Equivalent & Substitute Parts for BK/C520-3.5A

Part Overview

The BK/C520-3.5A is a 3.5 A 250 V AC DC glass cartridge fuse manufactured by Eaton - Electronics Division. This component is classified as obsolete, requiring identification of active equivalent and substitute parts for ongoing system maintenance and new designs. The 2AG form factor (5mm x 15mm) with fast-blow response characteristics defines the functional requirements for substitution.

Key Parameters

Parameter	Value
Current Rating	3.5 A
Voltage Rating - AC	250 V
Fuse Type	Cartridge, Glass
Package / Case	2AG, 5mm x 15mm
Response Time	Fast Blow
Breaking Capacity @ Rated Voltage	100A
Mounting Type	Requires Holder

Substitute Part Grouping Explanation

Substitution for the BK/C520-3.5A is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Current Rating: 3.5 A (exact match required)
Voltage Rating - AC: 250 V (exact match required)
Package / Case: 2AG, 5mm x 15mm (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Fast Blow (exact match required)
Mounting Type: Requires Holder (exact match required)

Substitute Parts Identified:

Group 1 - Direct Eaton Equivalent:

BK/C520-3.5-R (Eaton - Electronics Division, Active status)

Group 2 - Littelfuse Cross-Compatibility:

022503.5HXP (Littelfuse, Active status)
022503.5MXP (Littelfuse, Active status)
022503.5VXP (Littelfuse Inc., Active status)

All substitute parts maintain identical current rating, AC voltage rating, package dimensions, fuse type, and response characteristics. Littelfuse variants provide additional DC voltage rating (125 V DC) and extended operating temperature range (-55°C ~ 125°C) not specified for the original part.

Parameter Comparison

Parameter	BK/C520-3.5A	BK/C520-3.5-R	022503.5HXP	022503.5MXP	022503.5VXP
Manufacturer	Eaton	Eaton	Littelfuse	Littelfuse	Littelfuse Inc.
Current Rating (Amps)	3.5 A	3.5 A	3.5 A	3.5 A	3.5 A
Voltage Rating - AC	250 V	250 V	250 V	250 V	250 V
Voltage Rating - DC	Not specified	Not specified	125 V	125 V	125 V
Fuse Type	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass
Package / Case	2AG, 5mm x 15mm	2AG, 5mm x 15mm	2AG, 5mm x 15mm	2AG, 5mm x 15mm	2AG, 5mm x 15mm
Response Time	Fast Blow	Fast Blow	Fast Blow	Fast Blow	Fast Blow
Breaking Capacity @ Rated Voltage	100A	100A	100A AC, 10kA DC	100A AC, 10kA DC	100A AC, 10kA DC
Melting I²t	9.7	9.7	6.7	6.7	6.7
DC Cold Resistance (Ohms)	0.032	0.032	0.0265	0.0265	0.0265
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	CSA, UL	CSA, UL	CE, CSA, PSE, UL	CE, CSA, PSE, UL	CE, CSA, PSE, UL

Engineering Selection Recommendations

For Direct Replacement (Preferred): BK/C520-3.5-R is the primary substitute, maintaining identical electrical characteristics and mechanical form factor while offering active product status and ROHS3 compliance. This part is sourced from the original manufacturer (Eaton) and ensures continuity of design specifications.

For Extended Capability Applications: The Littelfuse variants (022503.5HXP, 022503.5MXP, 022503.5VXP) provide additional design flexibility through DC voltage rating (125 V) and extended operating temperature range (-55°C ~ 125°C). These parts are suitable for applications requiring enhanced environmental performance or dual AC/DC operation. All three Littelfuse options meet CE, CSA, PSE, and UL certifications, exceeding the original part's approval scope.

Compliance Considerations: All substitute parts are ROHS3 compliant, addressing regulatory requirements not met by the obsolete BK/C520-3.5A. The Littelfuse variants include REACH Unaffected status, providing additional environmental compliance documentation.

Frequently Asked Questions (FAQ)

Q: Can BK/C520-3.5-R be used as a direct replacement for BK/C520-3.5A? A: Yes. BK/C520-3.5-R maintains identical current rating (3.5 A), AC voltage rating (250 V), package dimensions (2AG, 5mm x 15mm), fuse type (cartridge glass), response time (fast blow), and breaking capacity (100A). The primary difference is product status (active versus obsolete) and RoHS compliance.

Q: What is the difference between Littelfuse 022503.5HXP, 022503.5MXP, and 022503.5VXP? A: These three Littelfuse parts are electrically and mechanically identical. All share the same current rating (3.5 A), AC voltage rating (250 V), DC voltage rating (125 V), package (2AG, 5mm x 15mm), response time (fast blow), and certifications. Differences exist only in part numbering and inventory availability.

Q: Are the Littelfuse parts compatible with existing 2AG fuse holders? A: Yes. All substitute parts use the 2AG form factor (5mm x 15mm) and require a holder, maintaining mechanical compatibility with existing installations designed for the BK/C520-3.5A.

Q: What is the significance of the melting I²t difference between Eaton and Littelfuse parts? A: The BK/C520-3.5A and BK/C520-3.5-R have melting I²t of 9.7, while Littelfuse variants have 6.7. This indicates faster thermal response in Littelfuse parts under fault conditions. Both values are within the 3.5 A fast-blow fuse category and maintain the same current rating and breaking capacity.

Q: Can these fuses be used in DC applications? A: The BK/C520-3.5A and BK/C520-3.5-R are rated for AC operation only. Littelfuse variants (022503.5HXP, 022503.5MXP, 022503.5VXP) are rated for both AC (250 V) and DC (125 V) operation, making them suitable for dual-voltage applications.

Q: What certifications apply to these substitute parts? A: BK/C520-3.5A and BK/C520-3.5-R carry CSA and UL approvals. Littelfuse variants carry CE, CSA, PSE, and UL approvals, providing broader international compliance coverage.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message