Equivalent & Substitute Parts for AP/ETF-6.3

Part Overview

The AP/ETF-6.3 is a 6.3 A, 277 V AC board mount radial fuse manufactured by Eaton - Electronics Division. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing applications. The ETF series fuse provides slow-blow response characteristics with through-hole radial mounting configuration suitable for PCB integration. Substitute parts must maintain electrical compatibility while accommodating the transition from obsolete to active product lines.

Substiute Parts

AP/ETF-6.3

Eaton - Electronics DivisionIn Stock: 927AP/ETF-6.3 Datasheet

Current PartRFQ

SR-5-6.3A-AP

Eaton - Electronics DivisionIn Stock: 2771SR-5-6.3A-AP Datasheet

SimilarRFQ

MRT 6.3-BULK

Bel Fuse Inc.In Stock: 79238MRT 6.3-BULK Datasheet

DirectRFQ

0034.6823

SCHURTER Inc.In Stock: 13620034.6823 Datasheet

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MRT 6.3-AMMO

Bel Fuse Inc.In Stock: 116491MRT 6.3-AMMO Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the AP/ETF-6.3 is determined by the following critical parameters:

Current Rating: All substitute parts maintain the 6.3 A specification, ensuring equivalent load protection characteristics.

Voltage Rating - AC: The main part operates at 277 V AC. Substitute parts operate at 250 V AC, which represents a lower voltage rating. Substitution is valid in applications where the actual operating voltage does not exceed 250 V AC.

Response Time: All parts maintain slow-blow response characteristics, preserving transient tolerance behavior.

Mounting Configuration: All parts utilize through-hole radial mounting in vertical orientation, ensuring mechanical compatibility with existing PCB layouts.

Package Dimensions: The main part measures 0.329" Dia x 0.303" H (8.35mm x 7.70mm). Substitute parts SR-5-6.3A-AP and 0034.6823 feature slightly larger dimensions (0.335" Dia x 0.319" H or 0.335" Dia x 0.335" H), while MRT 6.3-BULK and MRT 6.3-AMMO match the original dimensions exactly.

DC Cold Resistance: All parts maintain 0.008 Ohms resistance specification.

Parameter Comparison

Engineering Selection Recommendations

Direct Dimensional Match (Preferred for PCB Retrofit):

MRT 6.3-BULK and MRT 6.3-AMMO maintain identical physical dimensions to the AP/ETF-6.3 (0.329" Dia x 0.303" H). Both are manufactured by Bel Fuse Inc. and carry active product status. MRT 6.3-AMMO is supplied in Cut Tape packaging with 116,433 units in stock, while MRT 6.3-BULK is supplied in bulk packaging with 79,224 units in stock. Both parts carry AEC-Q200 automotive qualification and comprehensive international certifications including CCC, CE, CSA, cURus, SEMKO, and VDE. Operating temperature range extends to -55°C ~ 125°C, matching the original specification. Breaking capacity is rated at 50 A, lower than the original 100 A specification.

Eaton Equivalent (Same Manufacturer):

SR-5-6.3A-AP is manufactured by Eaton - Electronics Division, the original equipment manufacturer. This part carries active product status with 2,706 units in stock. Dimensional variance is minimal (0.335" Dia x 0.319" H versus 0.329" Dia x 0.303" H). Operating temperature range is restricted to -40°C ~ 85°C, narrower than the original -55°C ~ 125°C specification. Breaking capacity is 63 A. Certifications include CCC, cULus, KC-MARK, PSE, SEMKO, and VDE.

Dual Voltage Capability (AC/DC Applications):

0034.6823 manufactured by SCHURTER Inc. provides dual voltage rating of 250 V AC and 63 V DC, suitable for applications requiring both AC and DC protection. This part carries active product status with 1,352 units in stock. Dimensional variance is moderate (0.335" Dia x 0.335" H). Operating temperature range matches the original at -55°C ~ 125°C. Breaking capacity is 63 A. Certifications include cURus, KC, and VDE. Melting I²t is elevated at 360 compared to the original 230.

Voltage Rating Consideration:

All substitute parts operate at 250 V AC maximum, compared to the original 277 V AC rating. Substitution is valid only in applications where the actual operating voltage does not exceed 250 V AC. Applications operating at or above 277 V AC require verification that the lower voltage rating is acceptable for the specific circuit design.

Frequently Asked Questions (FAQ)

Q: Can the AP/ETF-6.3 be directly replaced with MRT 6.3-AMMO or MRT 6.3-BULK?

A: Yes, for applications operating at 250 V AC or lower. Both MRT parts maintain identical current rating (6.3 A), response time (slow-blow), mounting configuration (through-hole radial), and physical dimensions (0.329" Dia x 0.303" H) as the original. Both carry active product status and comprehensive international certifications. The primary difference is reduced breaking capacity (50 A versus 100 A) and different manufacturer (Bel Fuse Inc. versus Eaton).

Q: What is the voltage compatibility issue with substitute parts?

A: The AP/ETF-6.3 is rated for 277 V AC operation. All substitute parts are rated for 250 V AC maximum. In applications where the circuit operates at 277 V AC, the substitute parts are not electrically equivalent. Substitution is valid only when the actual operating voltage does not exceed 250 V AC.

Q: Which substitute part is best for PCB retrofit applications?

A: MRT 6.3-AMMO or MRT 6.3-BULK are preferred for PCB retrofit due to exact dimensional match (0.329" Dia x 0.303" H). No PCB layout modification is required. SR-5-6.3A-AP and 0034.6823 feature slightly larger dimensions and may require PCB footprint verification before installation.

Q: Are all substitute parts RoHS compliant?

A: Yes. MRT 6.3-AMMO, MRT 6.3-BULK, SR-5-6.3A-AP, and 0034.6823 are all ROHS3 compliant. The original AP/ETF-6.3 RoHS status is not specified in available documentation.

Q: What is the difference between MRT 6.3-AMMO and MRT 6.3-BULK?

A: Both parts are electrically and mechanically identical. The difference is packaging: MRT 6.3-AMMO is supplied in Cut Tape (CT) packaging with 116,433 units in stock, while MRT 6.3-BULK is supplied in bulk packaging with 79,224 units in stock. Selection depends on procurement and assembly requirements.

Q: Does 0034.6823 offer any advantage over other substitutes?

A: 0034.6823 provides dual voltage rating (250 V AC and 63 V DC), making it suitable for applications requiring both AC and DC protection. Melting I²t is elevated at 360 compared to the original 230, providing different thermal response characteristics. This part is manufactured by SCHURTER Inc. and carries cURus, KC, and VDE certifications.

Q: What is the operating temperature range limitation of SR-5-6.3A-AP?

A: SR-5-6.3A-AP operates from -40°C to 85°C, compared to the original AP/ETF-6.3 range of -55°C to 125°C. This represents a narrower operating window. Substitution is valid only in applications where the operating temperature remains within the -40°C to 85°C range.

Q: How do breaking capacity ratings affect substitution?

A: The AP/ETF-6.3 has a breaking capacity of 100 A at rated voltage. Substitute parts have lower breaking capacities: MRT 6.3-AMMO and MRT 6.3-BULK at 50 A, and SR-5-6.3A-AP and 0034.6823 at 63 A. Breaking capacity determines the maximum fault current the fuse can safely interrupt. Applications with fault currents exceeding the substitute part's breaking capacity require circuit design review.

Q: Are all substitute parts internationally certified?

A: All substitute parts carry multiple international certifications. MRT 6.3-AMMO and MRT 6.3-BULK include AEC-Q200 automotive qualification plus CCC, CE, CSA, cURus, SEMKO, and VDE certifications. SR-5-6.3A-AP includes CCC, cULus, KC-MARK, PSE, SEMKO, and VDE certifications. 0034.6823 includes cURus, KC, and VDE certifications. Certification requirements vary by application and geographic market.