MS 1.5 Equivalent & Substitute Parts Reference

Part Overview

The MS 1.5 is a board mount axial fuse manufactured by Bel Fuse Inc., rated for 1.5 A at 125 V AC/DC with slow blow response characteristics. This component is classified as obsolete, making equivalent substitutes necessary for ongoing design support and procurement. The MS 1.5 series fuse is designed for through-hole mounting applications requiring reliable overcurrent protection in low-voltage circuits.

Substiute Parts

MS 1.5

Bel Fuse Inc.In Stock: 739MS 1.5 Datasheet

Current PartRFQ

047301.5MRT1L

Littelfuse Inc.In Stock: 2165047301.5MRT1L Datasheet

DirectRFQ

047301.5YRT1L

Littelfuse Inc.In Stock: 16265047301.5YRT1L Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the MS 1.5 is based on strict electrical and mechanical parameter matching:

Primary Substitution Criteria:

• Current Rating: 1.5 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)
• Package / Case: Axial (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

The substitute parts identified—047301.5MRT1L and 047301.5YRT1L—are both manufactured by Littelfuse Inc. under the PICO® II 473 series. These parts meet all critical electrical parameters and mounting requirements. The primary difference between substitutes is packaging format: Cut Tape (CT) versus Tape & Reel (TR), which affects procurement and assembly processes but not electrical performance.

Parameter Comparison

Engineering Selection Recommendations

Both Littelfuse PICO® II 473 series fuses (047301.5MRT1L and 047301.5YRT1L) are active products with current manufacturing support, providing long-term availability compared to the obsolete MS 1.5. Both substitutes carry CSA and UR certifications, meeting regulatory requirements for board mount fuse applications.

047301.5MRT1L (Cut Tape): Suitable for lower-volume production runs, prototype builds, and applications where individual component handling is required.

047301.5YRT1L (Tape & Reel): Recommended for high-volume manufacturing and automated assembly processes due to standard reel packaging format and higher inventory availability (16,200 pcs in stock versus 2,100 pcs for the CT variant).

Both substitutes achieve ROHS3 compliance, supporting modern environmental and regulatory standards. The dimensional variance (0.135" diameter versus 0.125" for the original) requires PCB layout verification to confirm clearance in existing board designs.

Frequently Asked Questions (FAQ)

Q: Can 047301.5MRT1L and 047301.5YRT1L be used interchangeably?

A: Yes. Both parts are electrically and mechanically identical. The only difference is packaging format: Cut Tape versus Tape & Reel. Selection depends on procurement volume and assembly process requirements.

Q: What is the impact of the dimensional difference (0.125" vs 0.135" diameter)?

A: The substitute parts have a slightly larger diameter (0.135" versus 0.125"). PCB hole sizing and component placement must be verified to ensure adequate clearance. The axial length remains functionally equivalent at 0.280".

Q: Are the substitute parts compatible with existing board designs using MS 1.5?

A: Electrical compatibility is confirmed. Mechanical compatibility requires verification of PCB hole diameter and component spacing to accommodate the larger 0.135" diameter of the substitute fuses.

Q: Why is the DC Cold Resistance different (0.116 Ohms vs 0.172 Ohms)?

A: The resistance difference reflects different internal element designs between manufacturers. Both values are within acceptable ranges for 1.5 A fuses and do not affect functional performance in standard circuit protection applications.

Q: Which substitute should be selected for new designs?

A: For new designs, either substitute is acceptable. Use 047301.5YRT1L (Tape & Reel) for production volumes exceeding 500 units. Use 047301.5MRT1L (Cut Tape) for prototypes, low-volume builds, or applications with specific packaging constraints.

Q: Are there any compliance differences between the original and substitutes?

A: The original MS 1.5 carries CE, CSA, and cURus certifications. The substitutes carry CSA, PSE, and UR certifications. Both meet industry standards for board mount fuses. The substitutes additionally provide ROHS3 compliance, supporting modern environmental regulations.