BK/C520-4A Equivalent & Substitute Parts

Part Overview

The BK/C520-4A is a 4 A, 250 V AC/DC fast-blow glass cartridge fuse manufactured by Eaton - Electronics Division. This component is classified as obsolete and requires a fuse holder for installation. The 2AG form factor (5mm x 15mm) is a standard industrial fuse package. Due to its obsolete product status, identifying active equivalent parts is necessary for ongoing system maintenance and new design implementations.

Substiute Parts

BK/C520-4A

Eaton - Electronics DivisionIn Stock: 1163BK/C520-4A Datasheet

Current PartRFQ

BK/C520-4-R

Eaton - Electronics DivisionIn Stock: 725BK/C520-4-R Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BK/C520-4A is based on strict electrical and mechanical parameter matching within the 2AG glass cartridge fuse category. The following parameters determine substitutability:

• Current Rating: Must be 4 A
• Voltage Rating (AC): Must be 250 V
• Fuse Type: Must be Cartridge, Glass
• Package / Case: Must be 2AG, 5mm x 15mm
• Response Time: Must be Fast Blow
• Breaking Capacity @ Rated Voltage: Must be 200 A
• Melting I²t: Must be 16.6
• DC Cold Resistance: Must be 0.022 Ohms
• Approval Agency: Must include CSA and UL certifications

The BK/C520-4-R meets all these criteria and is classified as an active product, making it a direct electrical and mechanical equivalent.

Parameter Comparison

Engineering Selection Recommendations

The BK/C520-4-R is the direct equivalent for the obsolete BK/C520-4A. Both parts are manufactured by Eaton - Electronics Division and share identical electrical and mechanical specifications across all critical parameters: 4 A current rating, 250 V AC voltage rating, fast-blow response, 2AG form factor, 200 A breaking capacity, and CSA/UL certifications.

The primary distinction is product status: BK/C520-4A is obsolete, while BK/C520-4-R is active. Additionally, BK/C520-4-R achieves ROHS3 compliance, whereas BK/C520-4A is non-compliant. For new designs or system replacements, BK/C520-4-R is the appropriate selection. Both parts require a compatible 2AG fuse holder for installation.

Frequently Asked Questions (FAQ)

Q: Can BK/C520-4-R be used as a direct replacement for BK/C520-4A?

A: Yes. Both parts are identical in electrical performance and mechanical form factor. All critical parameters—current rating, voltage rating, response time, breaking capacity, melting I²t, and resistance—are equivalent. Both are certified by CSA and UL.

Q: What is the difference between BK/C520-4A and BK/C520-4-R?

A: The primary differences are product status and RoHS compliance. BK/C520-4A is obsolete and RoHS non-compliant. BK/C520-4-R is active and ROHS3 compliant. Electrically and mechanically, they are identical.

Q: Are these fuses interchangeable in existing equipment?

A: Yes, provided the equipment uses a standard 2AG fuse holder. Both parts have identical dimensions (5mm x 15mm) and electrical characteristics. No holder modification is required.

Q: What does "Fast Blow" mean for these fuses?

A: Fast Blow indicates the fuse responds quickly to overcurrent conditions. The melting I²t value of 16.6 defines the thermal energy threshold at which the fuse element melts and interrupts the circuit.

Q: Why is RoHS compliance important?

A: RoHS3 compliance indicates the part meets current environmental and material restriction standards. For new designs or regulated applications, ROHS3-compliant parts are preferred. BK/C520-4-R meets this requirement.

Q: What is the breaking capacity specification?

A: The 200 A breaking capacity at rated voltage indicates the maximum fault current the fuse can safely interrupt without rupturing or creating a hazard. Both parts have identical breaking capacity.

Q: Do these fuses require a specific holder?

A: Yes. Both BK/C520-4A and BK/C520-4-R require a 2AG fuse holder. The holder provides electrical contact and mechanical retention for the cartridge fuse.