Equivalent & Substitute Parts for BK/GDB-125MA

Part Overview

The BK/GDB-125MA is a 125 mA fast-blow glass cartridge fuse rated for 250 V AC/DC operation in a 5mm x 20mm package form factor. Manufactured by Eaton - Electronics Division under the GDB series, this component requires a fuse holder for installation and is currently in active production status with 1064 units in stock. Alternative equivalent and substitute parts are necessary to support supply chain flexibility, extended lead time mitigation, and design optimization across different application requirements and regional compliance standards.

Substiute Parts

BK/GDB-125MA

Eaton - Electronics DivisionIn Stock: 1097BK/GDB-125MA Datasheet

Current PartRFQ

BK/S500-125-R

Eaton - Electronics DivisionIn Stock: 1200BK/S500-125-R Datasheet

DirectRFQ

BK/GMA-125-R

Eaton - Electronics DivisionIn Stock: 2356BK/GMA-125-R Datasheet

Parametric EquivalentRFQ

BK1/S500-125-R

Eaton - Electronics DivisionIn Stock: 695BK1/S500-125-R Datasheet

Parametric EquivalentRFQ

GMA-125-R

Eaton - Electronics DivisionIn Stock: 1151GMA-125-R Datasheet

Parametric EquivalentRFQ

0034.1507

SCHURTER Inc.In Stock: 10730034.1507 Datasheet

DirectRFQ

0217.125HXP

Littelfuse Inc.In Stock: 11220217.125HXP Datasheet

DirectRFQ

0217.125TXP

Littelfuse Inc.In Stock: 9110217.125TXP Datasheet

DirectRFQ

0235.125HXP

Littelfuse Inc.In Stock: 9740235.125HXP Datasheet

SimilarRFQ

0235.125MXP

Littelfuse Inc.In Stock: 15130235.125MXP Datasheet

Parametric EquivalentRFQ

FSC-125MA

OptiFuseIn Stock: 3366FSC-125MA Datasheet

Parametric EquivalentRFQ

FSD-125MA

OptiFuseIn Stock: 1648FSD-125MA Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the BK/GDB-125MA is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Current Rating: 125 mA (exact match required)
• Voltage Rating (AC): 250 V (exact match required)
• Fuse Type: Cartridge, Glass (exact match required)
• Response Time: Fast Blow (exact match required)
• Package / Case: 5mm x 20mm (exact match required)
• Breaking Capacity @ Rated Voltage: 35A (exact match required)
• Mounting Type: Requires Holder (exact match required)

All substitute parts listed below meet these mandatory parameters. Variations in secondary parameters such as DC Cold Resistance, Melting I²t, approval agencies, and operating temperature ranges do not disqualify substitution but may influence selection based on specific application requirements and regional compliance needs.

Parameter Comparison

Engineering Selection Recommendations

Eaton - Electronics Division Substitutes (Same Manufacturer):

The BK/S500-125-R, BK/GMA-125-R, BK1/S500-125-R, and GMA-125-R are direct Eaton alternatives. BK/S500-125-R and BK1/S500-125-R maintain identical electrical characteristics (Melting I²t: 0.005, DC Cold Resistance: 2.8 Ohms) to the BK/GDB-125MA and are recommended for direct replacement without circuit redesign. BK/GMA-125-R and GMA-125-R feature enhanced approval certifications (CSA, PSE, UL) and ROHS3 compliance, suitable for applications requiring higher regulatory standards. These parts carry higher inventory levels (1143, 2252, and 1060 units respectively), supporting extended availability.

Littelfuse Inc. Substitutes (Multi-Standard Compliance):

The 0217.125HXP and 0217.125TXP from Littelfuse series 217 provide broad international approval coverage (CCC, CE, CSA, K-MARK/KC, SEMKO, UL, VDE) and extended operating temperature range (-55°C ~ 125°C). Melting I²t (0.00478) and DC Cold Resistance (3.82 Ohms) differ from the main part but remain within acceptable substitution parameters. The 0235.125HXP and 0235.125MXP from series 235 offer similar compliance breadth with lower Melting I²t (0.00273) and higher DC Cold Resistance (5.75 Ohms), suitable for applications with tighter thermal constraints. The 0235.125MXP shows the highest inventory availability (1411 units).

SCHURTER Inc. Substitute (Extended Temperature Range):

The 0034.1507 from SCHURTER FSF 5x20 series provides CCC, cURus, and VDE certifications with the widest operating temperature range (-55°C ~ 125°C). Melting I²t (0.00484) aligns closely with Littelfuse alternatives. This part is suitable for industrial applications requiring extended temperature performance.

OptiFuse Substitute (High Breaking Capacity):

The FSC-125MA from OptiFuse series FSC features a significantly higher breaking capacity (100A versus 35A) while maintaining all other electrical parameters. This part carries the highest inventory (3315 units) and cULus/UL 248 certification. Operating temperature range is -55°C ~ 90°C. Selection of this part should be confirmed against circuit breaking capacity requirements.

Frequently Asked Questions (FAQ)

Q: Can I substitute BK/GDB-125MA with any of the listed parts without circuit modification?

A: Yes. All listed substitute parts match the mandatory electrical parameters: 125 mA current rating, 250 V AC voltage rating, fast-blow response, 5x20mm package, and 35A breaking capacity (except FSC-125MA at 100A). Physical installation requires the same fuse holder type. No circuit redesign is necessary for parametric equivalents.

Q: What is the difference between Eaton GDB, GMA, and S500 series fuses?

A: All three series meet the same electrical specifications for this 125 mA application. GMA and S500 variants carry enhanced regulatory certifications (CSA, PSE, UL for GMA; ROHS3 for S500). Series selection depends on regional compliance requirements and design approval documentation.

Q: Why do Littelfuse 217 and 235 series have different Melting I²t values?

A: Melting I²t (0.00478 for 217 series, 0.00273 for 235 series) reflects different thermal response characteristics within the same current and voltage rating. Both remain valid substitutes as they meet the 125 mA fast-blow specification. Application-specific thermal analysis may favor one series over the other.

Q: Is the OptiFuse FSC-125MA suitable as a direct replacement?

A: The FSC-125MA is parametrically equivalent for current, voltage, response time, and package. However, its breaking capacity is 100A versus 35A for the main part. Verify that your circuit design accommodates this higher breaking capacity specification before substitution.

Q: What does ROHS3 compliance mean compared to RoHS Compliant?

A: ROHS3 represents compliance with the latest Restriction of Hazardous Substances directive revision. Both designations indicate absence of restricted materials. ROHS3 is the current standard; parts marked ROHS3 Compliant meet the most recent regulatory requirements.

Q: Which substitute offers the best international approval coverage?

A: The Littelfuse 0217.125HXP and 0217.125TXP carry the broadest certification portfolio: CCC, CE, CSA, K-MARK, SEMKO, UL, and VDE. These parts are suitable for global applications requiring multi-region compliance documentation.

Q: Can I use these substitutes in high-temperature applications?

A: The SCHURTER 0034.1507 and Littelfuse 217/235 series support -55°C ~ 125°C operating range. The OptiFuse FSC-125MA operates to 90°C maximum. The main part BK/GDB-125MA does not specify operating temperature limits. Confirm application temperature requirements against selected substitute specifications.

Q: What inventory levels should I consider for supply chain planning?

A: OptiFuse FSC-125MA offers the highest availability (3315 units), followed by Eaton BK/GMA-125-R (2252 units) and Littelfuse 0235.125MXP (1411 units). For critical applications, these three parts provide the strongest supply position.