5MT 1.6-R Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The 5MT 1.6-R is a 1.6 A 250 V AC/DC glass cartridge fuse manufactured by Bel Fuse Inc., designed for 5mm x 20mm holder applications. This part is classified as obsolete, making equivalent substitutes necessary for ongoing system maintenance and new designs. The fuse features medium blow response characteristics with a 100A breaking capacity at rated voltage, suitable for general-purpose circuit protection in industrial and commercial equipment.

Key Parameters

Parameter	Value
Current Rating	1.6 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Package / Case	5mm x 20mm
Response Time	Medium Blow
Breaking Capacity @ Rated Voltage	100A
Operating Temperature Range	-55°C ~ 125°C
Mounting Type	Requires Holder

Substitute Part Grouping Explanation

Substitution eligibility for the 5MT 1.6-R is determined by strict alignment of the following parameters:

Current Rating: Must be 1.6 A
Voltage Rating (AC): Must be 250 V
Fuse Type: Must be Cartridge, Glass
Package / Case: Must be 5mm x 20mm
Response Time: Medium Blow preferred for direct replacement; Slow Blow variants acceptable only where circuit design permits
Breaking Capacity: 100A minimum for equivalent protection; 35A variants represent reduced protection capability
Mounting Type: Requires Holder (no change)

All substitute parts listed meet the core electrical and mechanical requirements. Variations in melting I²t, DC cold resistance, and approval agencies reflect manufacturer-specific design differences within the same functional class.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Current Rating (A)	Voltage (V AC)	Response Time	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ω)	Product Status
5MT 1.6-R	Bel Fuse Inc.	1.6	250	Medium Blow	100	12	0.081	Obsolete
021801.6MXP	Littelfuse Inc.	1.6	250	Slow Blow	35	23.35	0.0336	Active
023201.6MXP	Littelfuse Inc.	1.6	250	Medium Blow	100	6.96	0.0537	Active
023401.6MXP	Littelfuse Inc.	1.6	250	Medium Blow	100	6.14	0.0884	Active
BK/GMC-1.6-R	Eaton - Electronics Division	1.6	250	Medium Blow	100	5.8	0.067	Active
BK1/GMC-1.6-R	Eaton - Electronics Division	1.6	250	Medium Blow	100	5.8	0.067	Active
GDC-1.6A	Eaton - Electronics Division	1.6	250	Slow Blow	35	21.7	0.0425	Active
GMC-1.6-R	Eaton - Electronics Division	1.6	250	Medium Blow	100	5.8	0.067	Active

Engineering Selection Recommendations

Primary Substitutes (Medium Blow, 100A Breaking Capacity):

The following parts provide direct functional equivalence to the 5MT 1.6-R:

023201.6MXP (Littelfuse Inc., Series 232): Active status, medium blow response, 100A breaking capacity. Certifications: CE, KC, PSE. Melting I²t of 6.96 provides comparable thermal response.
023401.6MXP (Littelfuse Inc., Series 234): Active status, medium blow response, 100A breaking capacity. Certifications: CE, CSA, K-MARK, PSE, UL. Broader approval agency coverage supports international applications.
BK/GMC-1.6-R (Eaton - Electronics Division, Series GMC): Active status, medium blow response, 100A breaking capacity. Certifications: CSA, KC-MARK, MITI, UL. Lowest melting I²t (5.8) indicates fastest thermal response within this group.
BK1/GMC-1.6-R (Eaton - Electronics Division, Series GMC): Active status, medium blow response, 100A breaking capacity. Certifications: CSA, UL. Identical electrical characteristics to BK/GMC-1.6-R with reduced certification scope.
GMC-1.6-R (Eaton - Electronics Division, Series GMC): Active status, medium blow response, 100A breaking capacity. Certifications: CSA, KC-MARK, MITI, UL. Equivalent to BK/GMC-1.6-R variant.

Secondary Substitutes (Slow Blow, 35A Breaking Capacity):

These parts are functionally compatible only in applications where reduced breaking capacity and slower thermal response are acceptable:

021801.6MXP (Littelfuse Inc., Series 218): Active status, slow blow response, 35A breaking capacity. Certifications: CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, VDE. Highest melting I²t (23.35) provides extended thermal tolerance.
GDC-1.6A (Eaton - Electronics Division, Series GDC): Active status, slow blow response, 35A breaking capacity. Certifications: cURus, IMQ, MITI/JET. Melting I²t of 21.7 aligns with slow blow classification.

Compliance Considerations:

All substitute parts maintain ROHS3 compliance and REACH unaffected status. Selection should prioritize parts with certifications matching the original equipment's regional requirements (UL for North America, CE for Europe, PSE for Japan, K-MARK for Korea).

Frequently Asked Questions (FAQ)

Q: Can I use a Slow Blow fuse (021801.6MXP or GDC-1.6A) as a direct replacement for the 5MT 1.6-R?

A: Slow Blow variants are electrically compatible but exhibit different thermal response characteristics. The 5MT 1.6-R is classified as Medium Blow with a melting I²t of 12. Slow Blow substitutes have significantly higher melting I²t values (23.35 for 021801.6MXP, 21.7 for GDC-1.6A), meaning they tolerate higher transient currents before opening. Use only if circuit design analysis confirms that the extended thermal tolerance does not compromise protection objectives. Additionally, Slow Blow variants have reduced breaking capacity (35A vs. 100A), which may be insufficient for high-fault-current applications.

Q: What is the significance of Breaking Capacity differences between 100A and 35A variants?

A: Breaking capacity defines the maximum fault current the fuse can safely interrupt without rupturing or creating an arc hazard. The 5MT 1.6-R has 100A breaking capacity. Substitutes with 35A breaking capacity are suitable only for circuits where the maximum available fault current does not exceed 35A. In higher fault-current environments, 35A-rated fuses may fail catastrophically. Verify the circuit's available fault current before selecting a reduced-capacity substitute.

Q: Are all substitute parts physically interchangeable in a 5mm x 20mm holder?

A: Yes. All listed substitutes conform to the 5mm x 20mm package specification and are mechanically compatible with standard 5x20mm fuse holders. Physical dimensions vary slightly (0.201" to 0.205" diameter), but these variations remain within holder tolerance specifications.

Q: Which substitute offers the best certification coverage for international markets?

A: The 023401.6MXP (Littelfuse Inc., Series 234) carries certifications for CE, CSA, K-MARK, PSE, and UL, providing broad coverage across North American, European, Japanese, and Korean markets. The 021801.6MXP (Littelfuse Inc., Series 218) offers the widest certification set (CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, VDE) and is suitable for applications requiring compliance across multiple regions.

Q: How do melting I²t and DC cold resistance affect fuse performance?

A: Melting I²t determines the thermal energy required to melt the fuse element and is the primary indicator of response speed. Lower I²t values indicate faster response to overcurrent. DC cold resistance affects voltage drop across the fuse during normal operation and influences heat generation. The 5MT 1.6-R has a melting I²t of 12 and DC cold resistance of 0.081 Ω. Substitutes with significantly different I²t values (particularly Slow Blow variants) will exhibit different response times. DC cold resistance variations are typically minor and do not affect circuit protection function in most applications.

Q: Is the obsolete status of the 5MT 1.6-R a concern for long-term supply?

A: Yes. The 5MT 1.6-R is classified as obsolete, indicating Bel Fuse Inc. no longer manufactures this part. All listed substitutes are classified as active and are currently in production. For new designs or long-term system support, select from active substitutes to ensure continued availability. Littelfuse Inc. and Eaton - Electronics Division maintain robust production and distribution networks for their respective product lines.

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