Equivalent & Substitute Parts for BK/GMA-300MA

Part Overview

The BK/GMA-300MA is a 300 mA, 250 V AC/DC fast-blow glass cartridge fuse manufactured by Eaton - Electronics Division in a 5mm x 20mm form factor. This component requires a fuse holder for installation and is designed for circuit protection applications requiring fast response characteristics.

The BK/GMA-300MA carries an obsolete product status. Identifying equivalent and substitute parts ensures design continuity and maintains supply chain reliability for applications currently utilizing this component.

Key Parameters

Parameter	Value
Current Rating	300 mA
Voltage Rating (AC)	250 V
Response Time	Fast Blow
Package / Case	5mm x 20mm
Fuse Type	Cartridge, Glass
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	35A
Melting I²t	0.019

Substitute Part Grouping Explanation

Substitute parts for the BK/GMA-300MA are grouped based on strict electrical and mechanical parameter alignment:

Primary Substitution Criteria:

Current Rating: 300 mA (exact match required)
Voltage Rating: 250 V AC (exact match required)
Response Time: Fast Blow (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Mounting Type: Requires Holder (exact match required)

Eaton GMA Series Direct Equivalents: BK/GMA-300-R, BK1/GMA-300-R, and GMA-300-R are direct manufacturer equivalents from Eaton - Electronics Division. These parts maintain identical electrical specifications and mechanical form factor. The primary distinction is product status: BK/GMA-300-R, BK1/GMA-300-R, and GMA-300-R are active products, whereas BK/GMA-300MA is obsolete.

Littelfuse 235 Series Equivalents: 0235.300HXP, 0235.300MXP, and 0235.300VXP are parametric equivalents manufactured by Littelfuse Inc. These parts satisfy all primary substitution criteria and are active products. Differences exist in melting I²t values and DC cold resistance, which do not affect functional compatibility within the specified electrical parameters.

OptiFuse FSC Series Equivalent: FSC-300MA is a parametric equivalent manufactured by OptiFuse. This part meets all primary substitution criteria and is an active product. The breaking capacity is rated at 100A versus 35A for the main part; however, this represents enhanced capability within the same electrical operating envelope.

Parameter Comparison

Parameter	BK/GMA-300MA	BK/GMA-300-R	BK1/GMA-300-R	GMA-300-R	0235.300HXP	0235.300MXP	0235.300VXP	FSC-300MA
Manufacturer	Eaton	Eaton	Eaton	Eaton	Littelfuse	Littelfuse	Littelfuse	OptiFuse
Current Rating (Amps)	300 mA	300 mA	300 mA	300 mA	300 mA	300 mA	300 mA	300 mA
Voltage Rating - AC	250 V	250 V	250 V	250 V	250 V	250 V	250 V	250 V
Response Time	Fast Blow	Fast Blow	Fast Blow	Fast Blow	Fast Blow	Fast Blow	Fast Blow	Fast Blow
Package / Case	5mm x 20mm	5mm x 20mm	5mm x 20mm	5mm x 20mm	5mm x 20mm	5mm x 20mm	5mm x 20mm	5mm x 20mm
Fuse Type	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass	Cartridge, Glass
Mounting Type	Requires Holder	Requires Holder	Requires Holder	Requires Holder	Requires Holder	Requires Holder	Requires Holder	Requires Holder
Breaking Capacity @ Rated Voltage	35A	35A	35A	35A	35A	35A	35A	100A
Melting I²t	0.019	0.019	0.019	0.019	0.03215	0.03215	0.03215	Not specified
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	RoHS Compliant	RoHS Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Operating Temperature	Not specified	Not specified	Not specified	Not specified	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 125°C	-55°C ~ 90°C

Engineering Selection Recommendations

For Direct Replacement (Eaton GMA Series):

BK/GMA-300-R, BK1/GMA-300-R, and GMA-300-R are recommended as primary substitutes. These parts are manufactured by Eaton - Electronics Division and maintain identical electrical and mechanical specifications to the obsolete BK/GMA-300MA. All three are active products with current manufacturing support. BK/GMA-300-R and GMA-300-R carry ROHS3 compliance, while BK1/GMA-300-R carries RoHS compliance. Selection among these three variants depends on packaging requirements and compliance certifications applicable to the end application.

For Cross-Manufacturer Substitution (Littelfuse 235 Series):

0235.300HXP, 0235.300MXP, and 0235.300VXP are suitable substitutes when cross-manufacturer sourcing is acceptable. These parts satisfy all primary electrical and mechanical parameters. The Littelfuse 235 series carries CE, CSA, KC, and UL certifications. Operating temperature range (-55°C ~ 125°C) exceeds the specification envelope of the main part. All three variants are ROHS3 compliant and REACH unaffected. Selection among these three depends on specific certification requirements for the application.

For Enhanced Breaking Capacity (OptiFuse FSC Series):

FSC-300MA is suitable when enhanced breaking capacity (100A versus 35A) is beneficial within the circuit protection design. This part meets all primary electrical and mechanical parameters and carries cULus and UL 248 certifications. Operating temperature range is -55°C ~ 90°C. ROHS3 compliance is confirmed. This variant is appropriate for applications where higher fault current handling capability provides design margin.

Compliance Considerations:

The BK/GMA-300MA is RoHS non-compliant. All substitute parts listed are RoHS compliant or ROHS3 compliant, supporting transition to modern regulatory requirements. Littelfuse and OptiFuse variants provide expanded operating temperature ranges, which may be advantageous in thermal-constrained applications.

Frequently Asked Questions (FAQ)

Q: Can BK/GMA-300-R be used as a direct replacement for BK/GMA-300MA?

A: Yes. BK/GMA-300-R is a direct manufacturer equivalent from Eaton - Electronics Division. It maintains identical current rating (300 mA), voltage rating (250 V AC), response time (fast blow), package dimensions (5mm x 20mm), and breaking capacity (35A). The primary difference is product status: BK/GMA-300-R is active, while BK/GMA-300MA is obsolete. BK/GMA-300-R is suitable for direct substitution in existing designs.

Q: What is the difference between BK/GMA-300-R, BK1/GMA-300-R, and GMA-300-R?

A: All three are Eaton GMA series equivalents with identical electrical specifications. Differences exist in RoHS compliance status: BK/GMA-300-R and GMA-300-R are ROHS3 compliant, while BK1/GMA-300-R is RoHS compliant. Selection depends on regulatory requirements and certification needs for the end application.

Q: Can Littelfuse 235 series fuses (0235.300HXP, 0235.300MXP, 0235.300VXP) replace the BK/GMA-300MA?

A: Yes. These Littelfuse parts are parametric equivalents meeting all primary electrical and mechanical criteria: 300 mA current rating, 250 V AC voltage rating, fast-blow response, and 5mm x 20mm package. Differences include melting I²t values (0.03215 versus 0.019) and DC cold resistance (1.6 Ohms versus 0.906 Ohms for Eaton parts). These differences do not affect functional compatibility within the specified electrical operating parameters. Littelfuse variants provide expanded operating temperature range (-55°C ~ 125°C) and ROHS3 compliance.

Q: What is the significance of the melting I²t difference between Eaton and Littelfuse parts?

A: Melting I²t is a thermal characteristic indicating the energy required to melt the fuse element. Littelfuse 235 series parts have a higher melting I²t (0.03215) compared to Eaton GMA parts (0.019). This difference reflects different fuse element designs but does not affect compatibility when both parts meet the same current rating, voltage rating, and response time classification. Both designs provide fast-blow protection at 300 mA.

Q: Why does FSC-300MA have a higher breaking capacity (100A) than the main part (35A)?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. FSC-300MA is rated for 100A breaking capacity, while BK/GMA-300MA is rated for 35A. This represents enhanced capability in the OptiFuse design. FSC-300MA remains compatible for direct substitution because it meets all primary electrical parameters (300 mA, 250 V AC, fast-blow, 5mm x 20mm). The higher breaking capacity provides additional design margin in high-fault-current environments.

Q: Are all substitute parts RoHS compliant?

A: Yes. All substitute parts listed are either RoHS compliant or ROHS3 compliant. The main part BK/GMA-300MA is RoHS non-compliant. Substitution with any listed equivalent supports transition to modern environmental and regulatory standards.

Q: Do all substitute parts fit in the same fuse holder as BK/GMA-300MA?

A: Yes. All substitute parts maintain the 5mm x 20mm package dimension and cartridge glass fuse type, requiring the same holder design. Physical compatibility is confirmed across all listed equivalents.

Q: Which substitute part should be selected for applications requiring the widest operating temperature range?

A: Littelfuse 235 series parts (0235.300HXP, 0235.300MXP, 0235.300VXP) provide the widest operating temperature range at -55°C ~ 125°C. Eaton GMA series parts do not specify operating temperature. OptiFuse FSC-300MA specifies -55°C ~ 90°C. Selection depends on the thermal environment of the application.

Q: What certifications are available across the substitute parts?

A: Eaton GMA series parts carry CSA, PSE, and UL certifications. Littelfuse 235 series parts carry CE, CSA, KC, and UL certifications. OptiFuse FSC-300MA carries cULus and UL 248 certifications. Selection should align with certification requirements for the target market and application.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message