BK/ETF-800MA Equivalent & Substitute Parts

Part Overview

The BK/ETF-800MA is an 800 mA, 277 V AC board mount fuse with slow blow response characteristics, designed for through hole radial mounting in vertical orientation. This component is classified as obsolete, necessitating identification of active equivalent parts for new designs and ongoing maintenance applications. The fuse features a radial can package with 100 A breaking capacity at rated voltage and operates across a temperature range of -55°C to 125°C.

Substiute Parts

BK/ETF-800MA

Eaton - Electronics DivisionIn Stock: 818BK/ETF-800MA Datasheet

Current PartRFQ

SR-5-800MA-BK

Eaton - Electronics DivisionIn Stock: 765SR-5-800MA-BK Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the BK/ETF-800MA is determined by the following critical parameters:

Current Rating Match: The substitute part must maintain 800 mA current rating to ensure equivalent circuit protection.

Mounting Configuration: Both the main part and substitute must support through hole radial mounting in vertical orientation to ensure mechanical compatibility with existing PCB layouts.

Response Characteristic: Slow blow response time must be preserved to maintain protection against transient overcurrent conditions.

Package Geometry: Radial can vertical package style ensures physical fit within board mount fuse footprints.

The SR-5-800MA-BK meets these core substitution criteria. However, the voltage rating differs: the substitute operates at 250 V AC versus the original 277 V AC specification. This represents a voltage derating and is permissible only in applications where the actual circuit voltage does not exceed 250 V AC.

Parameter Comparison

Engineering Selection Recommendations

For Direct Substitution (Same Voltage Rating Required):

The SR-5-800MA-BK is the designated active equivalent from Eaton - Electronics Division. This part maintains identical current rating, response time, and mounting configuration. The substitute is active in production status, ensuring long-term availability and supply chain continuity compared to the obsolete BK/ETF-800MA.

Voltage Rating Consideration:

The SR-5-800MA-BK operates at 250 V AC, representing a 27 V reduction from the original 277 V specification. This substitute is applicable only in circuits where the maximum operating voltage does not exceed 250 V AC. Applications requiring the full 277 V rating cannot use this substitute without circuit redesign.

Compliance and Certifications:

The SR-5-800MA-BK carries expanded regulatory approvals (CCC, cULus, KC-MARK, SEMKO, VDE) compared to the original part (SEMKO, UL), providing broader market compliance. The substitute is RoHS compliant, whereas the original part status is not specified.

Temperature Range Derating:

The substitute operates within -40°C to 85°C, narrower than the original -55°C to 125°C range. Applications requiring operation below -40°C or above 85°C cannot use this substitute.

Breaking Capacity Difference:

The substitute exhibits 35 A breaking capacity versus the original 100 A. This represents a significant reduction in fault current handling capability and must be evaluated against circuit fault current levels.

Frequently Asked Questions (FAQ)

Q: Can SR-5-800MA-BK be used as a direct replacement for BK/ETF-800MA in all applications?

A: No. The SR-5-800MA-BK is suitable only for applications where circuit voltage does not exceed 250 V AC and operating temperature remains within -40°C to 85°C. The original part is rated for 277 V AC and -55°C to 125°C operation.

Q: What is the significance of the voltage rating difference between these parts?

A: The BK/ETF-800MA is rated for 277 V AC operation, while SR-5-800MA-BK is rated for 250 V AC. Using a lower-rated fuse in a higher-voltage circuit creates a safety hazard. Substitution is permissible only when actual circuit voltage is confirmed to be 250 V AC or lower.

Q: Are the physical dimensions compatible?

A: The parts are similar but not identical. BK/ETF-800MA measures 0.329" diameter × 0.303" height, while SR-5-800MA-BK measures 0.335" diameter × 0.319" height. Both are radial can vertical packages and fit standard board mount fuse footprints, but dimensional verification against PCB layout is required.

Q: What does the breaking capacity difference mean for circuit protection?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. The original part breaks 100 A at rated voltage, while the substitute breaks 35 A. In circuits with fault currents exceeding 35 A, the substitute may not safely interrupt the fault condition.

Q: Is the SR-5-800MA-BK RoHS compliant?

A: Yes, SR-5-800MA-BK is RoHS compliant. The original BK/ETF-800MA RoHS status is not specified in the provided data.

Q: What regulatory approvals does each part carry?

A: BK/ETF-800MA carries SEMKO and UL approvals. SR-5-800MA-BK carries CCC, cULus, KC-MARK, SEMKO, and VDE approvals, providing broader international compliance coverage.

Q: Can I use SR-5-800MA-BK in applications requiring -55°C operation?

A: No. The SR-5-800MA-BK minimum operating temperature is -40°C. Applications requiring operation at -55°C cannot use this substitute.