SSQ 1/5K Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The SSQ 1/5K is a 1 A, 125 V AC/DC surface mount board mount fuse manufactured by Bel Fuse Inc. in a 2-SMD, Square End Block package. This part is classified as Not For New Designs, indicating it has been superseded in the manufacturer's product line. Organizations using this fuse in active production or maintenance applications require equivalent substitute parts that maintain electrical and mechanical compatibility while offering active product status and improved availability.

Substiute Parts

SSQ 1/5K

Bel Fuse Inc.In Stock: 827SSQ 1/5K Datasheet

Current PartRFQ

0679L1000-05

Bel Fuse Inc.In Stock: 1239190679L1000-05 Datasheet

DirectRFQ

0476001.MR

Littelfuse Inc.In Stock: 14110476001.MR Datasheet

DirectRFQ

0476001.MRSN

Littelfuse Inc.In Stock: 43730476001.MRSN Datasheet

DirectRFQ

0451001.MRSN

Littelfuse Inc.In Stock: 18100451001.MRSN Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SSQ 1/5K are categorized based on electrical parameter compatibility and mechanical fit within the 2-SMD, Square End Block package envelope. The primary substitution criteria are:

Direct Electrical Equivalents (Identical Voltage Ratings): Parts maintaining 1 A current rating with 125 V AC and 125 V DC voltage ratings are classified as direct substitutes. These parts preserve the original circuit protection characteristics and require no design modification.

Voltage-Enhanced Substitutes (Higher AC Voltage Rating): Parts rated for 1 A at 250 V AC and 125 V DC provide increased AC voltage margin while maintaining DC voltage compatibility. These parts are suitable for circuits operating at or below 125 V AC/DC and offer enhanced protection capability in higher voltage environments.

Similar Mechanical Substitutes (Dimensional Variance): Parts sharing the 0.240" length dimension with minor width and height variations within the 2-SMD, Square End Block package classification are evaluated for PCB footprint compatibility. Dimensional differences of ±0.006" in width and height remain within typical SMD placement tolerances.

Parameter Comparison

Engineering Selection Recommendations

0679L1000-05 (Bel Fuse Inc.): This part provides direct electrical equivalence with identical voltage ratings (125 V AC/DC) and maintains the same 2-SMD, Square End Block package with matching 6.10 mm length and 2.54 mm width/height dimensions. Product status is Active with AEC-Q200 and cURus certifications. This substitute is recommended for applications requiring exact dimensional and electrical compatibility with the original SSQ 1/5K design.

0476001.MRSN (Littelfuse Inc., NANO²® 476 Series): This part offers 1 A current rating with enhanced 250 V AC voltage rating while maintaining 125 V DC compatibility. Product status is Active with cURus certification and REACH Unaffected status. The 2-SMD, Square End Block package has identical 6.10 mm length with 2.69 mm width and height dimensions, representing a 0.15 mm increase in both axes. This substitute is suitable for circuits operating at or below 125 V AC/DC where increased AC voltage margin is beneficial and PCB footprint tolerance accommodates the dimensional variance.

0476001.MR (Littelfuse Inc., NANO²® 476 Series): This part shares electrical and dimensional characteristics with 0476001.MRSN, offering 1 A at 250 V AC/125 V DC with Active product status and cURus certification. REACH Status is Affected. Selection between 0476001.MR and 0476001.MRSN depends on REACH compliance requirements for the end application.

0451001.MRSN (Littelfuse Inc., NANO²® 451 Series): This part provides direct electrical equivalence with 1 A at 125 V AC/DC and Active product status. The 2-SMD, Square End Block package has identical 6.10 mm length with 2.69 mm width and height dimensions. Certifications include CSA and UR. This substitute is recommended where dimensional tolerance of ±0.15 mm in width and height is acceptable and Littelfuse product line preference is specified.

Frequently Asked Questions (FAQ)

Q: Can the 0679L1000-05 be used as a direct replacement for the SSQ 1/5K without PCB modification?

A: Yes. The 0679L1000-05 maintains identical electrical ratings (1 A, 125 V AC/DC) and package dimensions (6.10 mm × 2.54 mm × 2.54 mm). No circuit design or PCB layout changes are required.

Q: What is the difference between 0476001.MR and 0476001.MRSN?

A: Both parts are electrically and dimensionally identical (1 A, 250 V AC/125 V DC, 6.10 mm × 2.69 mm × 2.69 mm). The primary difference is REACH compliance status: 0476001.MR is REACH Affected, while 0476001.MRSN is REACH Unaffected. Selection depends on regulatory requirements for the end application.

Q: Will the 0451001.MRSN fit the same PCB footprint as the SSQ 1/5K?

A: The 0451001.MRSN has identical length (6.10 mm) but increased width and height (2.69 mm vs. 2.54 mm). This 0.15 mm increase in both axes falls within standard SMD placement tolerances. Verify PCB footprint clearance, particularly in high-density layouts.

Q: Are the Littelfuse NANO²® 476 series parts (0476001.MR and 0476001.MRSN) suitable for 125 V AC circuits?

A: Yes. The 250 V AC rating provides margin above the 125 V AC circuit requirement. These parts are suitable for circuits operating at or below 125 V AC and 125 V DC.

Q: What certifications apply to each substitute part?

A: 0679L1000-05 carries AEC-Q200 and cURus certifications. 0476001.MR and 0476001.MRSN carry cURus certification. 0451001.MRSN carries CSA and UR certifications. Verify certification requirements for your specific application before selection.

Q: Is the SSQ 1/5K still available for new designs?

A: No. The SSQ 1/5K is classified as Not For New Designs. For new circuit designs, select from the Active status substitutes: 0679L1000-05, 0476001.MR, 0476001.MRSN, or 0451001.MRSN.