Ontario Electrical Safety Code (OESC), 29th Edition - 2024

Paper format is available for pre-order. Order now and have your order shipped when it becomes available late January 2025.

Overview

The 29th edition of the Ontario Electrical Safety Code (OESC) includes the 26th edition of the Canadian Electrical Code, Part I, plus Ontario-specific amendments. The OESC is the law in Ontario for electrical installation. This new edition has been updated to enhance electrical safety and better protect electrical workers and the public.

Highlights and key changes:

The new edition of the OESC introduces several significant updates to wiring and installation requirements, including:

1. Enhancing Plan Review requirements to include submission for some electric vehicle supply equipment (EVSE) installations, and to include stand-alone electric-power-generating-equipment and systems 

2. Revising demand load calculation for single dwellings with EVSE loads

3. Enabling electrification by recognizing other types of energy management systems in addition to electric vehicle energy management system

4. Complete rewrite of the installation requirements of energy storage systems (ESS )at residential occupancies

5. Preventing electrical shock hazards with additional requirements for outdoor receptacles for single dwellings

6. Preventing overloading in the future by requiring labelling of maximum residential load 

7. Permitting insulated conductors within an enclosure when connected to different sources of voltage, with specific conditions

8. Protecting the public with additional GFCI requirements for cords used at midways, carnivals, fairs, and festivals

9. Increase in allowable voltages in electric vehicle supply equipment installations

Why you need the new edition of the Ontario Electrical Safety Code

Compliance with the requirements of the latest edition of the OESC is the law for anyone performing electrical installations in the province of Ontario. The new OESC is based on the 26th edition of the Canadian Electrical Code, Part I, which is developed through the efforts of a number of volunteer technical committees and subcommittees representing key electrical industry stakeholders and jurisdictions across Canada.

Updated every three years in collaboration with safety partners, the 2024 OESC reflects changes in technologies and best practices, and helps decrease the risk of injuries and costly re-works of electrical installation projects in Ontario.

Preface to the 29th edition of the Ontario Electrical Safety Code

This edition of the Ontario Electrical Safety Code contains the standards referenced by the Ontario Regulation made in 2024 pursuant to the Electricity Act regarding the Ontario Electrical Safety Code. Reference should always be made to the Regulation, and amendments thereto, as may be made from time to time.

This edition contains electrical safety requirements for wiring and equipment in buildings, structures, and premises, with the exception of mines, railways, aircraft, marine vessels, installations used for communication purposes, and automobiles.

As electrical hazards occur mainly because of overloading and abuse of wiring systems, it is recommended that initial installations be planned with adequate provision for possible future uses of electricity.

The 29th edition of the Ontario Electrical Safety Code consists of CSA C22.1:24, Canadian Electrical Code, Part I, and the Ontario Amendments to CSA C22.1:24, Canadian Electrical Code, Part I, dated November 2024.