BK/S504-63MA Equivalent & Substitute Parts

Part Overview

The BK/S504-63MA is a 63 mA, 250 V AC/DC slow-blow glass cartridge fuse in a 5mm x 20mm package manufactured by Eaton - Electronics Division. This component is classified as obsolete, requiring identification of active equivalent and substitute parts for ongoing circuit protection applications. The fuse requires a holder for installation and is designed for applications demanding time-delayed response characteristics. Locating functionally equivalent alternatives is necessary to maintain design continuity and ensure supply chain availability for new production and field replacements.

Key Parameters

Parameter	Value
Current Rating	63 mA
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Package / Case	5mm x 20mm
Response Time	Slow Blow
Breaking Capacity @ Rated Voltage	35 A
Mounting Type	Requires Holder

Substitute Part Grouping Explanation

Substitution eligibility for the BK/S504-63MA is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

Current Rating: 63 mA
Voltage Rating (AC): 250 V
Fuse Type: Cartridge, Glass
Package / Case: 5mm x 20mm
Response Time: Slow Blow
Breaking Capacity @ Rated Voltage: 35 A
Mounting Type: Requires Holder

Parts are classified as Parametric Equivalents when all mandatory parameters match exactly. Parts are classified as Similar when all mandatory parameters match but secondary characteristics such as melting I²t, DC cold resistance, or approval agencies differ. All identified substitutes meet the core electrical and mechanical requirements for direct replacement in the circuit protection function.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Series	Current Rating (mA)	Voltage (V AC)	Package	Response Time	Breaking Capacity (A)	Product Status	RoHS Status
BK/S504-63MA	Eaton - Electronics Division	S504	63	250	5mm x 20mm	Slow Blow	35	Obsolete	Non-compliant
BK/GDC-63MA	Eaton - Electronics Division	GDC	63	250	5mm x 20mm	Slow Blow	35	Active	Compliant
BK1/S506-63-R	Eaton - Electronics Division	S506	63	250	5mm x 20mm	Slow Blow	35	Active	ROHS3 Compliant
GDC-63MA	Eaton - Electronics Division	GDC	63	250	5mm x 20mm	Slow Blow	35	Active	Not specified
S506-63-R	Eaton - Electronics Division	S506	63	250	5mm x 20mm	Slow Blow	35	Active	ROHS3 Compliant
0034.3105	SCHURTER Inc.	FST 5x20	63	250	5mm x 20mm	Slow Blow	35	Active	ROHS3 Compliant
0218.063HXP	Littelfuse Inc.	218	63	250	5mm x 20mm	Slow Blow	35	Active	ROHS3 Compliant
0034.5031	SCHURTER Inc.	FTT 5x20	63	250	5mm x 20mm	Slow Blow	35	Active	ROHS3 Compliant
0034.5605.11	SCHURTER Inc.	SMD-FST	63	250	5mm x 20mm	Slow Blow	35	Active	ROHS3 Compliant
0218.063MXGP	Littelfuse Inc.	218	63	250	5mm x 20mm	Slow Blow	35	Active	ROHS3 Compliant
0218.063MXP	Littelfuse Inc.	218	63	250	5mm x 20mm	Slow Blow	35	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation - Eaton Equivalents:

The BK/GDC-63MA, BK1/S506-63-R, GDC-63MA, and S506-63-R are parametric equivalents manufactured by Eaton - Electronics Division. These parts maintain identical electrical and mechanical specifications to the BK/S504-63MA. The S506 series variants (BK1/S506-63-R and S506-63-R) carry ROHS3 compliance and broader approval agency certifications including BSI, CCC, CSA, IMQ, SEMKO, UR, and VDE. The GDC series variants (BK/GDC-63MA and GDC-63MA) are active products with RoHS compliance and cULus/IMQ approvals. Selection between these Eaton options depends on specific regulatory requirements and approval agency mandates for the target application.

Secondary Recommendations - Multi-Manufacturer Equivalents:

SCHURTER Inc. and Littelfuse Inc. offer parametric equivalents meeting all mandatory electrical and mechanical parameters. SCHURTER products include 0034.3105 (FST 5x20 series), 0034.5031 (FTT 5x20 series), and 0034.5605.11 (SMD-FST series). Littelfuse products include 0218.063HXP, 0218.063MXGP, and 0218.063MXP (all 218 series). All multi-manufacturer alternatives are ROHS3 compliant and carry active product status. Selection among these alternatives depends on approval agency requirements specific to the end application and regional regulatory compliance mandates.

Compliance Considerations:

The original BK/S504-63MA is RoHS non-compliant. All identified active substitutes are RoHS3 compliant, supporting modern design requirements. Approval agency certifications vary across manufacturers and series. Applications requiring specific certifications (UL, VDE, CSA, CCC, etc.) must select substitutes carrying the required approvals.

Frequently Asked Questions (FAQ)

Q: Can the BK/S504-63MA be directly replaced with any of the listed substitutes?

A: Yes. All listed substitutes are parametric or similar equivalents meeting the mandatory electrical and mechanical specifications: 63 mA current rating, 250 V AC voltage rating, 5mm x 20mm package, slow-blow response, 35 A breaking capacity, and cartridge glass fuse type requiring a holder. Direct physical and electrical replacement is supported.

Q: What is the difference between "Parametric Equivalent" and "Similar" classifications?

A: Parametric Equivalents match all mandatory electrical and mechanical parameters exactly. Similar parts match all mandatory parameters but differ in secondary characteristics such as melting I²t, DC cold resistance, or approval agency certifications. Both classifications support functional replacement in circuit protection applications.

Q: Are there differences in approval agencies among the substitutes?

A: Yes. The original BK/S504-63MA carries BSI, IMQ, SEMKO, UL, and VDE approvals. Eaton S506 series variants carry BSI, CCC, CSA, IMQ, SEMKO, UR, and VDE approvals. Eaton GDC series variants carry cULus and IMQ approvals. SCHURTER and Littelfuse products carry varying combinations of CCC, CE, CSA, cURus, K-MARK, KC, SEMKO, UL, and VDE approvals. Selection must align with application-specific regulatory requirements.

Q: Does the 5mm x 20mm package dimension apply to all substitutes?

A: Yes. All identified substitutes use the 5mm x 20mm cartridge glass fuse package and require a holder for installation. Physical compatibility with existing fuse holders is maintained across all substitutes.

Q: What is the significance of the melting I²t parameter variation among substitutes?

A: Melting I²t represents the thermal energy required to melt the fuse element. The original BK/S504-63MA specifies 0.012 I²t. Most active substitutes specify 0.021 I²t, while some Littelfuse variants specify 0.0117 I²t and SCHURTER variants range from 0.037 to 0.0401 I²t. These variations reflect different fuse element designs within the same 63 mA slow-blow classification. All values support the slow-blow response characteristic and 35 A breaking capacity.

Q: Is the BK/S504-63MA still available for purchase?

A: The BK/S504-63MA is classified as obsolete. However, 1121 pieces are reported in stock as new original inventory. For new designs and long-term supply assurance, selection of an active substitute from the Eaton S506, Eaton GDC, SCHURTER, or Littelfuse product lines is recommended.

Q: What is the operating temperature range for these fuses?

A: The original BK/S504-63MA does not specify an operating temperature range. Eaton GDC and S506 series variants do not specify operating temperature ranges. SCHURTER 0034.3105 and 0034.5605.11 specify -55°C to 125°C. SCHURTER 0034.5031 specifies -40°C to 85°C. Littelfuse 218 series variants specify -55°C to 125°C. Application-specific temperature requirements should guide substitute selection when operating temperature range is a design constraint.

Q: Are all substitutes RoHS compliant?

A: No. The original BK/S504-63MA is RoHS non-compliant. All identified active substitutes are ROHS3 compliant. For applications requiring RoHS compliance, any of the active substitutes listed in this reference are suitable.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message