SSQ 800/5K Equivalent & Substitute Parts

Part Overview

The SSQ 800/5K is an 800 mA surface mount board mount fuse rated for 125 V AC/DC operation, manufactured by Bel Fuse Inc. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and procurement planning. The fast blow response time and 2-SMD square end block package are critical design parameters for applications requiring this specific fuse characteristic and form factor.

Substiute Parts

SSQ 800/5K

Bel Fuse Inc.In Stock: 973SSQ 800/5K Datasheet

Current PartRFQ

0451.800MRSN

Littelfuse Inc.In Stock: 8110451.800MRSN Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SSQ 800/5K is determined by strict equivalence across the following parameters:

• Current Rating: 800 mA (exact match required)
• Voltage Rating: 125 V AC minimum; DC rating must support 125 V or higher
• Response Time: Fast Blow characteristic
• Mounting Type: Surface Mount
• Package / Case: 2-SMD, Square End Block form factor
• Operating Temperature Range: -55°C to 125°C minimum
• RoHS Compliance: ROHS3 Compliant
• Moisture Sensitivity Level: 1 (Unlimited)

The substitute part 0451.800MRSN (Littelfuse Inc., NANO²® 451 series) meets all critical substitution criteria. Physical dimensions show minor variation (0.106" W x 0.106" H versus 0.100" W x 0.100" H), which remains within acceptable tolerance for 2-SMD square end block packages in standard PCB footprints.

Parameter Comparison

Engineering Selection Recommendations

The 0451.800MRSN from Littelfuse Inc. is the qualified substitute for the obsolete SSQ 800/5K. Selection is based on:

• Identical current rating, voltage rating, and response time characteristics
• Matching 2-SMD square end block package form factor with acceptable dimensional tolerance
• Active product status ensuring ongoing availability and supply chain continuity
• ROHS3 compliance and unlimited moisture sensitivity rating alignment
• CSA and UR approvals providing regulatory coverage for most industrial applications

The SSQ 800/5K carries CE, CSA, and cULus certifications. The substitute part carries CSA and UR certifications. Applications requiring CE or cULus certification should confirm regulatory acceptance of the substitute part with the system integrator or regulatory authority.

Frequently Asked Questions (FAQ)

Q: Can the 0451.800MRSN be used as a direct replacement for the SSQ 800/5K?

A: Yes, the 0451.800MRSN meets all critical electrical and mechanical parameters for substitution. Both parts share identical current rating (800 mA), voltage rating (125 V AC), response time (Fast Blow), mounting type (Surface Mount), and package form factor (2-SMD, Square End Block). Physical dimensions differ by 0.006" in width and height, which is within acceptable tolerance for standard PCB footprints.

Q: What are the key parameters that determine if a fuse can substitute for the SSQ 800/5K?

A: Substitution requires exact match on: current rating (800 mA), voltage rating (125 V AC minimum), response time (Fast Blow), mounting type (Surface Mount), and package form factor (2-SMD, Square End Block). Operating temperature range must support -55°C to 125°C. RoHS compliance and moisture sensitivity level must align with ROHS3 and MSL 1 (Unlimited).

Q: Are there dimensional differences between the SSQ 800/5K and 0451.800MRSN?

A: Yes. The SSQ 800/5K measures 0.240" L x 0.100" W x 0.100" H (6.10mm x 2.54mm x 2.54mm). The 0451.800MRSN measures 0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm). The length is identical; width and height differ by 0.006" (0.15mm). This variation is within standard PCB footprint tolerance for 2-SMD square end block packages.

Q: What certifications does the substitute part carry?

A: The 0451.800MRSN carries CSA and UR approvals. The original SSQ 800/5K carries CE, CSA, and cULus certifications. Applications requiring CE or cULus certification should confirm regulatory acceptance with the system integrator or applicable regulatory body.

Q: Is the 0451.800MRSN currently available?

A: Yes, the 0451.800MRSN is classified as Active product status with 755 pieces in new original stock, ensuring supply chain availability for procurement and replacement applications.