GMA-1.25-R Equivalent & Substitute Parts

Part Overview

The GMA-1.25-R is a 1.25 A, 250 V AC/DC fast-blow glass cartridge fuse manufactured by Eaton - Electronics Division. This fuse operates in the 5mm x 20mm form factor and requires a compatible holder for installation. The component is active in production with 1136 pieces in current inventory stock. Equivalent and substitute parts are identified to support procurement flexibility, supply chain continuity, and application-specific compliance requirements across multiple manufacturers and fuse series.

Key Parameters

Parameter	Value
Current Rating	1.25 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Fast Blow
Package / Case	5mm x 20mm
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	100 A
Melting I²t	0.84
RoHS Status	RoHS Compliant

Substitute Part Grouping Explanation

Substitution of the GMA-1.25-R is determined by strict equivalence across the following critical parameters: current rating (1.25 A), voltage rating (250 V AC), fuse type (cartridge glass), response time (fast blow), and physical package (5mm x 20mm). All substitute parts identified maintain these core electrical and mechanical specifications, ensuring functional interchangeability within applications designed for the GMA-1.25-R.

Substitute parts are grouped into two categories:

Direct Manufacturer Equivalents (Eaton - Electronics Division): Parts BK/GMA-1.25-R, BK/S500-1.25-R, BK1/S500-1.25-R, and S500-1.25-R represent alternative part numbers within the Eaton product portfolio. These maintain identical electrical ratings and physical dimensions while differing in series designation, breaking capacity, and compliance certifications.

Cross-Manufacturer Equivalents: Parts from Littelfuse Inc. (02351.25HXP, 02351.25MXP, 02171.25HXP, 02171.25MXP, 02171.25VXP) and SCHURTER Inc. (0034.1517) provide functional equivalence across manufacturers. These parts maintain the same current, voltage, package, and response characteristics while offering different thermal operating ranges, melting I²t values, and approval agency certifications.

Parameter Comparison

Part Number	Manufacturer	Series	Current (A)	Voltage (V AC)	Response Time	Package	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ω)	RoHS Status
GMA-1.25-R	Eaton	GMA	1.25	250	Fast Blow	5x20mm	100	0.84	0.122	RoHS Compliant
BK/GMA-1.25-R	Eaton	GMA	1.25	250	Fast Blow	5x20mm	100	0.84	0.122	ROHS3 Compliant
BK/S500-1.25-R	Eaton	S500	1.25	250	Fast Blow	5x20mm	35	0.84	0.096	RoHS Compliant
BK1/S500-1.25-R	Eaton	S500	1.25	250	Fast Blow	5x20mm	35	0.84	0.096	ROHS3 Compliant
S500-1.25-R	Eaton	S500	1.25	250	Fast Blow	5x20mm	35	0.84	0.096	ROHS3 Compliant
02351.25HXP	Littelfuse	235	1.25	250	Fast Blow	5x20mm	100	1.085	0.1055	ROHS3 Compliant
02351.25MXP	Littelfuse	235	1.25	250	Fast Blow	5x20mm	100	1.085	0.1055	ROHS3 Compliant
0034.1517	SCHURTER	FSF 5x20	1.25	250	Fast Blow	5x20mm	35	1.81	Not Provided	ROHS3 Compliant
02171.25HXP	Littelfuse	217	1.25	250	Fast Blow	5x20mm	35	2.23	0.0701	ROHS3 Compliant
02171.25MXP	Littelfuse	217	1.25	250	Fast Blow	5x20mm	35	2.23	0.0701	ROHS3 Compliant
02171.25VXP	Littelfuse	217	1.25	250	Fast Blow	5x20mm	35	2.23	0.0701	ROHS3 Compliant

Engineering Selection Recommendations

Eaton GMA Series (GMA-1.25-R, BK/GMA-1.25-R): These parts provide the highest breaking capacity at 100 A and are suitable for applications requiring maximum fault current protection. The GMA-1.25-R carries CSA, PSE, and UL certifications. The BK/GMA-1.25-R variant offers ROHS3 compliance and is recommended where enhanced environmental compliance is specified.

Eaton S500 Series (BK/S500-1.25-R, BK1/S500-1.25-R, S500-1.25-R): These parts operate at a reduced breaking capacity of 35 A and are suitable for lower fault current applications. The S500 series carries broader international certifications including BSI, CCC, CSA, cULus, IMQ, SEMKO, and VDE. The BK1/S500-1.25-R and S500-1.25-R variants provide ROHS3 compliance.

Littelfuse 235 Series (02351.25HXP, 02351.25MXP): These parts match the GMA-1.25-R breaking capacity at 100 A and provide operating temperature range of -55°C to 125°C. Certifications include CE, CSA, KC, PSE, and UL. These parts are suitable for applications requiring extended thermal operating range.

Littelfuse 217 Series (02171.25HXP, 02171.25MXP, 02171.25VXP): These parts operate at 35 A breaking capacity with the highest melting I²t value of 2.23 and lowest DC cold resistance of 0.0701 Ω. Operating temperature range is -55°C to 125°C. Certifications include BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, and VDE. These parts are suitable for applications requiring extended thermal range and broad international compliance.

SCHURTER FSF 5x20 Series (0034.1517): This part operates at 35 A breaking capacity with melting I²t of 1.81 and operating temperature range of -55°C to 125°C. Certifications include CCC, cURus, PSE/JET, and VDE. This part is suitable for applications requiring specific SCHURTER product qualification.

Selection should be based on application breaking capacity requirements, thermal operating environment, and required compliance certifications. All identified parts maintain electrical and mechanical compatibility with the GMA-1.25-R within their specified operating parameters.

Frequently Asked Questions (FAQ)

Q: Can the GMA-1.25-R be directly replaced with any of the listed substitute parts?

A: All listed substitute parts maintain the same current rating (1.25 A), voltage rating (250 V AC), fuse type (cartridge glass), response time (fast blow), and physical package (5mm x 20mm). Direct mechanical and electrical substitution is supported. However, breaking capacity differs between series: GMA and Littelfuse 235 series operate at 100 A, while S500, Littelfuse 217, and SCHURTER FSF series operate at 35 A. Application circuit design must accommodate the breaking capacity of the selected substitute.

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

A: Both series maintain identical electrical ratings and physical dimensions. The primary difference is breaking capacity: GMA-1.25-R provides 100 A breaking capacity, while S500 variants provide 35 A breaking capacity. The S500 series carries a broader range of international certifications (BSI, CCC, CSA, cULus, IMQ, SEMKO, VDE) compared to the GMA series (CSA, PSE, UL).

Q: Why do Littelfuse 217 series parts have lower DC cold resistance than other substitutes?

A: DC cold resistance is a measured electrical characteristic that varies by manufacturer design and construction. The Littelfuse 217 series (0.0701 Ω) exhibits lower resistance than the GMA-1.25-R (0.122 Ω) and other series. This difference does not affect functional substitution but may influence circuit behavior in applications sensitive to fuse resistance characteristics.

Q: What is the significance of melting I²t values in the parameter comparison?

A: Melting I²t represents the thermal energy required to melt the fuse element and is a characteristic of fuse design. The GMA-1.25-R has a melting I²t of 0.84, while Littelfuse 217 series parts have 2.23 and SCHURTER 0034.1517 has 1.81. These differences reflect different fuse element designs and thermal response characteristics. All parts maintain the same fast-blow response classification and are functionally equivalent for the specified 1.25 A current rating.

Q: Are all substitute parts RoHS compliant?

A: All identified substitute parts carry either RoHS Compliant or ROHS3 Compliant status. ROHS3 represents compliance with the most recent RoHS directive revision. The original GMA-1.25-R is RoHS Compliant. Selection between RoHS Compliant and ROHS3 Compliant variants should be based on application and procurement requirements.

Q: What certifications should I consider when selecting a substitute?

A: Certification selection depends on the geographic market and application requirements. The GMA-1.25-R carries CSA, PSE, and UL certifications. Eaton S500 series parts carry BSI, CCC, CSA, cULus, IMQ, SEMKO, and VDE certifications. Littelfuse 235 series carries CE, CSA, KC, PSE, and UL certifications. Littelfuse 217 series carries BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, and VDE certifications. SCHURTER 0034.1517 carries CCC, cURus, PSE/JET, and VDE certifications. Select based on required market compliance.

Q: Can I use a substitute part with a different breaking capacity in my application?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. The GMA-1.25-R and Littelfuse 235 series provide 100 A breaking capacity, while S500, Littelfuse 217, and SCHURTER FSF series provide 35 A breaking capacity. Substitution with a lower breaking capacity part is only acceptable if the application circuit fault current does not exceed 35 A. Substitution with a higher breaking capacity part is always acceptable from a breaking capacity perspective.

Q: What is the operating temperature range for each substitute part?

A: The GMA-1.25-R does not specify an operating temperature range. Littelfuse 235 series (02351.25HXP, 02351.25MXP) operates from -55°C to 125°C. Littelfuse 217 series (02171.25HXP, 02171.25MXP, 02171.25VXP) operates from -55°C to 125°C. SCHURTER 0034.1517 operates from -55°C to 125°C. Eaton S500 series does not specify an operating temperature range. For applications requiring extended thermal operating range, Littelfuse or SCHURTER substitutes are recommended.

Q: Are there inventory considerations when selecting a substitute?

A: Current inventory levels are: GMA-1.25-R (1136 pcs), BK/GMA-1.25-R (1110 pcs), BK/S500-1.25-R (832 pcs), BK1/S500-1.25-R (2212 pcs), S500-1.25-R (835 pcs), 02351.25HXP (1372 pcs), 02351.25MXP (2630 pcs), 0034.1517 (1951 pcs), 02171.25HXP (1500 pcs), 02171.25MXP (5025 pcs), and 02171.25VXP (831 pcs). Inventory levels should be verified at time of procurement as stock quantities change.

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