Canadian Electrical Code vs Ontario Electrical Safety Code: How They Fit Together

People often talk about "the code" as if there were a single rulebook for wiring a house in Canada. There are really two layers. The Canadian Electrical Code is a national standard written and published by CSA Group, and on its own it is voluntary. Each province and territory then decides how to give it legal force. Ontario does that through a provincial regulation that adopts the national text along with a set of Ontario changes, and the result is the Ontario Electrical Safety Code, usually shortened to the OESC.

This post explains what the national code contains, the difference between its Part I and Part II, how often a new edition is published, how Ontario adopts it, which edition applies here today, and what all of that means when you are planning a renovation, a panel change or any other electrical project at home.

What Is the Canadian Electrical Code?

The Canadian Electrical Code, Part I is published by CSA Group as standard CSA C22.1, and its full title calls it a safety standard for electrical installations. CSA notes that it was developed as a voluntary code, yet every province and territory references CSA C22.1 as the basis for its own electrical safety acts and regulations and enforces compliance through its own laws.

That split explains a lot of confusion. CSA writes the technical rules, but it does not inspect houses or issue permits. Enforcement belongs to each province. CSA also says that every jurisdiction decides for itself which edition of C22.1 its regulations point to, so the edition being enforced in one province is not automatically the newest one on the shelf, and it can differ from what a neighbouring province uses.

Canadian Electrical Code Part 1 and Part 2: What Each Covers

The national code has two parts that do different jobs.

Part I (CSA C22.1) is the installation code. It sets the safety requirements for electrical installations, and CSA says each new edition aims to make installation and maintenance work safer. This is the part an electrician plans a job around and an inspector checks against.

Part II is a family of product safety standards numbered in the CSA C22.2 series. CSA describes them as covering the design and construction of electrical equipment, mainly to deal with fire and shock hazards. A general requirements standard, C22.2 No. 0, applies across all of the individual Part II standards, and each individual standard then covers one class of product, such as a type of cable, a power supply or a control device.

The two parts meet in your home. CSA notes that the Part II series holds the large majority of the standards used to certify electrical equipment for approved use in Canada, while Part I governs how that equipment is installed. When you shop for fixtures or devices, look for a recognized certification mark on the product.

How Often New Editions Come Out: The Canadian Electrical Code 2024

CSA states that the Code is updated every three years. The current national edition is CSA C22.1:24, which CSA identifies as the 26th edition of Part I. Earlier editions came out in 2021, 2018 and 2015, which shows the same three-year rhythm.

CSA also publishes a companion handbook, CSA C22.1HB:24, that explains the reasoning behind many rules. CSA is careful to say the handbook does not cover every clause; it only addresses sections and clauses that need further clarification. It is a study aid, and the code itself remains the document that sets the requirements.

A new national edition does not change the rules in Ontario on the day it is published. The province has to amend its regulation first, and the new requirements apply from the date the province sets.

How Ontario Turns the National Code Into the OESC

Ontario's legal hook is Ontario Regulation 164/99, the Electrical Safety Code regulation made under the Electricity Act, 1998. The regulation requires that every act or omission connected with the generation, transmission, distribution, retail or use of electricity in Ontario comply with the Electrical Safety Code.

The regulation adopts the CSA standard Canadian Electrical Code Part 1, C22.1:24, as amended by a separate document titled Ontario Amendments to the Canadian Electrical Code Part 1, C22.1, dated June 12, 2024. The regulation also directs the Electrical Safety Authority (ESA) to make sure copies of the code are available to the public.

Put simply, the OESC code is the national Part I text with Ontario's amendments layered on top. ESA describes the 2024 edition the same way: the Canadian Electrical Code, Part I, plus several Ontario-specific amendments. Because of those amendments, a rule in the Canadian book may read differently in Ontario, so anyone working here should read from the Ontario edition rather than the plain national text.

Which Edition Applies in Ontario Right Now

The 2024 Ontario Electrical Safety Code, which ESA numbers as the 29th edition, took effect on May 1, 2025. Note the two numbering systems: CSA counts the national Part I as its 26th edition, while ESA counts the Ontario publication as its 29th. Both refer to the same 2024 cycle.

ESA set out a transition for the changeover. Work under a notification or plan review submission made before May 1, 2025 did not have to comply with the 2024 OESC and could follow the rules in force when it was filed. ESA's summary of the new edition points to changes that matter in houses, including more outdoor receptacle requirements for single dwellings, labelling of the maximum residential load, a rewrite of the rules for energy storage systems at residential occupancies and enhanced bonding continuity requirements for pools and hot tubs.

If you are comparing a quote or a plan with something you read online, check which edition the source is describing. Advice written for the 2021 rules, or for another province, may not match what an Ontario inspector applies to a notification filed today.

The OESC Simplified: What It Means for a Homeowner

You do not need to read the code to stay on the right side of it, but a few points from ESA are worth knowing.

File first. ESA says a notification of work must be filed before electrical work starts. The person who does the work files it, so a Licensed Electrical Contractor you hire files it for you. A building permit from your municipality is a different thing and does not replace the electrical notification; some projects need both.

Expect inspection. ESA reviews the work against the OESC, and work that will be hidden in walls or buried generally has to be seen before it is covered.

Keep the certificate. Once the work is reviewed and passes, ESA issues an ESA Certificate of Acceptance to the person who filed the notification, and ESA says the certificate shows the work meets the OESC. When a contractor filed it, ask for a copy for your records. ESA also takes requests for copies at 1-877-ESA-SAFE (372-7233).

For the common problems inspectors flag in houses, see our post Common Electrical Code Violations in Ontario Homes, which goes through ESA's warnings in detail.

Where to Buy or View a Canadian Electrical Code Book

The code is a copyrighted CSA standard, so it is sold rather than posted freely, and copies offered as free downloads on unofficial sites should be avoided. There are two legitimate routes.

The Ontario edition. ESA directs buyers of the OESC to CSA Group, online at csagroup.org/oesc or by phone at 800-463-6727. ESA describes both a printed book and a searchable digital version that works on phones, tablets and desktop computers.

The national edition. CSA sells CSA C22.1:24 through its online store, delivered as a PDF through its CSA OnDemand service. CSA's product page also offers view access to the document for people in Canada, which requires a free user account. Viewing the national text is useful for background, but remember that it does not include Ontario's amendments.

For a homeowner with a specific question about a project, ESA's homeowner pages and a licensed contractor are a more practical starting point than the full standard.

Who Can Do Code Work in Your Home

ESA's rule on who may do electrical work is short. You can do electrical work in your own home if you file the notification yourself. Friends, family members and neighbours are not allowed to do it for you. If you pay someone, the law requires a Licensed Electrical Contractor, and ESA states that general contractors and handypersons are not permitted to be hired for the electrical portion. Our post Why You Should Only Hire an ESA-Licensed Electrician in Ontario explains how to check a contractor's licence before you sign.

KV Bear Electrical is a Licensed Electrical Contractor (ECRA/ESA 7014730) and files the ESA notification for the work it does under the edition of the code in force at the time. To plan a renovation, a panel change or an inspection of existing wiring, call 905-999-5048 or request a quote.