2JS 125-R Equivalent & Substitute Parts

Part Overview

The 2JS 125-R is a 125 mA slow-blow glass cartridge fuse manufactured by Bel Fuse Inc., rated for 350 V AC and 140 V DC operation. This component is classified as obsolete, necessitating identification of functionally equivalent alternatives for ongoing system maintenance and new designs. The fuse requires a 2AG holder and operates across a temperature range of -55°C to 125°C with ROHS3 compliance and CSA/cURus approvals.

Substiute Parts

2JS 125-R

Bel Fuse Inc.In Stock: 11452JS 125-R Datasheet

Current PartRFQ

BK/C519-125-R

Eaton - Electronics DivisionIn Stock: 865BK/C519-125-R Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 2JS 125-R is determined by the following critical parameters:

• Current Rating: Must be 125 mA
• Fuse Type: Must be Cartridge, Glass
• Package / Case: Must be 2AG, 5mm x 15mm
• Response Time: Must be Slow Blow
• Voltage Rating - AC: Must meet or exceed 350 V AC
• Voltage Rating - DC: Must meet or exceed 140 V DC
• Mounting Type: Must require 2AG holder

The BK/C519-125-R from Eaton - Electronics Division meets the current rating, fuse type, package specification, response time, and mounting requirements. However, the AC voltage rating is 250 V, which is below the 350 V requirement of the main part. The DC voltage rating is not specified in the substitute part data. This substitute is suitable only for applications where the actual operating voltage does not exceed 250 V AC.

Parameter Comparison

Engineering Selection Recommendations

The BK/C519-125-R is electrically compatible with the 2JS 125-R only in applications where the system voltage does not exceed 250 V AC. The main part's 350 V AC rating provides higher voltage margin. Both components share ROHS3 compliance and CSA approval, supporting regulatory continuity. The BK/C519-125-R carries active product status, ensuring ongoing availability, whereas the 2JS 125-R is obsolete. Selection should be based on actual circuit voltage requirements and breaking capacity needs, as the BK/C519-125-R provides lower breaking capacity (35A versus 100A AC/150A DC).

Frequently Asked Questions (FAQ)

Q: Can the BK/C519-125-R directly replace the 2JS 125-R in all applications?

A: No. While both are 125 mA slow-blow glass cartridge fuses in 2AG packages, the BK/C519-125-R is rated for 250 V AC maximum, whereas the 2JS 125-R is rated for 350 V AC. Direct substitution is only valid for circuits operating at 250 V AC or below.

Q: What is the significance of the breaking capacity difference?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. The 2JS 125-R breaks up to 100A AC and 150A DC, while the BK/C519-125-R breaks up to 35A. In high-fault-current circuits, the lower breaking capacity may be insufficient.

Q: Are both fuses mechanically compatible with the same holder?

A: Yes. Both components use the 2AG package specification (5mm x 15mm) and require a 2AG holder. Physical installation is compatible.

Q: What compliance certifications apply to each part?

A: The 2JS 125-R holds CSA and cURus approvals. The BK/C519-125-R holds CSA and UL approvals. Both are ROHS3 compliant and REACH unaffected.

Q: Why is the 2JS 125-R listed as obsolete?

A: Obsolete status indicates the manufacturer has discontinued production. The BK/C519-125-R, with active status, represents a current alternative for new designs and ongoing inventory replenishment.