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CSA C22.2 No. 248.1-11 (2017): General Requirements for Low-Voltage Fuses
Comprehensive Overview of the Canadian Standard for Fuse Safety, Performance, and Compliance
Scope and Application
CSA C22.2 No. 248.1-11 (2017) is the current Canadian national standard that establishes the general requirements for low-voltage fuses rated up to 1000 V ac or 1500 V dc. It is the harmonized Canadian adoption of the UL 248‑1 standard and forms the foundation for all part‑specific fuse standards in the C22.2 No. 248 series, including those for Class H, J, L, R, T, and supplementary fuses. The standard applies to fuses intended to provide overcurrent protection in ordinary locations in accordance with the Canadian Electrical Code (CE Code) Part I.
This standard covers fuses of various classes – including non‑renewable (one‑time) and renewable types – as well as fuse holders, fuse links, and fuse disconnects. It defines the operating characteristics, construction requirements, performance tests, and marking provisions that ensure safe and reliable operation within the Canadian regulatory framework. Compliance with CSA C22.2 No. 248.1‑11 is a prerequisite for CSA certification of low-voltage fuses for the Canadian market.
Scope Tip: Even though this standard is harmonized with UL 248‑1, manufacturers must be aware of specific Canadian deviations, such as ambient temperature conditions (30 °C instead of 25 °C for some tests) and the requirement for English and French markings. Always refer to the latest CE Code amendments.
Technical Requirements and Testing
Construction and Materials
All fuse constructions must meet stringent material, dimensional, and creepage distances defined in the standard. For example, fuse bodies must be made of flame‑retardant, moisture‑resistant insulating material that withstands the dielectric voltage‑withstand test (1250 V or 1500 V for 600 V rated fuses). Blade contacts, ferrule caps, and terminals must be of copper, brass, or other corrosion‑resistant material with sufficient cross‑section to carry the rated current without exceeding the temperature rise limits specified in Table 1.
Electrical Performance and Testing
The standard prescribes a comprehensive set of type tests, including:
- Temperature rise test – conducted at 110 % rated current until thermal equilibrium; maximum temperature rise is typically 100 °C above ambient for contacts.
- Overload test – 200 % rated current for a defined number of cycles; the fuse must not open prematurely.
- Short‑circuit interruption test – verifies that the fuse can safely interrupt the available prospective short‑circuit current (up to 200 kA rms symmetrical) without sustaining external arcing or emitting flaming particles.
- Time‑current characteristic test – to verify the melting and clearing times at various multiples of rated current.
- Dielectric voltage‑withstand test – 60 Hz for 1 minute, to ensure adequate insulation between live parts and accessible surfaces.
| Fuse Class | Maximum Temperature Rise at 110 % Rated Current (Contacts/Terminals) | Maximum Temperature Rise (Fuse Body) | Ambient Temperature Basis |
|---|---|---|---|
| Class H, K, R | 100 °C | 80 °C | 30 °C |
| Class J | 90 °C | 75 °C | 30 °C |
| Class L | 100 °C | 80 °C | 30 °C |
| Class T | 100 °C | 80 °C | 30 °C |
| Supplementary fuses | 85 °C | 70 °C | 30 °C |
Testing Caution: The short‑circuit test requires careful calibration of the test circuit to ensure a realistic power factor and X/R ratio. Also, for fuses rated over 600 V, the standard demands a clear distance test to prevent flashover. These tests must be performed by an accredited laboratory (e.g., CSA Group, Intertek, UL).
Implementation Considerations for Manufacturers and Engineers
Designers integrating CSA‑certified fuses into electrical equipment must consider the following:
- Voltage ratings: The standard covers ac ratings up to 1000 V and dc ratings up to 1500 V, but each fuse class imposes specific voltage limitations (e.g., Class H only up to 250/600 V).
- Ambient temperature derating: The temperature rise tests are based on a 30 °C ambient. For higher ambient conditions (e.g., 40 °C or 50 °C), the fuse must be derated per manufacturer’s instructions or the current rating must be reduced accordingly.
- Short‑circuit current rating (SCCR): The interrupting rating of the fuse must equal or exceed the available fault current at the point of installation under worst‑case conditions.
- Harmonic currents: For applications where current waveforms include harmonics, the rms value of the fundamental plus harmonic components should not exceed the fuse’s ampere rating; the standard does not explicitly require harmonic testing but recommends referring to IEEE 242.
Success Checklist: When selecting a fuse for a new panelboard design, verify that (1) the fuse is CSA‑certified per 248.1‑11, (2) the SCCR is ≥ available fault current, (3) the fuse’s I²t curve coordinates with downstream components, and (4) the holder is listed for the same fuse class.
Compliance and Certification Pathway
Fuses placed on the Canadian market must be certified by a Standards Council of Canada (SCC)‑accredited certification body. The certification process typically involves:
- Submission of product samples and construction data to the certification body.
- Review of manufacturing quality control (QMS) per ISO 9001 or equivalent.
- Complete type testing per the clauses of CSA C22.2 No. 248.1‑11 and the applicable part‑specific standard (e.g., CSA C22.2 No. 248.8 for Class J fuses).
- Factory inspection and periodic follow‑up audits.
- Marking of each fuse with the CSA mark, rating, and catalogue number.
Critical Compliance Issue: Fuses that are UL‑listed for the U.S. but not CSA‑certified are not automatically accepted by Canadian authorities under the Canadian Electrical Code. Even if the product is virtually identical, the CSA standard includes unique requirements such as marking in both English and French, different ambient test conditions, and additional mechanical tests (e.g., insertion/withdrawal for blade fuses).
It is important to note that CSA C22.2 No. 248.1‑11 is a dynamic document; the 2017 edition is currently referenced, but a revision may be in progress. Manufacturers should monitor the CSA Group’s standards development for updates.
Frequently Asked Questions
Q: What is the difference between CSA C22.2 No. 248.1‑11 and UL 248‑1?
A: The technical content is nearly identical because it is a harmonized standard. However, CSA includes Canadian national differences: (a) ambient temperature for testing is 30 °C rather than 25 °C in UL, (b) marking must be bilingual (English and French), (c) the standard references the Canadian Electrical Code rather than the NEC, and (d) some fuse classes have unique dimensional requirements due to Canadian socket configurations. The structure and test philosophies are the same.
A: The technical content is nearly identical because it is a harmonized standard. However, CSA includes Canadian national differences: (a) ambient temperature for testing is 30 °C rather than 25 °C in UL, (b) marking must be bilingual (English and French), (c) the standard references the Canadian Electrical Code rather than the NEC, and (d) some fuse classes have unique dimensional requirements due to Canadian socket configurations. The structure and test philosophies are the same.
Q: Can I use a UL‑listed fuse in a Canadian installation without CSA certification?
A: In general, no. The Canadian Electrical Code requires that all electrical products be approved (certified) by a recognized certification body accredited by the SCC. A UL listing alone does not suffice unless the product also carries the appropriate CSA mark or an equivalent reciprocal recognition mark (e.g., UL’s C‑UL mark, which indicates certification to Canadian standards). Always verify that the fuse bears the CSA mark or a C‑UL (Canada) mark showing compliance to CSA C22.2 No. 248.1‑11.
A: In general, no. The Canadian Electrical Code requires that all electrical products be approved (certified) by a recognized certification body accredited by the SCC. A UL listing alone does not suffice unless the product also carries the appropriate CSA mark or an equivalent reciprocal recognition mark (e.g., UL’s C‑UL mark, which indicates certification to Canadian standards). Always verify that the fuse bears the CSA mark or a C‑UL (Canada) mark showing compliance to CSA C22.2 No. 248.1‑11.
Q: What is the validity of the 2017 edition? Has it been superseded?
A: As of 2026, the current edition is still CSA C22.2 No. 248.1‑11 (including amendments, e.g., Amendment 1 published in 2019). A new edition may be published in the future; however, the 2017 edition remains the referenced version in the Canadian Electrical Code (2024 edition). Always verify with the local authority having jurisdiction (AHJ) and the CE Code table of standards.
A: As of 2026, the current edition is still CSA C22.2 No. 248.1‑11 (including amendments, e.g., Amendment 1 published in 2019). A new edition may be published in the future; however, the 2017 edition remains the referenced version in the Canadian Electrical Code (2024 edition). Always verify with the local authority having jurisdiction (AHJ) and the CE Code table of standards.
Technical Article — Compliance with CSA C22.2 No. 248.1‑11 (2017) — Published 2026