance and avoiding future complications.

Overview of the Code’s Position on Aluminum Wiring

The OESC does not mandate removing aluminum wiring that meets code specifications, is installed properly and functioning without issue. However, any new work involving aluminum conductors—such as repairs, extensions, or modifications—must follow detailed guidelines. Rule 12-118(1) of the OESC requires all terminations of aluminum conductors to be compatible with aluminum. Only connectors rated for aluminum should be used, and antioxidant compounds must be applied where specified.

Electrical Safety Authority (ESA) Flash Notice 19-30-FL emphasizes that electrical contractors and homeowners must follow correct procedures when replacing aluminum wiring. This includes approved methods of connection and proper torque settings. Incorrect practices can lead to connection failure or overheating, increasing the likelihood of safety issues.

Key Regulations for Homeowners

Regulations outlined in the OESC address new installations and existing wiring modifications.

Key points include:

• All devices connected to aluminum wiring must be marked “CO/ALR” (Copper-Aluminum Revised). 
• Connections must be made using devices certified for aluminum use. 
• Any splicing or terminations require approved connectors rated for aluminum conductors. 
• Only licensed electrical contractors can carry out work involving aluminum branch wiring. 

Attempting DIY modifications without knowledge of these regulations can result in unsafe outcomes and void insurance claims in the event of electrical failure.

Implications of Non-Compliance while Replacing Aluminum Wiring

Non-compliance with the OESC can trigger several issues. The ESA has the authority to conduct inspections and issue deficiency notices for code violations. Insurance providers may deny coverage or increase premiums if aluminum wiring is found to be improperly modified. In worst-case scenarios, faulty connections from incompatible devices or incorrect materials may result in overheating or fire.

These risks make it necessary to stay within the OESC framework. Replacing Aluminum Wiring is not always required, but any work must reflect strict adherence to the code. Ignoring these standards can create long-term liability and increase repair costs.

Bringing Aluminum Wiring Up to Code

Homeowners considering renovations or additions must evaluate the condition and compatibility of their existing aluminum wiring. An inspection from a licensed electrical contractor will determine if the wiring is intact and whether terminations need upgrading.

Common compliance steps include:

• Replacing switches and outlets with CO/ALR-rated devices. 
• Inspecting all connections for corrosion or looseness. 
• Re-terminating or pig-tailing aluminum wires using approved methods. 
• Applying the antioxidant paste where required. 
• Verifying torque settings meet manufacturer specifications. 

Not every home requires Aluminum Wiring Replacement, but targeted updates and corrections can meet current safety standards. Proper documentation of the work performed also helps meet insurance and resale requirements.

Final Thoughts on Code Compliance

The Ontario Electrical Safety Code addresses the risks of outdated wiring while allowing for safe, regulated upgrades. Older, non-compliant, aluminum systems still exist in thousands of GTA homes.

Adhering to the guidelines protects property value and reduces electrical hazards. Hiring licensed electricians with experience in aluminum rewiring in Toronto helps maintain this balance by updating systems without unnecessary overhauls.

Book a code-compliant assessment or upgrade today with Canadian Wire Wizards. Request a qualified inspection or get started on Aluminum Wire Replacement with experienced hands.