2025 Ontario Electrical Safety Code (29th Edition): Key Changes You Need to Know
The 2024 Ontario Electrical Safety Code (OESC), 29th edition, based on the 2024 Canadian Electrical Code (CSA C22.1:24), came into effect on May 1, 2025. It introduces significant changes to outdoor receptacles and ground fault protection, electric vehicle installations, energy storage systems, pool bonding, and more. Here's what every builder, contractor, and engineer needs to know.
What Changed and When
The OESC is Ontario's adoption of the Canadian Electrical Code with Ontario-specific amendments. The 29th Edition replaces the previous 28th Edition and applies to all new electrical installations and modifications permitted on or after May 1, 2025. Existing compliant installations are not required to be retroactively upgraded unless modifications are made.
1. AFCI protection (unchanged since 2015)
Combination-type Arc Fault Circuit Interrupter (AFCI) protection has applied broadly to dwelling units since the 2015 OESC. Combination-type AFCI protection under Rule 26-658 applies to branch circuits supplying 125 V receptacles rated 20 A or less in dwelling units, subject to listed exceptions. The table below summarizes the general scope of AFCI protection - verify specific room-by-room and circuit-by-circuit requirements against the full 2024 OESC and ESA technical bulletins for your project.
| Location | Previous Editions | 2024 OESC (29th Ed.) - Verify |
|---|---|---|
| Bedrooms | AFCI required | AFCI required - no change |
| Living rooms, dining rooms, dens | AFCI required | AFCI required - no change |
| Hallways, closets | AFCI required | AFCI required - no change |
| Kitchens (125 V receptacle circuits) | AFCI required where applicable | Verify Rule 26-658 against the exact receptacle and room layout; do not assume every lighting-only circuit is included |
| Recreation rooms, sunrooms | AFCI required | AFCI required - no change |
| Laundry rooms (120V) | AFCI required | AFCI required - no change |
| Bathrooms | GFCI only | GFCI only - no AFCI required |
| Garage (attached to the dwelling) | AFCI required | AFCI required - no change; GFCI not required inside a garage |
Important: The AFCI scope above has not changed since the 2015 edition. Always verify against the actual 2024 OESC rules (Rule 26-658 and related) and ESA bulletins before finalizing your design. Specific Ontario amendments may modify the CEC base requirements.
2. GFCI Protection Updates
Ground Fault Circuit Interrupter (GFCI) requirements have also been updated. The ESA has confirmed changes related to outdoor receptacles for single dwellings. The table below reflects the general scope of GFCI requirements - verify specific requirements against the full 2024 OESC and ESA bulletins.
| Location | What Changed - Verify Against OESC |
|---|---|
| Outdoor receptacles (single dwellings) | Confirmed by ESA: additional requirements for outdoor receptacles; 5-15R/5-20R receptacles outdoors within 2.5 m of grade need Class A GFCI protection (Rule 26-704 2)) |
| Bathrooms | GFCI required - no change (already required) |
| Garages / accessory buildings | No GFCI required for receptacles inside a garage under Rule 26-704; receptacles outdoors within 2.5 m of grade need GFCI |
| Kitchen / laundry / unfinished basements | GFCI applies to 5-15R/5-20R receptacles within 1.5 m of a sink, bathtub or shower (Rule 26-704) |
3. Electric Vehicle (EV) Infrastructure
The 29th Edition introduces important updates for EV Supply Equipment (EVSE) installations, reflecting Ontario's push toward electrified transportation.
- Revised demand load calculations - Rule 8-106 10) and 11) let an energy management system set the demand load for the loads it controls, making it easier to add EV chargers without oversizing the service
- Energy Management Systems (EMS) - the code now formally recognizes load management systems that can control EV charging demand, potentially eliminating the need for service upgrades
- Higher allowable voltages - certain EVSE installations may now operate at higher voltages, aligning with newer equipment standards
- Plan review requirements - certain EVSE installations trigger ESA plan review. See the current ESA Electrical Plan Review guide for the July 2026 12 kW threshold and submission requirements.
Note: Ontario Bill 52, the EV-Ready Homes Act (Electric Vehicle Charging), 2025, has been introduced and ordered for Second Reading, but has not yet been enacted into law as of May 2026. It would amend the Building Code Act to mandate EV-ready infrastructure in new homes. Meanwhile, the 2024 Ontario Building Code has no EV-ready requirement, and the Toronto Green Standard now lists its EV infrastructure measure as voluntary (some zoning by-laws still set EV-ready parking rules). The OESC governs the safety of EV installations regardless of building code mandates.
4. Energy Storage Systems (ESS)
With the growing adoption of residential battery systems (e.g., Tesla Powerwall, Enphase IQ), the code has completely rewritten installation requirements for battery-based energy storage systems in residential buildings.
- Rewritten requirements for ESS installations at residential occupancies
- Ventilation requirements - proper ventilation and temperature management for lithium-ion battery installations
- Labeling requirements - clear identification of ESS equipment, disconnects, and interconnection points
5. Pools, Hot Tubs, and Equipotential Bonding
Enhanced equipotential bonding requirements have been introduced for pools and hot tubs to further prevent shock hazards:
- Updated bonding grid requirements for in-ground pools
- Clearer specifications for bonding conductive pool shells, metal fittings, and surrounding metallic structures
6. Labeling and Panel Load Management
The 29th Edition introduces more specific requirements for circuit labeling and load management:
- Maximum load labeling - the code now requires labelling of the maximum residential load to prevent future overloading
What This Means for Your Project
| If You Are... | Action Required |
|---|---|
| Building a new home | Outdoor-receptacle and GFCI changes may affect the design, and combination AFCI protection already applies to most dwelling-unit receptacle circuits. Check municipal bylaws for EV-ready wiring requirements. |
| Renovating an existing home | Any new or modified circuits must comply with the 29th Edition. Existing compliant circuits are grandfathered. |
| Installing an EV charger | Use the revised demand-load rules (Rule 8-106 10) and 11)). Consider EMS for load management to avoid service upgrade costs. |
| Adding battery storage | Follow the completely rewritten ESS section. ESA plan review may be required. |
| A contractor or builder | Ensure your team is trained on the new requirements. Work notified (or plan-reviewed) on or after May 1, 2025 must comply with the 2024 OESC (29th Edition). |
ESA Resources
- Electrical Safety Authority (ESA) - official code information and technical bulletins
- ESA Notifications & Inspections - how to file permits and request inspections
Frequently Asked Questions
When does the 2024 OESC take effect?
The 29th Edition came into effect May 1, 2025. All new electrical permits must comply from that date.
What are the biggest changes?
Updated GFCI and outdoor-receptacle rules, new EV infrastructure provisions (Section 86), a rewrite of the energy storage rules, enhanced pool bonding, and maximum-load labelling.
Are AFCI breakers required in all rooms now?
AFCI protection has extended beyond bedrooms to most dwelling-unit receptacle circuits since the 2015 OESC, subject to the exceptions in Rule 26-658. See our AFCI requirements guide for specific room-by-room details.
