GMC-250-R Equivalent & Substitute Parts

Part Overview

The GMC-250-R is a 250 mA, 250 V AC/DC glass cartridge fuse manufactured by Eaton - Electronics Division. This fuse operates with medium blow response time and requires a holder for installation. The 5mm x 20mm form factor is a standard package size for low-current circuit protection applications. The part is active in production and carries multiple international approvals including CSA, KC-MARK, and UL certifications. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity.

Key Parameters

Parameter	Value
Current Rating	250 mA
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Package / Case	5mm x 20mm
Response Time	Medium Blow
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	35A
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the GMC-250-R are classified into two categories based on electrical and mechanical compatibility:

Direct Manufacturer Equivalents (Eaton - Electronics Division): Parts BK/GMC-250-R and BK1/GMC-250-R are direct equivalents manufactured by Eaton. These parts share identical electrical specifications including 250 mA current rating, 250 V AC voltage rating, medium blow response time, 5mm x 20mm package dimensions, and 35A breaking capacity. All three Eaton variants carry CSA, KC-MARK, and UL approvals and are ROHS3 compliant.

Cross-Manufacturer Parametric Equivalents: Parts 0218.250HXP, 0218.250TXP (Littelfuse Inc.), 20102500021P (Littelfuse Inc.), and MSC-250MA (OptiFuse) are parametric equivalents that match the core electrical and mechanical specifications of the GMC-250-R. These parts maintain the same 250 mA current rating, 250 V AC voltage rating, 5mm x 20mm package dimensions, and 35A breaking capacity. However, these cross-manufacturer substitutes exhibit variations in response time characteristics, melting I²t values, DC cold resistance, operating temperature ranges, and approval agency certifications.

Substitution eligibility is determined by matching the following critical parameters:

Current Rating: 250 mA
Voltage Rating (AC): 250 V
Package / Case: 5mm x 20mm
Fuse Type: Cartridge, Glass
Mounting Type: Requires Holder

Parameter Comparison

Part Number	Manufacturer	Current Rating (mA)	Voltage Rating (V AC)	Response Time	Package	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ohms)	RoHS Status	Product Status
GMC-250-R	Eaton	250	250	Medium Blow	5x20mm	35	0.046	0.965	ROHS3	Active
BK/GMC-250-R	Eaton	250	250	Medium Blow	5x20mm	35	0.046	0.965	ROHS3	Active
BK1/GMC-250-R	Eaton	250	250	Medium Blow	5x20mm	35	0.046	0.965	ROHS3	Active
0218.250HXP	Littelfuse	250	250	Slow Blow	5x20mm	35	0.5405	1.0495	ROHS3	Active
0218.250TXP	Littelfuse	250	250	Slow Blow	5x20mm	35	0.5405	1.0495	ROHS3	Active
20102500021P	Littelfuse	250	250	Medium Blow	5x20mm	80	0.13	Not Provided	ROHS3	Active
MSC-250MA	OptiFuse	250	250	Medium Blow	5x20mm	100	0.1341	Not Provided	ROHS3	Active

Engineering Selection Recommendations

Eaton Direct Equivalents (BK/GMC-250-R, BK1/GMC-250-R): These parts are direct substitutes for the GMC-250-R with identical electrical and thermal characteristics. All three variants are manufactured by Eaton - Electronics Division, carry the same approvals (CSA, KC-MARK, UL), and maintain ROHS3 compliance. Selection among GMC-250-R, BK/GMC-250-R, and BK1/GMC-250-R is based on inventory availability and procurement requirements without electrical performance differentiation.

Littelfuse 0218.250HXP and 0218.250TXP: These parts are parametric equivalents with identical current, voltage, and package specifications. However, both exhibit slow blow response time characteristics compared to the medium blow response of the GMC-250-R. The melting I²t value is significantly higher (0.5405 versus 0.046), indicating delayed response to overcurrent conditions. These parts carry broader international approvals (CCC, CE, CSA, K-MARK, SEMKO, UL, VDE) and operate across an extended temperature range (-55°C to 125°C). Selection of these parts requires confirmation that slow blow response time is acceptable for the application.

Littelfuse 20102500021P: This part maintains medium blow response time and is approved by cULus. The breaking capacity is elevated to 80A compared to 35A for the GMC-250-R. Operating temperature range is -25°C to 70°C. This part is suitable for applications requiring medium blow response with higher fault current handling capability.

OptiFuse MSC-250MA: This part maintains medium blow response time with the highest breaking capacity at 100A. Operating temperature range is -55°C to 125°C, matching the extended range of Littelfuse slow blow variants. This part is approved by cULus and UL 248. Selection is appropriate for applications requiring medium blow response with maximum fault current capacity.

All substitute parts are active in production and ROHS3 compliant. Selection should be based on response time requirements, breaking capacity specifications, operating temperature range, and approval agency certifications applicable to the end application.

Frequently Asked Questions (FAQ)

Q: Can BK/GMC-250-R and BK1/GMC-250-R be used interchangeably with GMC-250-R?

A: Yes. BK/GMC-250-R and BK1/GMC-250-R are direct equivalents manufactured by Eaton with identical electrical specifications, response time, breaking capacity, and approvals. These parts are electrically and mechanically interchangeable with the GMC-250-R.

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

A: Response time classification indicates the fuse element's thermal response to overcurrent conditions. Medium blow fuses respond faster to sustained overcurrent than slow blow fuses. The GMC-250-R has medium blow response time (melting I²t of 0.046). Littelfuse 0218.250HXP and 0218.250TXP have slow blow response time (melting I²t of 0.5405), meaning they tolerate higher inrush currents before opening. Application requirements determine which response time is appropriate.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed—BK/GMC-250-R, BK1/GMC-250-R, 0218.250HXP, 0218.250TXP, 20102500021P, and MSC-250MA—are ROHS3 compliant.

Q: What does breaking capacity mean, and why does it vary among substitutes?

A: Breaking capacity is the maximum fault current the fuse can safely interrupt at rated voltage without rupturing or creating a hazard. The GMC-250-R has a breaking capacity of 35A. Littelfuse 20102500021P has 80A, and OptiFuse MSC-250MA has 100A. Higher breaking capacity provides greater protection margin in high-fault-current environments. Application circuit design determines the required breaking capacity.

Q: Can I substitute a slow blow fuse for a medium blow fuse?

A: Substitution of slow blow for medium blow requires application-level analysis. Slow blow fuses tolerate higher inrush currents and respond more slowly to overcurrent. If the application circuit is designed for medium blow response characteristics, substituting a slow blow fuse may result in inadequate protection during fault conditions. Conversely, if the application experiences acceptable inrush currents and requires delayed response, slow blow substitution is permissible.

Q: Do all substitute parts fit the same holder as the GMC-250-R?

A: Yes. All substitute parts maintain the 5mm x 20mm package dimensions and require a holder for installation, identical to the GMC-250-R. Physical installation compatibility is confirmed across all listed substitutes.

Q: What approval agencies certify these fuses?

A: The GMC-250-R carries CSA, KC-MARK, and UL approvals. Eaton equivalents (BK/GMC-250-R, BK1/GMC-250-R) carry the same approvals. Littelfuse parts carry broader certifications including CCC, CE, CSA, K-MARK, SEMKO, UL, and VDE. OptiFuse MSC-250MA carries cULus and UL 248 approvals. Application requirements and regional standards determine which certifications are necessary.

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

A: The GMC-250-R does not specify an operating temperature range. Littelfuse 0218.250HXP and 0218.250TXP operate from -55°C to 125°C. Littelfuse 20102500021P operates from -25°C to 70°C. OptiFuse MSC-250MA operates from -55°C to 125°C. Application environment determines whether extended temperature range is required.

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