Equivalent & Substitute Parts for Eaton AP/ETF-3.15 Board Mount Fuse

Part Overview

The Eaton AP/ETF-3.15 is a 3.15 A, 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 and substitute parts that maintain functional compatibility within specified electrical and mechanical parameters. Substitute parts must satisfy the same current rating, mounting configuration, and response time characteristics while operating within acceptable voltage and temperature ranges for the target application.

Substiute Parts

AP/ETF-3.15

Eaton - Electronics DivisionIn Stock: 776AP/ETF-3.15 Datasheet

Current PartRFQ

SR-5-3.15A-AP

Eaton - Electronics DivisionIn Stock: 5364SR-5-3.15A-AP Datasheet

SimilarRFQ

0034.6820

SCHURTER Inc.In Stock: 74280034.6820 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the Eaton AP/ETF-3.15 is determined by strict alignment with the following mandatory parameters:

Current Rating: All substitute parts must be rated at 3.15 A to ensure identical overcurrent protection characteristics.

Mounting Configuration: Substitute parts must feature through-hole radial mounting in vertical orientation to ensure mechanical compatibility with existing PCB layouts and component placement.

Response Time: Substitute parts must maintain slow blow response characteristics to preserve circuit protection behavior during transient current conditions.

Fuse Type: Substitute parts must be board mount cartridge-style fuses to maintain form factor compatibility.

Voltage Rating - AC: Substitute parts must support a minimum AC voltage rating of 277 V. Parts rated at lower AC voltages (250 V) are acceptable only when the application circuit operates at or below the substitute part's voltage specification.

Physical Dimensions: Substitute parts must conform to radial, can, vertical package geometry to ensure PCB footprint compatibility.

The identified substitute parts satisfy these mandatory criteria while differing in secondary parameters such as DC voltage rating, breaking capacity, and operating temperature range. These secondary differences do not preclude substitution when the application requirements fall within the substitute part's specifications.

Parameter Comparison

Engineering Selection Recommendations

SR-5-3.15A-AP (Eaton - Electronics Division):

This substitute part maintains identical current rating and response time characteristics. The AC voltage rating of 250 V is lower than the main part's 277 V specification. Selection of this part is appropriate only when the application circuit operates at AC voltages not exceeding 250 V. The part is active in production with expanded approval certifications including cULus, KC-MARK, PSE, and VDE, providing broader regulatory compliance coverage than the obsolete main part. Operating temperature range is reduced to -40°C ~ 85°C compared to the main part's -55°C ~ 125°C range. Physical dimensions are slightly larger (0.335" Dia x 0.319" H versus 0.329" Dia x 0.303" H), requiring verification of PCB layout clearance. Breaking capacity is reduced to 35 A from 100 A.

0034.6820 (SCHURTER Inc. MST 250 Series):

This substitute part maintains identical current rating and response time characteristics. The AC voltage rating of 250 V is lower than the main part's 277 V specification; however, this part includes a DC voltage rating of 125 V, providing dual-voltage capability absent in the main part. The part is active in production with comprehensive approval certifications including CCC, cURus, KC, PSE/JET, and VDE. Operating temperature range matches the main part at -55°C ~ 125°C. Physical dimensions are slightly larger (0.335" Dia x 0.335" H), requiring verification of PCB layout clearance. Melting I²t of 76 is higher than the main part's 58, indicating different thermal response characteristics. RoHS3 compliance and REACH unaffected status are documented. Breaking capacity is 35 A AC and 50 A DC.

Both substitute parts are suitable for applications where the AC voltage requirement does not exceed 250 V and where the reduced operating temperature range (for SR-5-3.15A-AP) or increased physical dimensions do not create design constraints.

Frequently Asked Questions (FAQ)

Q: Can the SR-5-3.15A-AP substitute for the AP/ETF-3.15 in a 277 V AC circuit?

A: No. The SR-5-3.15A-AP is rated for 250 V AC maximum. Use of this part in a 277 V AC circuit exceeds its voltage specification and violates safe operating parameters. The 0034.6820 is similarly limited to 250 V AC.

Q: What is the primary difference between the two substitute parts?

A: Both maintain the 3.15 A current rating and slow blow response. The SR-5-3.15A-AP operates at -40°C ~ 85°C, while the 0034.6820 extends to -55°C ~ 125°C, matching the main part's temperature range. The 0034.6820 includes a 125 V DC rating, providing dual-voltage capability. Physical dimensions differ slightly between the two substitutes.

Q: Are the physical dimension differences significant?

A: The main part measures 0.329" Dia x 0.303" H. Both substitutes measure 0.335" Dia x 0.319" H (SR-5-3.15A-AP) or 0.335" Dia x 0.335" H (0034.6820). These increases require verification that PCB layout, component spacing, and clearance requirements are satisfied before implementation.

Q: What does "slow blow" response mean?

A: Slow blow fuses tolerate brief transient overcurrent conditions without opening. The fuse opens only when sustained overcurrent exceeds the rated current. This characteristic is maintained in both substitute parts.

Q: Can I use the 0034.6820 in a DC application?

A: The 0034.6820 is rated for 125 V DC, making it suitable for DC applications within this voltage specification. The main part and SR-5-3.15A-AP do not specify DC voltage ratings and should not be assumed to have DC capability.

Q: What approval certifications should I verify for my application?

A: The main part carries SEMKO and UL approvals. The SR-5-3.15A-AP carries CCC, cULus, KC-MARK, PSE, SEMKO, and VDE approvals. The 0034.6820 carries CCC, cURus, KC, PSE/JET, and VDE approvals. Verify that the substitute part's certifications align with your application's regulatory requirements.

Q: What is the significance of the breaking capacity difference?

A: The main part has 100 A breaking capacity at rated voltage. Both substitutes have 35 A AC breaking capacity. Breaking capacity defines the maximum fault current the fuse can safely interrupt. Applications with fault currents exceeding 35 A require evaluation of whether the substitute part's breaking capacity is adequate.

Q: Is the 0034.6820 RoHS compliant?

A: Yes, the 0034.6820 is RoHS3 compliant and REACH unaffected. The main part and SR-5-3.15A-AP do not specify RoHS status in the provided data.