ULC vs UL: What Actually Counts in Canada

Start here: a standard is not a mark

This one distinction resolves most of the confusion, so get it straight before anything else.

Those are two separate SCC accreditation programs, with separate criteria and separate files.

On SDO accreditation, SCC says:

This SCC accreditation signals that an organization is qualified to develop, publish and maintain National Standards of Canada, National Adoptions of Canada and Consensus Standards Development Organization Standards.

On certification body accreditation, SCC says:

This SCC accreditation signals that an organization is qualified to certify products, processes and services for which it is accredited, ensuring that standards are applied correctly and consistently.

That program is "based on ISO/IEC 17065, the international standard for providing product, process and services certification," and SCC describes its own role as creating "a foundation of trust by 'checking the checkers' and making sure certification bodies meet the requirements of national and international standards."

So when you look at a mark, you are looking at the output of the second program. When you look at a spec calling out CAN/ULC-S537, you are looking at the output of the first.

What "CAN" in CAN/ULC actually means

Nobody explains this, and it is the most useful thing in the designation.

"CAN" is not part of ULC's name or brand. It is a descriptor that SCC requires an accredited SDO to place in front of the designation.

From SCC's Requirements & Guidance for Standards Development Organizations (v6, 2025-03-06), a National Standard of Canada is:

A standard developed by an SCC-accredited SDO that is compliant to SCC's Requirements & Guidance for SDOs.

And clause 7.4:

The SDO shall use the 'CAN' descriptor preceding the standard designation, based on the identified strategic need in clause 4.2.1.

Read the designation left to right and it tells you three things:

• CAN — National Standard of Canada status, an SCC-mandated descriptor
• ULC — the developer's designation
• S524 — the document number in that series

So "CAN/ULC-S524" is not a brand name that happens to start with CAN. The CAN is doing specific work, and it is the part that says Canadian standard.

1 April 2025: ULC Standards is no longer a separate SDO

Most existing writing on this topic is now out of date. Here is what changed.

SCC, on the transfer:

Effective April 1st, 2025, ULC Standards transferred all their accreditation activities over to UL Standards & Engagement and Standards Council of Canada (SCC) merged ULC Standard's and UL Standards & Engagement Standards Development Organization Accreditation files.

All activities from both files are being continued as part the UL Standards & Engagement Accreditation file.

The surviving SDO file in SCC's directory:

ULSE's own SCC-Accredited Procedures (issued 2018-03-01, revised 2025-03-04) say the same thing in their own words, at §5.2.1:

Historically, both ULSE Inc. and ULC Standards (of which ULSE Inc. is a sole corporate member) performed standards development activities with respect to Canada...However, effective as of 2025, all UL/ULC Standards development activity will be performed by ULSE Inc.

And at §5.3.4:

...in 2024 (effective 2025), it was decided to merge the accreditations of ULC Standards and ULSE under a single accreditation for ULSE.

UL Solutions' Canadian page puts it this way:

In 2025 ULSE Inc consolidated its two separate accredited SDO's (ULC Standards and Underwriters Laboratories Inc.) into one SCC accredited SDO under ULSE Inc.

ULSE Inc publishes and maintains close to 300 Canadian safety standards and other related documents.

What this means on the ground: the sentence "ULC Standards is the SDO behind CAN/ULC" is no longer accurate. Since 1 April 2025 the accredited SDO is ULSE Inc. The CAN/ULC designations themselves continue — nothing in your spec became invalid on 1 April 2025.

Certification is a separate entity with a separate file

This is the part that trips people up: the standards merger did not merge the certification bodies. They are different organisations, in different SCC programs, with different file numbers and different addresses.

Note that both certification bodies — the Canadian one and the US one — hold SCC certification accreditation. That matters, and we come back to it under Ontario law below.

UL Solutions describes the Canadian certification body this way:

Underwriters Laboratories of Canada Inc., henceforth referred to as ULC on this page under the UL Solutions corporate brand in Canada is a product certification body that fulfills the requirements of ISO/IEC 17065. The ULC Safety Scheme (also referred to as Product Certification) is accredited by the Standards Council of Canada (SCC).

In Canada, ULC operates under its own authority as an independent, nongovernmental organization.

What the marks mean

The traditional ULC Listing Mark has four required elements, per UL Solutions' Canadian page:

• ULC in a circle symbol
• The word LISTED
• Product name or company name/file number
• Issue/serial number or alphanumeric control number

If those elements are not all there, you are not looking at a complete traditional ULC Listing Mark. And on the directory point, the same page is blunt:

A directory of certified products is available online via Product iQ (PiQ), however, only products bearing the mark are certified.

A listing in a database is not the same as a mark on the device in your hand.

The mark table

⚠️ Source note. The rows below describing the "C", "US" and "CA" indicators come from UL Solutions' own corporate description of its own mark scheme, published on its US-headquartered site (ul.com). This is UL explaining what UL's marks are intended to signify. It is not a Canadian legal authority and does not decide what your AHJ accepts. The Canadian legal position is in the next section.

UL also states, in the same self-description:

A UL Mark will be accepted in Canada if it has specific Canadian indicators, like 'CA' on the enhanced Mark, 'C' on the legacy Mark or the ULC Mark.

the cUL, ULC or UL enhanced Marks only featuring the 'CA' country code would not be accepted within the United States, as it implies testing and certification to Canadian standards only.

Take that for what it is: the certifier describing its own scheme. It is useful for decoding a mark. It is not the rule that binds your inspector.

What Canadian law actually requires

Now the authority section.

The definition of "listed" is an accreditation test

The definition below is from the revoked O. Reg. 332/12, Division A, Article 1.4.1.2 — quoted here because it states the test plainly:

Listed means equipment or materials included in a list published by a certification organization accredited by the Standards Council of Canada.

Read what that hinges on. Not the logo. Not general industry recognition. Not "everybody uses it." SCC accreditation of the certifying organisation. That is the test.

The Electrical Safety Authority says the same thing

ESA Bulletin 2-7-38:

The Ontario Electrical Safety Code (OESC) and Ontario Regulation 438/07, for Product Safety, recognize Certification Bodies accredited by the Standards Council of Canada to approve electrical equipment (Rule 2-024).

To meet the requirements of the OESC (Rules 2-022 and 2-024), equipment shall be approved to a recognized Canadian standard.

Two separate conditions in those two sentences, and you need both:

1. The body is SCC-accredited.
2. The standard it approved against is a recognized Canadian standard.

A US-listed product can satisfy the first and still not satisfy the second.

On enforcement, ESA's Recognized Approval Marks page:

Before an electrical product or piece of electrical equipment is used, sold, displayed or advertised for sale in Ontario, it must be approved by an accredited certification or evaluation agency. The item must carry the official mark or label of the agency which indicates that the product has been independently assessed for safety.

Installation and connection of unapproved electrical equipment is against the law, puts people at risk and can lead to prosecution.

The ESA nuance that actually matters on site

Read this one carefully, because it is easy to get wrong in both directions.

ESA's recognized list includes both "Underwriters' Laboratories of Canada (ULC)" and "Underwriters' Laboratories Inc." So it is simply not true that a UL mark is never accepted in Ontario.

But ESA also maintains a separate heading: "Component Certification Markings that are not Recognized on Complete End-use Products." Under that heading it lists "Underwriters Laboratories Inc. (UL)", with this note:

Electrical components bearing these marks may have restrictions on their performance or may be incomplete in construction, and are intended to be used as part of a larger approved product or system.

So the distinction ESA is drawing is component mark versus complete end-use product, not American versus Canadian:

The practical version: a component mark on a subassembly inside an approved panel is doing its intended job. The same component mark presented as the approval for the finished device you are about to energise is not.

Do not stretch this into "UL is never accepted." It does not say that.

The standards Ontario names, by designation and edition

Canadian codes do not say "use a suitable standard." They name specific documents and specific edition years.

Ontario Fire Code, O. Reg. 213/07, Division B, Rule 1.2.1.1.(1):

A reference in this Code to a document set out in Table 1.2.1.A. is to the edition designated in the table.

Table 1.2.1.A names:

The Fire Code figures are from the consolidation period beginning 1 January 2026 (e-Laws currency date 12 August 2026). The Building Code figures are from O. Reg. 163/24, in force 1 January 2025, which adopts NBC 2020 as amended; the free text is the 2024 Building Code Compendium Vol. 1, January 16, 2025 Update.

No US UL standard appears in those rows. Every fire alarm document named in either table is a CAN/ULC document.

Which edition binds you, and why the code year and the standard year are different numbers, is worked through in which ULC edition applies. What each of the standards actually covers is in S524, S537, S536 and S1001 explained.

The designations are in flux — the "S" is being dropped

If you are matching a spec against a published standard, expect the designation itself to have changed.

Both forms are in circulation. "CAN/ULC-524" and "CAN/ULC-S524" refer to the same series. A spec citing one and a published document titled the other is not necessarily a mismatch — check the edition year, which is the part that binds.

Note also the gap between the two tables above: the codes name 2019 editions while newer editions are published. Publication is not adoption.

The honest limit on all of this

We looked for a Canadian authority stating, in so many words, that an American UL standard is not automatically acceptable in Canada. We did not find one. No SCC page, no ESA document, no code provision we reviewed says that sentence.

What exists is indirect, and it is consistent:

• Canadian codes name CAN/ULC documents by designation and edition year, and no US UL standard appears in those fire alarm rows.
• The OESC, via ESA, requires equipment to be "approved to a recognized Canadian standard."
• "Listed" is defined by SCC accreditation of the certifying body, not by reputation.

That is a strong indirect case. It is not a direct quote, and we are not going to dress it up as one. If the acceptability of a specific product is live on your job, that is an AHJ question with a documented answer, not a thing to settle from a web page.

What to actually do with a device in your hand

1. Look for the Canadian indicator on the mark. The ULC-in-a-circle Listing Mark, or a Canadian indicator on a UL Mark. UL's own guidance on decoding those indicators is in the mark table above — labelled as UL's own.
2. Check the mark is complete. For the traditional ULC Listing Mark that is four elements: ULC in a circle, LISTED, product or company name and file number, and issue/serial or alphanumeric control number.
3. Confirm the certifying body is SCC-accredited for the relevant scope. SCC's directory is public and free.
4. Check the standard, not just the body. Which CAN/ULC document, which edition year, and does it match the edition your code table names.
5. Do not accept a component marking as the approval for a complete end-use product. That is ESA's own separate heading.
6. If it is still unclear, ask the AHJ before you energise it. ESA states that installing unapproved electrical equipment is against the law.

Circuit-side requirements — conductors, separation, mechanical protection — are a different chapter again: see CEC Section 32 and fire alarm circuits.

How to check any of this yourself, free

1. SCC's accreditation directories — search "Underwriters Laboratories of Canada, Inc" (file 10002), "UL LLC" (file 10011), and "UL Standards & Engagement" (file 30707). Free, public, and it shows you status, program and expiry.
2. ESA's Recognized Certification Marks page — free, and it has both the recognized list and the separate component-marking heading.
3. Ontario e-Laws, O. Reg. 213/07 — free. Division B, Table 1.2.1.A is where the fire alarm standards and their editions are named.
4. 2024 Building Code Compendium Vol. 1 — $0.00 from Publications Ontario. Table 1.3.1.2 is the Building Code's referenced-documents table.
5. The standards themselves are paywalled. SCC pages, ESA pages and the code tables are free; CAN/ULC-S524 and the rest are not. We do not reproduce paywalled standard text here.

Last updated: August 2026.

General information, not compliance advice. Product acceptability is an AHJ determination. Confirm against the code text in force for your project and with your authority having jurisdiction.