Equivalent & Substitute Parts for S506-1.6-R Glass Cartridge Fuse

Part Overview

The Eaton S506-1.6-R is a 1.6 A, 250 V AC/DC glass cartridge fuse in 5mm x 20mm package format, classified as a slow-blow fuse requiring a holder for installation. This component is Active in product status and complies with multiple international safety standards including BSI, CCC, CSA, CURUS, IMQ, PSE/JET, SEMKO, and VDE. Alternative equivalent parts become necessary when primary stock is unavailable, when specific approval certifications are required for regional compliance, or when application-specific electrical characteristics such as breaking capacity or melting I²t values must be optimized for circuit protection requirements.

Key Parameters

Parameter	Value	Unit
Current Rating	1.6	A
Voltage Rating (AC)	250	V
Fuse Type	Cartridge, Glass	—
Package / Case	5mm x 20mm	—
Response Time	Slow Blow	—
Mounting Type	Requires Holder	—
Breaking Capacity @ Rated Voltage	35	A
Melting I²t	21.7	—
DC Cold Resistance	0.0425	Ohms
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the S506-1.6-R is determined by strict equivalence across the following mandatory parameters:

Primary Equivalence Criteria:

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

Secondary Electrical Characteristics (allowable variation):

Breaking Capacity @ Rated Voltage: 35 A or higher
Melting I²t: 21.7 or within application tolerance
DC Cold Resistance: 0.0425 Ohms or within circuit design tolerance

Compliance Criteria:

RoHS3 Compliant (mandatory)
Active product status (mandatory)
Approval agencies must include at least one certification recognized in target market

Substitute parts are grouped into three categories based on electrical performance: Standard Performance (matching 35 A breaking capacity), Enhanced Performance (100 A breaking capacity), and Fast-Acting variants (reduced melting I²t for sensitive circuit protection).

Parameter Comparison

Part Number	Manufacturer	Series	Current (A)	Voltage (V)	Package	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ohms)	Approval Agencies
S506-1.6-R	Eaton	S506	1.6	250	5x20mm	35	21.7	0.0425	BSI, CCC, CSA, CURUS, IMQ, PSE/JET, SEMKO, VDE
BK/S506-1.6-R	Eaton	S506	1.6	250	5x20mm	35	21.7	0.0425	BSI, CCC, CSA, CURUS, IMQ, PSE/JET, SEMKO, VDE
BK/GDC-1.6A	Eaton	GDC	1.6	250	5x20mm	35	21.7	0.0425	cULus, IMQ, MITI/JET
BK/GMD-1.6-R	Eaton	GMD	1.6	250	5x20mm	100	27	0.124	CSA, PSE/JET, UL
GMD-1.6-R	Eaton	GMD	1.6	250	5x20mm	100	27	0.124	CSA, PSE/JET, UL
021801.6MXP	Littelfuse	218	1.6	250	5x20mm	35	23.35	0.0336	CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, VDE
0034.3119	SCHURTER	FST 5x20	1.6	250	5x20mm	35	10.5	—	CCC, cURus, PSE/JET, VDE
0034.3778	SCHURTER	FSL 5x20	1.6	250	5x20mm	100	2.93	—	cULus
0034.5045	SCHURTER	FTT 5x20	1.6	250	5x20mm	35	87	—	cURus
0034.5619.11	SCHURTER	SMD-FST	1.6	250	5x20mm	35	10.5	—	cURus, VDE
021301.6MXP	Littelfuse	213	1.6	250	5x20mm	35	44.2	0.0551	BSI, CCC, CE, CSA, PSE, SEMKO, UR, VDE

Engineering Selection Recommendations

Direct Manufacturer Equivalents (Eaton Electronics Division):

BK/S506-1.6-R is the direct equivalent to S506-1.6-R with identical electrical specifications and approval certifications. This part is suitable for direct substitution without circuit redesign.

BK/GDC-1.6A and GMD-1.6-R series from Eaton provide enhanced breaking capacity (100 A versus 35 A) and higher melting I²t values (27 versus 21.7). These parts are suitable for applications requiring higher fault current withstand capability. Approval certifications differ; GMD series includes UL certification while GDC series includes IMQ and MITI/JET certifications.

Cross-Manufacturer Equivalents (Littelfuse Inc.):

021801.6MXP from Littelfuse series 218 matches the 35 A breaking capacity and provides comparable melting I²t (23.35 versus 21.7). This part includes broader approval coverage including K-MARK and operates across -55°C to 125°C temperature range. DC cold resistance is lower (0.0336 Ohms), which may reduce circuit heating in high-current applications.

021301.6MXP from Littelfuse series 213 provides significantly higher melting I²t (44.2 versus 21.7), suitable for circuits with higher inrush current tolerance. Approval certifications include BSI, CCC, CE, CSA, PSE, SEMKO, UR, and VDE, providing comprehensive regional compliance.

Cross-Manufacturer Equivalents (SCHURTER Inc.):

SCHURTER FST series (0034.3119, 0034.5619.11) provides fast-acting response with reduced melting I²t (10.5 versus 21.7), suitable for sensitive electronic circuits requiring rapid fault isolation. These parts maintain 35 A breaking capacity and include cURus and VDE certifications.

SCHURTER FSL series (0034.3778) provides ultra-fast response (melting I²t 2.93) with enhanced breaking capacity (100 A). This part is suitable for high-speed circuit protection in applications with strict fault clearing requirements. Certification is limited to cULus.

SCHURTER FTT series (0034.5045) provides time-delay response with very high melting I²t (87 versus 21.7), suitable for circuits with sustained inrush currents or motor starting applications. Certification is cURus only.

Selection Criteria by Application:

Standard industrial circuits with moderate fault current: BK/S506-1.6-R, 021801.6MXP
High fault current environments: BK/GMD-1.6-R, GMD-1.6-R, 0034.3778
Sensitive electronic equipment: 0034.3119, 0034.5619.11
Motor or transformer circuits: 0034.5045, 021301.6MXP
Regional compliance requirements: Verify approval agency match to target market

Frequently Asked Questions (FAQ)

Q: Can BK/GMD-1.6-R be used as a direct replacement for S506-1.6-R?

A: BK/GMD-1.6-R is electrically compatible as a substitute. All primary parameters match: 1.6 A current rating, 250 V voltage rating, 5x20mm package, slow-blow response, and cartridge glass fuse type. However, BK/GMD-1.6-R has higher breaking capacity (100 A versus 35 A) and higher melting I²t (27 versus 21.7). This part is suitable for applications where enhanced fault current withstand is beneficial. Approval certifications differ: BK/GMD-1.6-R includes CSA, PSE/JET, and UL, while S506-1.6-R includes BSI, CCC, CSA, CURUS, IMQ, PSE/JET, SEMKO, and VDE. Verify that target market certifications are met.

Q: What is the difference between Littelfuse 021801.6MXP and 021301.6MXP?

A: Both parts are 1.6 A, 250 V, 5x20mm slow-blow glass cartridge fuses from Littelfuse. The primary difference is melting I²t: 021801.6MXP has 23.35 while 021301.6MXP has 44.2. The higher I²t value in 021301.6MXP allows greater inrush current tolerance before fuse operation, making it suitable for circuits with sustained transient currents such as motor starting or transformer inrush. DC cold resistance also differs: 021801.6MXP is 0.0336 Ohms versus 021301.6MXP at 0.0551 Ohms. Approval certifications are similar but 021301.6MXP includes BSI and UR certifications.

Q: Are SCHURTER FST and FSL series interchangeable with S506-1.6-R?

A: SCHURTER FST (0034.3119) and FSL (0034.3778) series are parametrically equivalent in current rating, voltage, and package format. However, they differ significantly in response time characteristics. FST series has melting I²t of 10.5 (fast-acting), while FSL has 2.93 (ultra-fast). S506-1.6-R has melting I²t of 21.7 (slow-blow). These differences affect circuit protection speed. FST and FSL are suitable only for applications where faster fault clearing is required or tolerated. Approval certifications are limited compared to S506-1.6-R. Verify application requirements before substitution.

Q: What does "Breaking Capacity" mean and why does it vary among substitutes?

A: Breaking Capacity is the maximum fault current (in amperes) that the fuse can safely interrupt without rupturing the fuse element or holder. S506-1.6-R has 35 A breaking capacity. Substitute parts with 100 A breaking capacity (BK/GMD-1.6-R, 0034.3778) can safely handle higher fault currents. In circuits with low available fault current, both 35 A and 100 A breaking capacity fuses operate identically. In circuits with high available fault current, only fuses with adequate breaking capacity prevent hazardous rupture. Verify circuit fault current levels before selecting a substitute.

Q: Can I use a substitute fuse with different DC Cold Resistance?

A: DC cold resistance affects circuit heating during normal operation. S506-1.6-R has 0.0425 Ohms. Littelfuse 021801.6MXP has lower resistance (0.0336 Ohms), reducing circuit heating. Littelfuse 021301.6MXP has higher resistance (0.0551 Ohms), increasing circuit heating. SCHURTER parts do not specify DC cold resistance. In low-current circuits, resistance differences are negligible. In high-current circuits near the 1.6 A rating, resistance differences may affect temperature rise. For circuits with tight thermal budgets, verify that substitute fuse resistance is acceptable.

Q: What is the significance of operating temperature range?

A: S506-1.6-R does not specify operating temperature range. Littelfuse 021801.6MXP and 021301.6MXP operate from -55°C to 125°C. SCHURTER 0034.3119 and 0034.5619.11 operate from -55°C to 125°C. SCHURTER 0034.3778 and 0034.5045 operate from -40°C to 85°C. For applications in extreme temperature environments, verify that the substitute fuse operating range covers the installation location temperature extremes.

Q: Are all substitute parts RoHS3 compliant?

A: All substitute parts listed are RoHS3 compliant, matching the compliance status of S506-1.6-R. This ensures compatibility with RoHS3-regulated markets and equipment.

Q: Which substitute provides the closest electrical match to S506-1.6-R?

A: BK/S506-1.6-R is the direct equivalent with identical specifications. Among cross-manufacturer substitutes, Littelfuse 021801.6MXP provides the closest match with 35 A breaking capacity, 23.35 melting I²t (versus 21.7), and comprehensive approval certifications. This part is suitable for direct substitution in most applications.

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