Littelfuse 021501.6H Ceramic Fuse - Equivalent & Substitute Parts

Part Overview

The Littelfuse 021501.6H is a 1.6 A, 250 V AC ceramic cartridge fuse in 5mm x 20mm form factor, designed for circuit protection in applications requiring slow-blow response characteristics. This part is classified as obsolete, making identification of active equivalent and substitute parts essential for ongoing design support and procurement continuity. Substitute parts must maintain identical electrical ratings, mechanical dimensions, and functional performance to ensure direct compatibility in existing circuit designs.

Key Parameters

Parameter	Specification
Current Rating	1.6 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Ceramic
Response Time	Slow Blow
Package / Case	5mm x 20mm
Breaking Capacity	1.5 kA @ Rated Voltage
Mounting Type	Requires Holder
Operating Temperature Range	-55°C to 125°C

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following critical parameters:

Current Rating: 1.6 A (exact match required)
Voltage Rating (AC): 250 V (exact match required)
Fuse Type: Cartridge, Ceramic (exact match required)
Response Time: Slow Blow (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Breaking Capacity: 1.5 kA @ Rated Voltage (exact match required)
Mounting Type: Requires Holder (exact match required)

All substitute parts listed below meet these criteria and are classified as active products with current manufacturing status, ensuring long-term availability and supply chain reliability.

Parameter Comparison

Part Number	Manufacturer	Current Rating (A)	Voltage AC (V)	Voltage DC (V)	Response Time	Package	Breaking Capacity (kA)	Melting I²t	DC Cold Resistance (Ω)	Product Status	RoHS Status
021501.6H	Littelfuse Inc.	1.6	250	—	Slow Blow	5mm x 20mm	1.5	3.9	0.0588	Obsolete	RoHS Non-Compliant
021501.6HXP	Littelfuse Inc.	1.6	250	—	Slow Blow	5mm x 20mm	1.5	6.83	0.0707	Active	ROHS3 Compliant
0001.2506	SCHURTER Inc.	1.6	250	300	Slow Blow	5mm x 20mm	1.5	4.35	—	Active	ROHS3 Compliant
5HT 1.6-R	Bel Fuse Inc.	1.6	250	—	Slow Blow	5mm x 20mm	1.5	5.4	0.1	Active	ROHS3 Compliant
BK/S505-1.6-R	Eaton - Electronics Division	1.6	250	—	Slow Blow	5mm x 20mm	1.5	6.78	0.07	Active	RoHS Compliant
S505-1.6-R	Eaton - Electronics Division	1.6	250	—	Slow Blow	5mm x 20mm	1.5	6.78	0.07	Active	RoHS Compliant

Engineering Selection Recommendations

Direct Replacement (Littelfuse Ecosystem): The 021501.6HXP is the active equivalent from the original manufacturer, Littelfuse Inc. This part maintains identical electrical and mechanical specifications while offering ROHS3 compliance and improved supply availability. Selection of this part eliminates cross-manufacturer qualification requirements.

Multi-Manufacturer Alternatives: The SCHURTER 0001.2506, Bel Fuse 5HT 1.6-R, and Eaton S505-1.6-R / BK/S505-1.6-R parts are functionally equivalent substitutes. All are active products with established certifications (CCC, CSA, cURus, KC, PSE, VDE, UL). The SCHURTER part offers extended DC voltage rating (300 V DC) for applications requiring dual-voltage protection. Eaton parts provide identical melting I²t characteristics (6.78) and are available in higher inventory quantities.

Compliance Considerations: All substitute parts are ROHS3 compliant or RoHS compliant, addressing regulatory requirements for new designs. The original 021501.6H is RoHS non-compliant and should not be specified for new applications subject to RoHS directives.

Frequently Asked Questions (FAQ)

Q: Can the 021501.6HXP directly replace the obsolete 021501.6H?

A: Yes. The 021501.6HXP is the active Littelfuse equivalent with identical current rating (1.6 A), voltage rating (250 V AC), response time (Slow Blow), and package dimensions (5mm x 20mm). It is the recommended replacement for the obsolete part.

Q: What is the difference between the Littelfuse 021501.6HXP and the SCHURTER 0001.2506?

A: Both parts meet the core substitution criteria. The SCHURTER 0001.2506 provides additional DC voltage rating (300 V DC) compared to the Littelfuse part, which specifies AC only. This makes the SCHURTER part suitable for applications requiring dual-voltage protection. Melting I²t values differ slightly (6.83 vs. 4.35), reflecting different thermal response profiles within the slow-blow classification.

Q: Are the Eaton S505-1.6-R and BK/S505-1.6-R interchangeable?

A: Yes. Both parts are from the Eaton S505 series with identical electrical specifications, breaking capacity, melting I²t (6.78), and DC cold resistance (0.07 Ω). They differ only in packaging designation and are functionally equivalent.

Q: What certifications apply to all substitute parts?

A: All substitute parts carry multiple international certifications including CCC, CSA, cURus, KC, PSE, and VDE. The Littelfuse 021501.6HXP and SCHURTER 0001.2506 include CE marking. Eaton parts include BSI and IMQ certifications. Verify specific certification requirements for your application region before final selection.

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

A: Yes. All substitute parts maintain the 5mm x 20mm cartridge form factor and require a compatible fuse holder. Mechanical interchangeability is guaranteed across all listed parts.

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

A: Melting I²t values (ranging from 3.9 to 6.83 across the part list) indicate thermal energy absorption before fuse element melting. While all parts are classified as slow-blow, variations in I²t reflect different internal fuse element designs. For applications with specific thermal response requirements, consult detailed fuse characteristic curves from the manufacturer.

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