Equivalent & Substitute Parts for 5MT 4-R Fuse Cartridge

Part Overview

The Bel Fuse Inc. 5MT 4-R is a 4A 125VAC glass cartridge fuse in 5mm x 20mm form factor, designed for circuits requiring medium-blow response characteristics. This part is classified as obsolete, necessitating identification of active equivalent and substitute components from current manufacturers. Substitute parts must maintain electrical compatibility within the specified voltage and current ratings while accommodating mechanical and performance variations inherent to different fuse technologies and manufacturers.

Key Parameters

Parameter	Value
Current Rating	4 A
Voltage Rating (AC)	125 V
Package / Case	5mm x 20mm
Fuse Type	Cartridge, Glass
Response Time	Medium Blow
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	10kA
Operating Temperature Range	-55°C ~ 125°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following criteria:

Primary Compatibility Requirements:

Current Rating: 4 A (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Mounting Type: Requires Holder (exact match required)
Voltage Rating (AC): 125 V minimum (equal or higher acceptable)
RoHS Status: ROHS3 Compliant (required)

Secondary Variation Parameters:

Fuse Type: Glass or Ceramic cartridge acceptable
Response Time: Medium Blow or Slow Blow acceptable
Breaking Capacity: Variation permitted within rated voltage
Melting I²t: Variation permitted based on response time classification
DC Cold Resistance: Variation permitted within operational limits

Substitute parts are grouped into two categories: direct equivalents maintaining identical electrical characteristics, and functional substitutes accommodating technology or response time variations while preserving circuit protection function.

Parameter Comparison

Parameter	5MT 4-R (Bel Fuse)	0233004.MXP (Littelfuse)	0239004.HXP (Littelfuse)	0234004.MXP (Littelfuse)	BK1/GMC-4-R (Eaton)
Manufacturer	Bel Fuse Inc.	Littelfuse Inc.	Littelfuse Inc.	Littelfuse Inc.	Eaton - Electronics Division
Current Rating (Amps)	4 A	4 A	4 A	4 A	4 A
Voltage Rating - AC	125 V	125 V	125 V	250 V	125 V
Fuse Type	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Ceramic	Cartridge, Glass
Response Time	Medium Blow	Medium Blow	Slow Blow	Medium Blow	Medium Blow
Package / Case	5mm x 20mm	5mm x 20mm	5mm x 20mm	5mm x 20mm	5mm x 20mm
Breaking Capacity @ Rated Voltage	10kA	10kA	10kA	200A	10kA
Melting I²t	99	51.61	270.703	10.37	36
DC Cold Resistance (Ohms)	0.022	0.0293	0.0312	0.0304	0.019
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	Not specified
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	CE, CSA, cURus, PSE	CE, CSA, KC, PSE, UL	CE, CSA, KC, PSE, UL	CE, CSA, K-MARK, PSE, UL	CSA, KC, MITI, UL

Engineering Selection Recommendations

Direct Equivalents (Preferred for 125V AC Circuits):

The Littelfuse 0233004.MXP and Eaton BK1/GMC-4-R are direct functional equivalents to the 5MT 4-R. Both maintain 4A current rating, 125V AC voltage rating, medium-blow response time, and 5mm x 20mm package dimensions. All three parts carry ROHS3 compliance and equivalent thermal operating ranges. The 0233004.MXP offers the broadest regulatory approval coverage (CE, CSA, KC, PSE, UL) and highest current inventory availability (5100 pcs). The BK1/GMC-4-R provides equivalent performance with CSA, KC, MITI, and UL certifications.

Slow-Blow Alternative (For Inrush Current Applications):

The Littelfuse 0239004.HXP maintains identical voltage, current, and package specifications but provides slow-blow response characteristics (Melting I²t: 270.703 versus 99 for the original). This substitute is appropriate for circuits experiencing transient inrush currents or requiring extended response time before fuse operation. Regulatory approvals include CE, CSA, KC, PSE, and UL.

Higher Voltage Rated Alternative (For Dual-Voltage Circuits):

The Littelfuse 0234004.MXP is rated for 250V AC operation while maintaining 4A current rating and 5mm x 20mm package form factor. This ceramic cartridge fuse is suitable for circuits designed to operate across 125V and 250V supply ranges. The ceramic construction provides lower melting I²t (10.37) and higher breaking capacity (200A) compared to glass alternatives. This part carries CE, CSA, K-MARK, PSE, and UL approvals.

Selection Criteria:

For direct replacement in 125V AC circuits: Select 0233004.MXP or BK1/GMC-4-R
For circuits with inrush current requirements: Select 0239004.HXP
For dual-voltage or 250V AC circuits: Select 0234004.MXP
All substitutes maintain ROHS3 compliance and equivalent thermal operating specifications

Frequently Asked Questions (FAQ)

Q: Can the 0234004.MXP (250V rated) be used in a 125V AC circuit?

A: Yes. The 0234004.MXP is rated for 250V AC operation and is therefore suitable for 125V AC circuits. Higher voltage ratings provide additional safety margin. However, the ceramic construction and lower melting I²t (10.37) differ from the original glass cartridge design. Verify circuit protection requirements before substitution.

Q: What is the difference between medium-blow and slow-blow response times?

A: Medium-blow fuses (5MT 4-R, 0233004.MXP, BK1/GMC-4-R) operate with standard response characteristics suitable for general-purpose circuits. Slow-blow fuses (0239004.HXP) tolerate brief overcurrent transients before operation, appropriate for circuits with inrush currents or motor startup conditions. Melting I²t values quantify this difference: higher values indicate slower response.

Q: Are all substitute parts mechanically compatible with the original fuse holder?

A: Yes. All substitute parts maintain the 5mm x 20mm cartridge package dimension and require holder mounting. Physical installation is identical. Verify holder specifications match the 5mm x 20mm standard before installation.

Q: Which substitute offers the best regulatory coverage?

A: The Littelfuse 0233004.MXP carries the broadest approval agency certifications (CE, CSA, KC, PSE, UL) and maintains direct electrical equivalence to the 5MT 4-R. This part is recommended for applications requiring comprehensive regulatory compliance documentation.

Q: Can glass and ceramic cartridge fuses be interchanged?

A: Glass and ceramic cartridges differ in construction, breaking capacity, and melting characteristics. The 0234004.MXP ceramic fuse provides 200A breaking capacity versus 10kA for glass alternatives. Substitution is permitted only when circuit protection requirements accommodate these performance variations. Consult circuit design specifications before interchanging fuse types.

Q: What inventory status should influence substitution decisions?

A: All substitute parts are classified as active products with substantial inventory availability (0233004.MXP: 5100 pcs, 0239004.HXP: 6788 pcs, 0234004.MXP: 4345 pcs, BK1/GMC-4-R: 662 pcs). The original 5MT 4-R is obsolete with no new production. Active substitutes ensure long-term supply chain continuity.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message