Equivalent & Substitute Parts for BK/C520-125MA

Part Overview

The BK/C520-125MA is a 125 mA, 250 V AC/DC fast-blow glass cartridge fuse in 2AG form factor (5mm x 15mm) manufactured by Eaton - Electronics Division. This fuse is designed for circuits requiring fast response protection and operates within the C520 series specifications. The part is currently listed as obsolete, necessitating identification of active equivalent alternatives to maintain circuit protection functionality and ensure continued availability for replacement and new designs.

Substiute Parts

BK/C520-125MA

Eaton - Electronics DivisionIn Stock: 868BK/C520-125MA Datasheet

Current PartRFQ

BK/C520-125-R

Eaton - Electronics DivisionIn Stock: 1429BK/C520-125-R Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BK/C520-125MA is determined by strict equivalence across all electrical and mechanical parameters. The substitute part BK/C520-125-R maintains identical specifications in the following critical areas:

• Current Rating: 125 mA (exact match)
• Voltage Rating: 250 V AC (exact match)
• Fuse Type & Package: Cartridge, Glass in 2AG form factor, 5mm x 15mm (exact match)
• Response Characteristic: Fast Blow (exact match)
• Breaking Capacity: 35 A @ rated voltage (exact match)
• Thermal Characteristics: Melting I²t of 0.0019 (exact match)
• Electrical Properties: DC Cold Resistance of 15.2 Ohms (exact match)
• Certifications: CSA and UL approval (exact match)

The BK/C520-125-R is classified as an active product with improved RoHS3 compliance status, making it the direct functional and electrical equivalent for circuit protection applications requiring the BK/C520-125MA specifications.

Parameter Comparison

Engineering Selection Recommendations

The BK/C520-125-R is the direct equivalent substitute for the obsolete BK/C520-125MA. Selection of the BK/C520-125-R is based on the following engineering criteria:

Product Status: The BK/C520-125MA is obsolete, while BK/C520-125-R is active and currently in production. Active status ensures continued availability and supply chain reliability.

Electrical & Mechanical Equivalence: All critical parameters—current rating, voltage rating, response time, breaking capacity, thermal characteristics, and physical dimensions—are identical between the two parts. This ensures direct functional replacement without circuit redesign.

Regulatory Compliance: Both parts carry CSA and UL certifications. The BK/C520-125-R additionally meets RoHS3 compliance and REACH unaffected status, providing enhanced environmental and regulatory alignment for modern applications.

Packaging & Mounting: Both parts use identical 2AG cartridge form factor and require the same holder configuration, ensuring mechanical compatibility in existing circuit protection assemblies.

Frequently Asked Questions (FAQ)

Q: Can BK/C520-125-R be used as a direct replacement for BK/C520-125MA in existing circuits?

A: Yes. The BK/C520-125-R is electrically and mechanically identical to the BK/C520-125MA across all specified parameters. It operates at the same current rating (125 mA), voltage rating (250 V AC), response time (fast blow), and breaking capacity (35 A). Both parts use the same 2AG cartridge package and require identical holder configurations.

Q: What is the difference between the two parts?

A: The primary differences are product status and regulatory compliance. The BK/C520-125MA is obsolete, while BK/C520-125-R is an active product. The BK/C520-125-R meets RoHS3 compliance and REACH unaffected status, whereas the BK/C520-125MA is RoHS non-compliant. All electrical and mechanical specifications remain identical.

Q: Are there any compatibility concerns when substituting BK/C520-125-R for BK/C520-125MA?

A: No compatibility concerns exist. Both parts are manufactured by Eaton - Electronics Division within the C520 series and share identical electrical characteristics, thermal properties, and physical dimensions. The BK/C520-125-R will function identically in any circuit designed for the BK/C520-125MA.

Q: Does the BK/C520-125-R require a different holder or mounting configuration?

A: No. Both parts use the 2AG cartridge form factor (5mm x 15mm) and require the same holder type. Existing fuse holders designed for the BK/C520-125MA will accommodate the BK/C520-125-R without modification.

Q: Why should I choose BK/C520-125-R over BK/C520-125MA?

A: The BK/C520-125-R should be selected because it is an active product with current manufacturing support and improved regulatory compliance (RoHS3, REACH unaffected). The BK/C520-125MA is obsolete and may face supply constraints. The BK/C520-125-R provides identical circuit protection performance with enhanced environmental compliance.

Q: Are the certifications identical between both parts?

A: Both parts carry CSA and UL certifications, meeting the same safety standards. The BK/C520-125-R additionally meets RoHS3 and REACH requirements, providing broader regulatory alignment for applications with environmental compliance mandates.