BK/ETF-6.3 Equivalent & Substitute Parts Reference

Part Overview

The BK/ETF-6.3 is a 6.3 A board mount fuse rated for 277 V AC, manufactured by Eaton - Electronics Division as part of the ETF series. This component is classified as Obsolete, which necessitates identification of equivalent substitute parts for ongoing maintenance, repair, and new design applications. The fuse features slow blow response characteristics and is designed for through-hole radial mounting in vertical orientation.

Due to its obsolete status, sourcing original BK/ETF-6.3 units may present supply chain challenges. Active equivalent parts with compatible electrical and mechanical specifications are available to ensure circuit protection continuity.

Substiute Parts

BK/ETF-6.3

Eaton - Electronics DivisionIn Stock: 1070BK/ETF-6.3 Datasheet

Current PartRFQ

SR-5-6.3A-BK

Eaton - Electronics DivisionIn Stock: 871SR-5-6.3A-BK Datasheet

SimilarRFQ

0034.6623

SCHURTER Inc.In Stock: 61450034.6623 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BK/ETF-6.3 is determined by strict alignment of the following critical parameters:

Primary Substitution Criteria:

• Current Rating: 6.3 A (exact match required)
• Response Time: Slow Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Fuse Type: Board Mount, Cartridge Style Excluded (exact match required)
• Package / Case: Radial, Can, Vertical (exact match required)
• DC Cold Resistance: 0.008 Ohms (exact match required)

Secondary Compatibility Factors:

• Voltage Rating - AC: Minimum 277 V (equal or higher acceptable)
• Operating Temperature Range: Must encompass or exceed -55°C ~ 125°C
• Melting I²t: 230 (tolerance range acceptable)
• Breaking Capacity: Minimum 63 A (equal or higher acceptable)
• Approval Agencies: Compliance with recognized standards (UL, SEMKO, VDE, cULus, etc.)

Two substitute parts meet these criteria with documented compatibility:

1. SR-5-6.3A-BK (Eaton - Electronics Division): Active status, 250 V AC rating, 63 A breaking capacity
2. 0034.6623 (SCHURTER Inc.): Active status, 250 V AC / 63 V DC rating, 63 A breaking capacity

Parameter Comparison

Engineering Selection Recommendations

For AC-Only Applications (277 V AC or lower):

Both SR-5-6.3A-BK and 0034.6623 are suitable substitutes. The SR-5-6.3A-BK maintains manufacturer continuity (Eaton) and carries broader international certifications (CCC, cULus, KC-MARK, PSE, SEMKO, VDE). However, the operating temperature range is limited to -40°C ~ 85°C, which does not fully encompass the original -55°C ~ 125°C specification.

The 0034.6623 (SCHURTER Inc.) preserves the full operating temperature range (-55°C ~ 125°C) and matches the melting I²t value (230) of the original part. It carries VDE, cURus, and KC certifications and is ROHS3 compliant.

For Mixed AC/DC Applications:

The 0034.6623 is the only substitute with explicit DC voltage rating (63 V DC), making it the appropriate choice for circuits requiring dual-voltage protection.

Voltage Derating Consideration:

Both substitutes are rated for 250 V AC, which is lower than the original 277 V AC rating. In applications operating at or near 277 V AC, verify that the 250 V AC rating provides adequate safety margin for the specific circuit design.

Inventory and Availability:

SR-5-6.3A-BK: 792 Pcs in stock 0034.6623: 6047 Pcs in stock

The 0034.6623 offers superior inventory availability.

Frequently Asked Questions (FAQ)

Q: Can SR-5-6.3A-BK be used as a direct replacement for BK/ETF-6.3 in all applications?

A: SR-5-6.3A-BK is electrically compatible for AC applications up to 250 V. However, the operating temperature range (-40°C ~ 85°C) is narrower than the original (-55°C ~ 125°C). Applications requiring operation below -40°C or above 85°C require evaluation of thermal performance or selection of an alternative substitute.

Q: What is the significance of the voltage rating difference (277 V vs. 250 V)?

A: The BK/ETF-6.3 is rated for 277 V AC, while both substitutes are rated for 250 V AC. In circuits operating at 277 V AC, the 250 V rated fuses operate at a higher percentage of their rated voltage, reducing the safety margin. Circuit design review is necessary to confirm acceptability in the specific application.

Q: Why does 0034.6623 include a DC voltage rating (63 V DC) while the original does not?

A: The 0034.6623 is designed for dual-voltage protection (AC and DC). The DC rating provides additional functionality for applications requiring protection in both AC and DC circuits. In AC-only applications, the DC rating does not affect performance.

Q: Are the physical dimension differences between BK/ETF-6.3 and the substitutes significant?

A: The BK/ETF-6.3 measures 0.329" Dia x 0.303" H (8.35mm x 7.70mm). The SR-5-6.3A-BK measures 0.335" Dia x 0.319" H (8.50mm x 8.10mm), and the 0034.6623 measures 0.335" Dia x 0.335" H (8.50mm x 8.50mm). The substitutes are slightly larger. Verify that the PCB layout and mechanical clearances accommodate the larger dimensions before implementation.

Q: What is the difference in breaking capacity between the original and substitutes?

A: The BK/ETF-6.3 has a breaking capacity of 100 A at rated voltage. Both substitutes have a breaking capacity of 63 A. Breaking capacity defines the maximum fault current the fuse can safely interrupt. In circuits with fault currents exceeding 63 A, the substitutes may not provide adequate protection. Verify the maximum available fault current in the application.

Q: Are both substitutes RoHS compliant?

A: SR-5-6.3A-BK is RoHS Compliant. The 0034.6623 is ROHS3 Compliant. Both meet current RoHS requirements. The original BK/ETF-6.3 does not specify RoHS status.

Q: Which substitute should be selected for new designs?

A: For new designs requiring full temperature range operation (-55°C ~ 125°C) and DC voltage capability, select 0034.6623. For AC-only applications with standard temperature ranges, either substitute is acceptable, with SR-5-6.3A-BK offering manufacturer continuity with Eaton.