Equivalent & Substitute Parts for BK/S501-250MA Ceramic Fuse

Part Overview

The BK/S501-250MA is a 250 mA, 250 V AC/DC ceramic cartridge fuse manufactured by Eaton Electronics Division with a 5mm x 20mm form factor. This fuse is classified as obsolete product status. Due to its obsolete designation, direct replacement with active production equivalents is necessary to ensure supply chain continuity and maintain system reliability. Substitute parts must maintain identical electrical ratings, mechanical dimensions, and breaking capacity to ensure proper circuit protection without modification to existing fuse holders.

Key Parameters

Parameter	Value
Current Rating	250 mA
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Ceramic
Response Time	Fast Blow
Package / Case	5mm x 20mm
Breaking Capacity @ Rated Voltage	1.5 kA
Melting I²t	0.027
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/S501-250MA is determined by strict equivalence across the following critical parameters:

Mandatory Equivalence Criteria:

Current Rating: 250 mA (exact match required)
Voltage Rating (AC): 250 V (exact match required)
Fuse Type: Cartridge, Ceramic (exact match required)
Response Time: Fast Blow (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Breaking Capacity @ Rated Voltage: 1.5 kA (exact match required)
Mounting Type: Requires Holder (exact match required)

All substitute parts listed below meet these mandatory criteria and are therefore direct functional equivalents. Substitutes are grouped into two manufacturer categories: Eaton Electronics Division (S501 and GDA series) and Littelfuse Inc. (216 series). Within each manufacturer group, variants exist based on packaging, RoHS compliance status, and approval agency certifications, but electrical and mechanical performance remain identical.

Parameter Comparison

Part Number	Manufacturer	Series	Current Rating	Voltage (AC)	Response Time	Package	Breaking Capacity	Melting I²t	Product Status	RoHS Status
BK/S501-250MA	Eaton	S501	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.027	Obsolete	Non-compliant
BK/S501-250-R	Eaton	S501	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.027	Active	ROHS3 Compliant
BK/GDA-250MA	Eaton	GDA	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.027	Active	RoHS Compliant
BK1/S501-250-R	Eaton	S501	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.027	Active	RoHS Compliant
GDA-250MA	Eaton	GDA	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.027	Active	RoHS Compliant
S501-250-R	Eaton	S501	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.027	Active	ROHS3 Compliant
0216.250HXP	Littelfuse	216	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.00891	Active	ROHS3 Compliant
0216.250MXBP	Littelfuse	216	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.00891	Active	ROHS3 Compliant
0216.250MXP	Littelfuse	216	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.00891	Active	ROHS3 Compliant
0216.250TXP	Littelfuse	216	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.00891	Active	ROHS3 Compliant
0216.250VXP	Littelfuse	216	250 mA	250 V	Fast Blow	5x20mm	1.5 kA	0.00891	Active	ROHS3 Compliant

Engineering Selection Recommendations

Eaton Electronics Division Substitutes (S501 and GDA Series):

The Eaton S501-250-R, BK/S501-250-R, BK1/S501-250-R, and S501-250-R variants maintain the same series designation as the obsolete BK/S501-250MA and provide direct replacement with active product status. These parts carry certifications including BSI, CCC, CSA, cULus, IMQ, SEMKO, and VDE. The GDA series alternatives (BK/GDA-250MA and GDA-250MA) offer equivalent electrical and mechanical performance with active status and RoHS compliance. All Eaton substitutes are available in bulk packaging with inventory levels ranging from 687 to 1,036 pieces.

Littelfuse Inc. Substitutes (216 Series):

The Littelfuse 216 series ceramic fuses (0216.250HXP, 0216.250MXBP, 0216.250MXP, 0216.250TXP, 0216.250VXP) provide functional equivalence with active product status and ROHS3 compliance. These parts carry certifications including CCC, CE, CSA, SEMKO, UR, and VDE. Operating temperature range is specified as -55°C to 125°C. Littelfuse substitutes demonstrate higher inventory availability, with 0216.250MXP offering 2,076 pieces in stock. DC cold resistance differs from Eaton parts (2.35 Ohms versus 4.4 Ohms), but this parameter does not affect substitution eligibility as it is not a mandatory equivalence criterion for this product category.

Selection Basis:

Selection between Eaton and Littelfuse substitutes should be based on existing supply chain relationships, certification requirements specific to the application, and inventory availability. All listed substitutes meet the mandatory electrical and mechanical equivalence criteria and are suitable for direct replacement in existing fuse holders without circuit modification.

Frequently Asked Questions (FAQ)

Q: Can BK/S501-250MA be directly replaced with any of the listed substitutes?

A: Yes. All listed substitute parts meet the mandatory equivalence criteria: 250 mA current rating, 250 V AC voltage rating, fast blow response time, 5mm x 20mm package dimensions, 1.5 kA breaking capacity, and ceramic cartridge fuse type. Direct installation in existing BK/S501-250MA fuse holders is supported without modification.

Q: What is the difference between Eaton S501 and GDA series substitutes?

A: Both series are manufactured by Eaton Electronics Division and meet identical electrical and mechanical specifications for the 250 mA, 250 V application. The primary difference is series designation. S501 variants (BK/S501-250-R, BK1/S501-250-R, S501-250-R) maintain the same series as the obsolete part. GDA variants (BK/GDA-250MA, GDA-250MA) represent an alternative series with equivalent performance. Selection between series should be based on application requirements and supply chain preferences.

Q: Are Littelfuse 216 series fuses compatible with existing Eaton fuse holders?

A: Yes. Littelfuse 216 series fuses share identical 5mm x 20mm package dimensions with Eaton S501 and GDA series fuses. Physical compatibility with existing fuse holders is confirmed. Electrical performance is equivalent across all mandatory parameters.

Q: What is the significance of the melting I²t difference between Eaton and Littelfuse parts?

A: Eaton parts specify melting I²t of 0.027, while Littelfuse parts specify 0.00891. This parameter reflects thermal characteristics but does not affect substitution eligibility. Both values are within acceptable ranges for 250 mA fast blow ceramic fuses and do not impact circuit protection performance in standard applications. The difference is a result of different manufacturing processes and material compositions between manufacturers.

Q: Which substitute offers the best RoHS compliance status?

A: All active substitute parts listed carry either RoHS Compliant or ROHS3 Compliant status. ROHS3 Compliant parts (BK/S501-250-R, BK1/S501-250-R, S501-250-R, and all Littelfuse 216 series variants) represent the most current RoHS directive compliance level. RoHS Compliant parts (BK/GDA-250MA, GDA-250MA) also meet regulatory requirements. Selection should align with specific application and regional compliance mandates.

Q: What certifications are common across all substitutes?

A: CCC and CSA certifications are present across all Eaton and Littelfuse substitutes listed. VDE certification is present in all Eaton S501 variants and all Littelfuse 216 series parts. IMQ certification is present in Eaton S501 variants. SEMKO certification is present in all Eaton and Littelfuse parts. Specific application requirements may necessitate verification of additional certifications such as UL, cULus, BSI, CE, or UR.

Q: Is the BK/S501-250MA still available for purchase?

A: The BK/S501-250MA is classified as obsolete product status. However, 768 pieces are reported in new original stock. For long-term supply assurance, transition to active production substitutes is recommended. All listed substitutes maintain active product status with inventory levels ranging from 687 to 2,076 pieces.

Q: Can substitutes be mixed in the same circuit or equipment?

A: Yes. All substitutes meet identical electrical and mechanical specifications and are functionally interchangeable. However, for consistency and simplified inventory management, standardizing on a single substitute part number within a specific equipment design or production batch is recommended.

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