BK1/S506-2.5-RG Equivalent & Substitute Parts

Part Overview

The BK1/S506-2.5-RG is a 2.5 A 250 V AC/DC glass fuse cartridge manufactured by Eaton - Electronics Division, Series S506. This slow-blow fuse cartridge operates in a 5mm x 20mm form factor and requires a compatible fuse holder for installation. The part is active in production with 1073 pieces in current inventory stock.

Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, response characteristics, and approval certifications. Alternative models provide identical functional performance within the specified parameter ranges.

Key Parameters

Parameter	Value
Current Rating	2.5 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Slow Blow
Package / Case	5mm x 20mm
Mounting Type	Requires Holder
RoHS Status	ROHS3 Compliant
Product Status	Active

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following criteria:

Primary Matching Parameters:

Current Rating: 2.5 A (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)
Response Time: Slow Blow (exact match required)
Mounting Type: Requires Holder (exact match required)

Secondary Compatibility Factors:

Breaking Capacity @ Rated Voltage: 35 A or higher
Melting I²t: Varies by series
Approval Agencies: Must include at least one common certification (cURus, CSA, VDE, PSE/JET, or equivalent)
RoHS Status: ROHS3 Compliant preferred
REACH Status: REACH Unaffected or Vendor Undefined acceptable

All substitute parts listed meet the primary matching parameters. Variations in breaking capacity, melting I²t, and specific approval certifications are noted to support application-specific selection.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Series	Current (A)	Voltage AC (V)	Response Time	Package	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ohms)	Inventory (Pcs)
BK1/S506-2.5-RG	Eaton - Electronics Division	S506	2.5	250	Slow Blow	5x20mm	35	59.4	0.0255	1073
BK/GDC-2.5A	Eaton - Electronics Division	GDC	2.5	250	Slow Blow	5x20mm	35	59.4	0.0255	1043
BK/GMD-2.5-R	Eaton - Electronics Division	GMD	2.5	250	Slow Blow	5x20mm	100	94	0.0905	1255
BK/S506-2.5-R	Eaton - Electronics Division	S506	2.5	250	Slow Blow	5x20mm	35	59.4	0.0255	3012
BK1/S506-2.5-R	Eaton - Electronics Division	S506	2.5	250	Slow Blow	5x20mm	35	59.4	0.0255	2678
GDC-2.5A	Eaton - Electronics Division	GDC	2.5	250	Slow Blow	5x20mm	35	59.4	0.0255	922
S506-2.5-R	Eaton - Electronics Division	S506	2.5	250	Slow Blow	5x20mm	35	59.4	0.0255	816
0034.3121	SCHURTER Inc.	FST 5x20	2.5	250	Slow Blow	5x20mm	35	21.9	—	2136
0034.3780	SCHURTER Inc.	FSL 5x20	2.5	250	Slow Blow	5x20mm	100	9.45	—	1752
0034.5047	SCHURTER Inc.	FTT 5x20	2.5	250	Slow Blow	5x20mm	35	258	—	1232
0034.5621.11	SCHURTER Inc.	SMD-FST	2.5	250	Slow Blow	5x20mm	35	21.9	—	1013

Engineering Selection Recommendations

Eaton - Electronics Division Substitutes (Same Manufacturer):

BK1/S506-2.5-R, BK/S506-2.5-R, and S506-2.5-R are direct equivalents within the S506 series. These parts carry identical electrical parameters, breaking capacity, and melting I²t values. All three variants are ROHS3 compliant and hold active product status. Selection among these variants depends on packaging requirements (Bulk vs. standard) and inventory availability.

BK/GDC-2.5A and GDC-2.5A (GDC series) provide equivalent electrical performance with higher breaking capacity (100 A vs. 35 A). These parts are suitable for applications requiring enhanced fault current handling. Both maintain identical current, voltage, and response characteristics.

BK1/S506-2.5-RG and BK/GDC-2.5A differ in breaking capacity and melting I²t. Selection depends on circuit protection requirements and fault current levels in the target application.

SCHURTER Inc. Substitutes (Cross-Manufacturer):

SCHURTER FST 5x20 series (0034.3121, 0034.5621.11) matches all primary electrical parameters with lower melting I²t values (21.9 vs. 59.4). These parts are ROHS3 compliant and hold active product status. Operating temperature range extends to -55°C ~ 125°C.

SCHURTER FSL 5x20 (0034.3780) provides higher breaking capacity (100 A) with significantly lower melting I²t (9.45). This part is suitable for fast-response protection applications. Operating temperature range is -40°C ~ 85°C.

SCHURTER FTT 5x20 (0034.5047) offers the highest melting I²t value (258) among all substitutes, providing extended time-delay characteristics. Operating temperature range is -40°C ~ 85°C.

Approval Certifications:

All Eaton parts carry multi-agency certifications including BSI, CCC, CSA, CURUS, IMQ, PSE/JET, SEMKO, and VDE. SCHURTER parts carry cURus, VDE, PSE/JET, and CCC certifications. Cross-manufacturer substitution is supported by overlapping certification coverage.

Frequently Asked Questions (FAQ)

Q: Can BK1/S506-2.5-RG be directly replaced with BK/S506-2.5-R?

A: Yes. Both parts are Eaton S506 series fuses with identical electrical ratings (2.5 A, 250 V AC), response time (Slow Blow), package dimensions (5x20mm), and breaking capacity (35 A). The primary difference is packaging format. Both are ROHS3 compliant and active in production.

Q: What is the difference between Eaton S506 and GDC series fuses?

A: Both series match the primary electrical parameters (2.5 A, 250 V AC, Slow Blow, 5x20mm). The GDC series provides higher breaking capacity (100 A vs. 35 A) and higher melting I²t (94 vs. 59.4). Selection depends on circuit fault current levels and protection requirements.

Q: Can SCHURTER fuses replace Eaton fuses in this application?

A: Yes, provided all primary parameters match: 2.5 A current rating, 250 V AC voltage rating, Slow Blow response, and 5x20mm package. SCHURTER FST and SMD-FST series are direct equivalents. FSL series offers higher breaking capacity. FTT series provides extended time-delay characteristics. Cross-manufacturer substitution is supported by common approval certifications (cURus, VDE, PSE/JET).

Q: What does melting I²t indicate, and why does it vary among substitutes?

A: Melting I²t is the thermal energy required to melt the fuse element, expressed in ampere-squared seconds. Higher values indicate longer time-delay before fuse operation. BK1/S506-2.5-RG has melting I²t of 59.4. SCHURTER FST series has 21.9 (faster response), while FTT series has 258 (extended delay). Selection depends on circuit inrush current characteristics and protection timing requirements.

Q: Are all listed substitutes ROHS3 compliant?

A: Yes. All Eaton and SCHURTER parts listed are ROHS3 compliant. All parts carry REACH Unaffected or Vendor Undefined status, confirming compliance with environmental regulations.

Q: What approval certifications are required for this fuse category?

A: BK1/S506-2.5-RG carries BSI, CCC, CSA, CURUS, IMQ, PSE/JET, SEMKO, and VDE certifications. SCHURTER equivalents carry cURus, VDE, PSE/JET, and CCC certifications. Overlapping certifications support cross-manufacturer substitution. Verify specific certification requirements for your target application and geographic market.

Q: Can fuses with different breaking capacities be interchanged?

A: Fuses with different breaking capacities (35 A vs. 100 A) are electrically interchangeable for normal operation at rated current. However, breaking capacity determines the maximum fault current the fuse can safely interrupt. Select breaking capacity based on the maximum available fault current in your circuit. Higher breaking capacity provides additional safety margin but does not affect normal operation.

Q: What is the operating temperature range for BK1/S506-2.5-RG?

A: Operating temperature range is not specified in the provided data for BK1/S506-2.5-RG. SCHURTER FST series operates -55°C ~ 125°C. SCHURTER FSL and FTT series operate -40°C ~ 85°C. Verify temperature requirements for your specific application environment.

Q: Does packaging format (Bulk vs. standard) affect electrical performance?

A: No. Packaging format affects only order quantity and delivery logistics. Electrical performance, ratings, and response characteristics are identical regardless of packaging designation. Select packaging based on procurement and inventory management requirements.

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