MS 5 Fuse Board Mount Equivalent & Substitute Parts

Part Overview

The MS 5 is a 5A 125VAC/125VDC board mount axial fuse manufactured by Bel Fuse Inc. This component is classified as Obsolete, making substitute parts necessary for ongoing system maintenance and new design implementations. The MS 5 serves as a protective device in electronic circuits requiring slow-blow response characteristics and through-hole mounting configuration.

Substiute Parts

MS 5

Bel Fuse Inc.In Stock: 1178MS 5 Datasheet

Current PartRFQ

0473005.MRT1L

Littelfuse Inc.In Stock: 52100473005.MRT1L Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MS 5 is determined by strict alignment with the following electrical and mechanical parameters:

• Current Rating: 5 A (exact match required)
• Voltage Rating: 125 V AC and 125 V DC (exact match required)
• Response Time: Slow Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Fuse Type: Board Mount, Axial configuration (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match or wider range acceptable)

The substitute part 0473005.MRT1L from Littelfuse Inc. meets all mandatory electrical and mechanical criteria for direct substitution. Minor dimensional variations within manufacturing tolerances and differences in melting I²t values do not preclude substitution when all primary parameters align.

Parameter Comparison

Engineering Selection Recommendations

The 0473005.MRT1L from Littelfuse Inc. is the qualified substitute for the obsolete MS 5. Selection is based on:

• Complete electrical parameter alignment (current, voltage AC/DC, response time)
• Identical mounting and package configuration (through-hole axial)
• Matching operating temperature range (-55°C ~ 125°C)
• Active product status ensuring supply chain availability
• Regulatory compliance through CSA, PSE, and UR certifications
• RoHS3 compliance status of the substitute part

The substitute part maintains functional equivalence for circuit protection applications. Dimensional differences (0.135" vs 0.125" diameter) fall within acceptable manufacturing tolerances for board mount through-hole applications.

Frequently Asked Questions (FAQ)

Q: Can the 0473005.MRT1L directly replace the MS 5 in existing designs?

A: Yes. Both parts share identical electrical ratings (5A, 125VAC/VDC, slow-blow response), mounting type (through-hole), and package configuration (axial). The substitute is functionally equivalent for circuit protection.

Q: What is the significance of the different melting I²t values (33 vs 54.8)?

A: Melting I²t describes the thermal energy required to melt the fuse element. The higher value in the substitute part indicates slightly different thermal characteristics but does not affect substitution eligibility when all primary electrical parameters match.

Q: Are there packaging differences between these parts?

A: The MS 5 is listed with packaging designation "-" while the 0473005.MRT1L is supplied in Cut Tape (CT) format. Both are through-hole axial fuses with compatible board mount configurations.

Q: What certifications apply to the substitute part?

A: The 0473005.MRT1L holds CSA, PSE, and UR approvals. The original MS 5 held CE, CSA, and cURus certifications. Verify that the substitute's certification profile meets your application requirements.

Q: Is the slight diameter difference (0.125" vs 0.135") a concern?

A: No. Both dimensions fall within standard manufacturing tolerances for axial fuses and are compatible with standard through-hole board mount footprints designed for 5A axial fuses.