Littelfuse 021806.3MXBP Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 021806.3MXBP is a 6.3 A, 250 V AC/DC slow-blow glass cartridge fuse in 5mm x 20mm form factor. This fuse is designed for circuit protection in applications requiring slow-blow response characteristics and is actively manufactured. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, and performance characteristics to ensure direct functional replacement in holder-based fuse applications.

Key Parameters

Parameter	Value
Current Rating	6.3 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Slow Blow
Package / Case	5mm x 20mm
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	63 A
Operating Temperature Range	-55°C to 125°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following criteria:

Primary Matching Parameters (Required for Direct Substitution):

Current Rating: 6.3 A
Voltage Rating (AC): 250 V
Fuse Type: Cartridge, Glass
Response Time: Slow Blow
Package / Case: 5mm x 20mm
Mounting Type: Requires Holder

Secondary Considerations:

Breaking Capacity @ Rated Voltage
Melting I²t value
DC Cold Resistance
Approval Agency certifications
Series designation

Substitute parts are grouped into two categories:

Category 1: Littelfuse Series 218 Variants — Parts 021806.3HXP, 021806.3MXF34P, 021806.3MXP, and 021806.3TXP share identical electrical and mechanical specifications with the main part, including matching Breaking Capacity (63 A) and Melting I²t (198.5). These differ only in packaging designation or approval agency combinations.

Category 2: Littelfuse Series 219XA High-Breaking-Capacity Variants — Parts 021906.3MXABP and 021906.3MXAP maintain all primary matching parameters but feature enhanced Breaking Capacity (150 A) and higher Melting I²t (1093.035). These are suitable for applications requiring higher fault current withstand capability.

Category 3: Littelfuse Series 618 Variant — Part 061806.3MXP matches all primary parameters with identical Breaking Capacity and Melting I²t but carries a different approval agency set (CCC, CE, CSA, UR, VDE).

Category 4: SCHURTER Direct Equivalents — Parts 0034.3125 and 0034.5625.11 from SCHURTER Inc. meet all primary matching parameters with comparable Breaking Capacity (63 A) and Melting I²t (190), offering cross-manufacturer substitution options.

Parameter Comparison

Part Number	Manufacturer	Series	Current (A)	Voltage (V AC)	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ω)	Inventory (Pcs)
021806.3MXBP	Littelfuse	218	6.3	250	63	198.5	0.0076	1768
021306.3MXP	Littelfuse	213	6.3	250	63	600	0.0095	1719
021806.3HXP	Littelfuse	218	6.3	250	63	198.5	0.0076	1600
021806.3MXF34P	Littelfuse	218	6.3	250	63	198.5	0.0076	1499
021806.3MXP	Littelfuse	218	6.3	250	63	198.5	0.0076	2743
021806.3TXP	Littelfuse	218	6.3	250	63	198.5	0.0076	990
021906.3MXABP	Littelfuse	219XA	6.3	250	150	1093.035	0.0117	1551
021906.3MXAP	Littelfuse	219XA	6.3	250	150	1093.035	0.0117	1561
061806.3MXP	Littelfuse	618	6.3	250	63	198.5	0.0076	1753
0034.3125	SCHURTER	FST 5x20	6.3	250	63	190	—	59595
0034.5625.11	SCHURTER	SMD-FST	6.3	250	63	190	—	1692

Engineering Selection Recommendations

For Direct Replacement with Identical Performance: Select from Littelfuse Series 218 variants (021806.3HXP, 021806.3MXF34P, 021806.3MXP, 021806.3TXP). These parts maintain identical Breaking Capacity (63 A) and Melting I²t (198.5), ensuring equivalent protection characteristics. Part 021806.3MXP offers the highest inventory availability (2743 pcs).

For Enhanced Fault Current Withstand: Littelfuse Series 219XA variants (021906.3MXABP, 021906.3MXAP) provide increased Breaking Capacity (150 A) and higher Melting I²t (1093.035) while maintaining all primary electrical and mechanical parameters. These are suitable for applications with higher available fault currents.

For Cross-Manufacturer Substitution: SCHURTER 0034.3125 (FST 5x20 series) provides equivalent performance with comparable Breaking Capacity (63 A) and Melting I²t (190). This part carries the highest inventory level (59595 pcs) and is certified to CCC, cURus, PSE/JET, and VDE standards.

Certification Alignment: The main part 021806.3MXBP carries CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, and VDE approvals. All Littelfuse substitutes maintain CE, CSA, CCC, PSE, SEMKO, and VDE certifications. Verify specific approval requirements for your application before selection.

Frequently Asked Questions (FAQ)

Q: Can I use a Series 219XA part (021906.3MXABP) as a direct replacement for the 021806.3MXBP?

A: Yes. The Series 219XA variants match all primary electrical and mechanical parameters (6.3 A, 250 V AC, 5mm x 20mm, slow-blow response). The higher Breaking Capacity (150 A vs. 63 A) and Melting I²t (1093.035 vs. 198.5) represent enhanced performance characteristics suitable for higher fault current environments. No circuit modification is required.

Q: What is the difference between Littelfuse Series 218 and Series 213 variants?

A: Both series maintain identical current rating (6.3 A), voltage (250 V AC), and package dimensions (5mm x 20mm). The primary difference is Melting I²t: Series 213 (021306.3MXP) has 600 compared to Series 218's 198.5. This affects thermal response characteristics. Series 213 also includes BSI certification not present in Series 218.

Q: Are SCHURTER 0034.3125 and Littelfuse 021806.3MXBP fully interchangeable?

A: Yes. Both parts share identical current rating (6.3 A), voltage (250 V AC), package dimensions (5mm x 20mm), and response time (slow-blow). Breaking Capacity and Melting I²t are comparable (63 A and 190 vs. 198.5). Certification coverage differs slightly; verify that SCHURTER's CCC, cURus, PSE/JET, and VDE approvals meet your application requirements.

Q: What does "Requires Holder" mean for mounting type?

A: All listed parts are cartridge fuses designed for use in dedicated fuse holders. They are not surface-mount or panel-mount components. Ensure your application uses a compatible 5mm x 20mm fuse holder rated for 250 V AC and 6.3 A minimum.

Q: Can I substitute a 6.3 A fuse with a higher current rating fuse?

A: No. Fuse current rating must match the circuit design specification. Using a higher-rated fuse (e.g., 10 A instead of 6.3 A) eliminates circuit protection and creates fire and equipment damage risk.

Q: What is the significance of DC Cold Resistance values?

A: DC Cold Resistance (measured in ohms) affects voltage drop across the fuse during normal operation. Lower values (0.0076 Ω for Series 218) result in minimal voltage drop. Series 219XA parts show slightly higher resistance (0.0117 Ω) due to internal construction differences. This difference is negligible in most applications but may be relevant in low-voltage, high-current circuits.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message