BK/GMC-500MA Equivalent & Substitute Parts

Part Overview

The BK/GMC-500MA is a 500 mA, 250 V AC/DC glass cartridge fuse with a 5mm x 20mm form factor manufactured by Eaton - Electronics Division. This component is classified as obsolete and requires a holder for installation. Due to its obsolete product status, direct equivalents and parametric substitutes are available from active product lines within the same and alternative manufacturers. Substitution is necessary to ensure continued availability and access to components with equivalent electrical and mechanical specifications.

Key Parameters

Parameter	Value
Current Rating	500 mA
Voltage Rating - AC	250 V
Fuse Type	Cartridge, Glass
Package / Case	5mm x 20mm
Response Time	Medium Blow
Breaking Capacity @ Rated Voltage	35A
Mounting Type	Requires Holder
Size / Dimension	0.205" Dia x 0.787" L (5.20mm x 20.00mm)

Substitute Part Grouping Explanation

Substitution of the BK/GMC-500MA is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Current Rating: 500 mA (exact match required)
Voltage Rating - AC: 250 V (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)

Secondary Compatibility Parameters:

Response Time: Medium Blow (preferred for direct equivalence)
Breaking Capacity @ Rated Voltage: 35A or higher (acceptable)
DC Cold Resistance: 0.335 Ohms nominal (acceptable within tolerance)
Melting I²t: 0.41 nominal (acceptable within tolerance)

Substitute parts are grouped into two categories:

Direct Manufacturer Equivalents (Eaton - Electronics Division): Parts BK/GMC-500-R, BK1/GMC-500-R, and GMC-500-R maintain identical electrical and mechanical specifications with active product status and improved RoHS compliance.

Parametric Equivalents (Alternative Manufacturers): Parts from Littelfuse Inc. (0218.500MXP, 0218.500TXP, 20105000001, 20105000001P, 20105000021, 20105000021P) and SCHURTER Inc. (0034.2513) meet all primary substitution criteria. Variations in response time, melting I²t, breaking capacity, and operating temperature ranges are noted but do not preclude substitution when primary parameters align.

Parameter Comparison

Part Number	Manufacturer	Current Rating (mA)	Voltage AC (V)	Package	Response Time	Breaking Capacity (A)	Melting I²t	Product Status	RoHS Status
BK/GMC-500MA	Eaton	500	250	5x20mm	Medium Blow	35	0.41	Obsolete	Non-compliant
BK/GMC-500-R	Eaton	500	250	5x20mm	Medium Blow	35	0.41	Active	ROHS3 Compliant
BK1/GMC-500-R	Eaton	500	250	5x20mm	Medium Blow	35	0.41	Active	ROHS3 Compliant
GMC-500-R	Eaton	500	250	5x20mm	Medium Blow	35	0.41	Active	ROHS3 Compliant
0218.500MXP	Littelfuse	500	250	5x20mm	Slow Blow	35	2.825	Active	ROHS3 Compliant
0218.500TXP	Littelfuse	500	250	5x20mm	Slow Blow	35	2.825	Active	ROHS3 Compliant
20105000001	Littelfuse	500	250	5x20mm	Medium Blow	80	0.35	Active	ROHS3 Compliant
20105000001P	Littelfuse	500	250	5x20mm	Medium Blow	80	0.35	Active	ROHS3 Compliant
20105000021	Littelfuse	500	250	5x20mm	Medium Blow	80	0.35	Active	ROHS3 Compliant
20105000021P	Littelfuse	500	250	5x20mm	Medium Blow	80	0.35	Active	ROHS3 Compliant
0034.2513	SCHURTER	500	250	5x20mm	Medium Blow	80	0.675	Active	ROHS3 Compliant

Engineering Selection Recommendations

Tier 1 - Direct Equivalents (Recommended Primary Selection):

The Eaton - Electronics Division parts BK/GMC-500-R, BK1/GMC-500-R, and GMC-500-R are direct functional equivalents to the BK/GMC-500MA. These parts maintain identical electrical characteristics (500 mA, 250 V AC, 35A breaking capacity, 0.41 melting I²t, medium blow response) and mechanical form factor (5mm x 20mm). All three are active products with ROHS3 compliance, providing superior regulatory alignment compared to the obsolete original part. Selection among these three variants depends on packaging requirements and inventory availability.

Tier 2 - Parametric Equivalents with Medium Blow Response (Secondary Selection):

The Littelfuse 201 series parts (20105000001, 20105000001P, 20105000021, 20105000021P) and SCHURTER 0034.2513 maintain medium blow response time matching the original BK/GMC-500MA. These parts meet all primary substitution criteria (500 mA, 250 V AC, 5mm x 20mm package). Differences include higher breaking capacity (80A versus 35A) and lower melting I²t values (0.35 to 0.675 versus 0.41). These parts are active products with ROHS3 compliance and cULus or equivalent certifications.

Tier 3 - Parametric Equivalents with Slow Blow Response (Tertiary Selection):

The Littelfuse 218 series parts (0218.500MXP, 0218.500TXP) meet all primary substitution criteria but feature slow blow response time and elevated melting I²t (2.825 versus 0.41). These parts are active products with comprehensive international certifications (CCC, CE, CSA, K-MARK, SEMKO, UL, VDE) and extended operating temperature range (-55°C to 125°C). Selection of slow blow variants is appropriate only when circuit design specifically requires delayed response characteristics.

Compliance Considerations:

All recommended substitute parts carry ROHS3 compliance, addressing regulatory requirements superior to the non-compliant original part. Approval agencies vary across manufacturers; Eaton parts carry CSA, KC-MARK, and UL certifications; Littelfuse parts carry cULus or expanded international certifications; SCHURTER parts carry no listed approval agencies in provided data.

Frequently Asked Questions (FAQ)

Q: Can BK/GMC-500MA be directly replaced with BK/GMC-500-R?

A: Yes. BK/GMC-500-R is a direct equivalent manufactured by the same company (Eaton - Electronics Division) with identical electrical and mechanical specifications. The primary difference is active product status and ROHS3 compliance versus the obsolete, non-compliant original part.

Q: What is the difference between medium blow and slow blow fuses in the substitute list?

A: Response time characterizes how quickly a fuse opens under overcurrent conditions. Medium blow fuses (BK/GMC-500MA, BK/GMC-500-R, BK1/GMC-500-R, GMC-500-R, 20105000001 series, 0034.2513) open at standard rates. Slow blow fuses (0218.500MXP, 0218.500TXP) tolerate temporary overcurrent surges before opening. Selection depends on circuit requirements; medium blow is appropriate for general protection, slow blow for circuits with inrush current.

Q: Are Littelfuse and SCHURTER parts compatible with existing BK/GMC-500MA holders?

A: Yes. All substitute parts maintain the 5mm x 20mm cartridge form factor and require holders identical to the original BK/GMC-500MA. Physical installation compatibility is assured across all listed substitutes.

Q: What does breaking capacity mean, and why do some substitutes have 80A versus 35A?

A: Breaking capacity is the maximum fault current a fuse can safely interrupt at rated voltage. The original BK/GMC-500MA has 35A breaking capacity. Littelfuse 201 series and SCHURTER 0034.2513 have 80A breaking capacity, providing enhanced fault protection capability. Higher breaking capacity does not affect normal operation and is acceptable for substitution.

Q: Why is melting I²t different across substitute parts?

A: Melting I²t quantifies the thermal energy required to melt the fuse element. The original part specifies 0.41. Littelfuse 201 series parts specify 0.35 (lower thermal energy required), while Littelfuse 218 series specify 2.825 (higher thermal energy required, characteristic of slow blow design). Variations reflect different fuse element designs and response characteristics but do not preclude substitution when primary parameters align.

Q: Which substitute part should be selected for new designs?

A: For new designs, select from Tier 1 equivalents (BK/GMC-500-R, BK1/GMC-500-R, GMC-500-R) to maintain identical electrical behavior and benefit from active product status. For applications requiring slow blow characteristics, select Littelfuse 218 series (0218.500MXP, 0218.500TXP). For cost-optimized designs with medium blow requirements, Littelfuse 201 series (20105000001, 20105000021) or SCHURTER 0034.2513 are acceptable.

Q: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance status. The original BK/GMC-500MA is RoHS non-compliant, making substitution necessary for applications subject to RoHS regulations.

Q: What is the difference between 20105000001 and 20105000001P?

A: Both parts are functionally equivalent 500 mA, 250 V AC fuses in the Littelfuse 201 series with identical electrical specifications. The "P" designation indicates packaging variant (201P series). Selection between these variants depends on procurement and packaging requirements; electrical performance is identical.

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