Equivalent & Substitute Parts for BK/S505-8A Ceramic Fuse

Part Overview

The BK/S505-8A is an 8 A, 250 V AC ceramic cartridge fuse manufactured by Eaton - Electronics Division in the S505 series. This fuse is designed for 5mm x 20mm holder applications and features slow-blow response characteristics. The part is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain electrical and mechanical compatibility for continued circuit protection applications.

Key Parameters

Parameter	Value
Current Rating	8 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Ceramic
Package / Case	5mm x 20mm
Response Time	Slow Blow
Breaking Capacity @ Rated Voltage	1.5 kA
Mounting Type	Requires Holder
Size / Dimension	0.205" Dia x 0.787" L (5.20mm x 20.00mm)

Substitute Part Grouping Explanation

Substitution eligibility for the BK/S505-8A is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Current Rating: 8 A (exact match required)
Voltage Rating (AC): 250 V (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Fuse Type: Cartridge, Ceramic (exact match required)
Response Time: Slow Blow (exact match required)
Mounting Type: Requires Holder (exact match required)

Secondary Compatibility Parameters:

Breaking Capacity @ Rated Voltage: 1.5 kA (preferred match)
Melting I²t: 209.88 to 311 (acceptable range for slow-blow ceramic cartridges)

All substitute parts listed meet these primary criteria. Variations in melting I²t values within the acceptable range reflect manufacturing tolerances and design variations between manufacturers while maintaining functional equivalence for circuit protection.

Parameter Comparison

Part Number	Manufacturer	Current (A)	Voltage AC (V)	Voltage DC (V)	Package	Response Time	Breaking Capacity	Melting I²t	Product Status	RoHS Status
BK/S505-8A	Eaton	8	250	—	5x20mm	Slow Blow	1.5 kA	311	Obsolete	Non-compliant
BK/S505-8-R	Eaton	8	250	—	5x20mm	Slow Blow	1.5 kA	228	Active	ROHS3 Compliant
BK1/S505-8-R	Eaton	8	250	—	5x20mm	Slow Blow	1.5 kA	228	Active	ROHS3 Compliant
S505-8-R	Eaton	8	250	—	5x20mm	Slow Blow	1.5 kA	228	Active	RoHS Compliant
0001.2513	SCHURTER	8	250	150	5x20mm	Slow Blow	1 kA AC / 1.5 kA DC	268	Active	ROHS3 Compliant
0001.2713.11	SCHURTER	8	250	150	5x20mm	Slow Blow	1 kA AC / 1.5 kA DC	268	Active	ROHS3 Compliant
0215008.HXP	Littelfuse	8	250	—	5x20mm	Slow Blow	1.5 kA	209.88	Active	ROHS3 Compliant
0215008.MXBP	Littelfuse	8	250	—	5x20mm	Slow Blow	1.5 kA	209.88	Active	ROHS3 Compliant
0215008.MXGP	Littelfuse	8	250	—	5x20mm	Slow Blow	1.5 kA	209.88	Active	ROHS3 Compliant
0215008.MXP	Littelfuse	8	250	—	5x20mm	Slow Blow	1.5 kA	209.88	Active	ROHS3 Compliant
0215008.TXP	Littelfuse	8	250	—	5x20mm	Slow Blow	1.5 kA	209.88	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Manufacturer Equivalents (Eaton S505 Series):

The BK/S505-8-R, BK1/S505-8-R, and S505-8-R represent direct Eaton equivalents with active product status. These parts maintain identical electrical specifications and mechanical form factor. All three variants are RoHS compliant, addressing regulatory requirements absent in the obsolete BK/S505-8A. Selection among these three Eaton variants depends on packaging requirements and regional certification needs.

Cross-Manufacturer Alternatives (SCHURTER SPT Series):

The SCHURTER parts 0001.2513 and 0001.2713.11 provide functional equivalence with extended DC voltage rating (150 V DC) and broader operating temperature range (-55°C to 125°C). These components are suitable for applications requiring dual AC/DC voltage specifications. Breaking capacity differs (1 kA AC / 1.5 kA DC) compared to the 1.5 kA AC rating of the original part.

Cross-Manufacturer Alternatives (Littelfuse 215 Series):

The Littelfuse parts 0215008.HXP, 0215008.MXBP, 0215008.MXGP, 0215008.MXP, and 0215008.TXP provide electrical and mechanical equivalence with active product status and ROHS3 compliance. These components feature lower melting I²t values (209.88) compared to the original specification (311), reflecting design optimization within acceptable slow-blow ceramic cartridge parameters. Operating temperature range extends to -55°C to 125°C.

Compliance Considerations:

All substitute parts listed are ROHS3 compliant or RoHS compliant, addressing environmental regulatory requirements. Approval agencies vary by manufacturer and regional market; selection should align with target application certifications (UL, CSA, VDE, etc.).

Frequently Asked Questions (FAQ)

Q: Can I substitute the obsolete BK/S505-8A with any of the listed parts?

A: All listed parts meet the primary substitution criteria: 8 A current rating, 250 V AC voltage rating, 5mm x 20mm package, ceramic cartridge type, slow-blow response, and holder-mount configuration. Direct substitution is electrically and mechanically valid for all listed alternatives.

Q: What is the difference between Eaton variants BK/S505-8-R, BK1/S505-8-R, and S505-8-R?

A: All three are Eaton S505 series active equivalents with identical electrical specifications. Differences relate to packaging designation and regional certification scope. BK1/S505-8-R includes broader international certifications (CCC/CQC, cURus). Selection depends on specific certification requirements for the target application.

Q: Why do SCHURTER parts have both AC and DC voltage ratings?

A: SCHURTER 0001.2513 and 0001.2713.11 are designed for dual-voltage applications, rated 250 V AC and 150 V DC. These parts are suitable for circuits requiring DC protection capability. The original BK/S505-8A specifies AC voltage only. Use SCHURTER parts only if DC voltage protection is required or acceptable for the application.

Q: How do melting I²t values affect substitution?

A: Melting I²t indicates thermal energy required to melt the fuse element. The original BK/S505-8A specifies 311, while substitutes range from 209.88 to 268. All values fall within acceptable parameters for 8 A slow-blow ceramic cartridges. Lower I²t values indicate faster thermal response; higher values indicate slower response. Selection should confirm compatibility with circuit protection requirements.

Q: Are all substitute parts RoHS compliant?

A: All listed substitute parts are RoHS compliant (ROHS3 or RoHS designation). The original BK/S505-8A is RoHS non-compliant. Substitution with any listed part addresses RoHS regulatory requirements.

Q: What certifications should I verify for my specific application?

A: Certification requirements depend on target market and application. Eaton parts carry BSI, CSA, IMQ, SEMKO, UL, VDE approvals. SCHURTER parts carry cURus and VDE approvals. Littelfuse parts carry CE, CSA, KC, PSE, SEMKO, UL, VDE approvals. Confirm that the selected substitute part includes certifications required by your application standards and regional regulations.

Q: Can I use Littelfuse parts as direct replacements in existing Eaton fuse holders?

A: Yes. All substitute parts share identical 5mm x 20mm package dimensions and holder-mount configuration. Littelfuse 215 series parts are mechanically and electrically compatible with Eaton S505 series holders.

Q: What is the difference between 0215008.MXP and other Littelfuse variants?

A: All Littelfuse 215 series variants (0215008.HXP, 0215008.MXBP, 0215008.MXGP, 0215008.MXP, 0215008.TXP) share identical electrical specifications and melting I²t values (209.88). Designations reflect internal Littelfuse product line variations and packaging configurations. Selection among variants depends on availability and specific procurement requirements.

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