SCHURTER 0034.4273 Board Mount Fuse — Equivalent & Substitute Parts

Part Overview

The SCHURTER 0034.4273 is a 250 mA, 125 V AC/DC board mount fuse with fast-blow response characteristics, designed for through-hole radial mounting in radial can package format. This part carries an obsolete product status, making identification of functionally equivalent alternatives essential for ongoing design support and procurement continuity. Substitute parts must maintain identical electrical ratings, response time classification, and mechanical compatibility with the original mounting footprint.

Substiute Parts

0034.4273

SCHURTER Inc.In Stock: 8500034.4273 Datasheet

Current PartRFQ

0034.4213

SCHURTER Inc.In Stock: 17870034.4213 Datasheet

Parametric EquivalentRFQ

0034.4243

SCHURTER Inc.In Stock: 11150034.4243 Datasheet

Parametric EquivalentRFQ

0273.250H

Littelfuse Inc.In Stock: 15970273.250H Datasheet

DirectRFQ

0272.250H

Littelfuse Inc.In Stock: 9910272.250H Datasheet

SimilarRFQ

0272.250V

Littelfuse Inc.In Stock: 11960272.250V Datasheet

SimilarRFQ

0273.250V

Littelfuse Inc.In Stock: 10510273.250V Datasheet

SimilarRFQ

0279.250V

Littelfuse Inc.In Stock: 8840279.250V Datasheet

SimilarRFQ

30302500421

Littelfuse Inc.In Stock: 93730302500421 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following critical parameters:

Primary Equivalence Criteria:

• Current Rating: 250 mA (exact match required)
• Voltage Rating AC: 125 V (exact match required)
• Voltage Rating DC: 125 V (exact match required)
• Response Time: Fast Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Fuse Type: Board Mount (Cartridge Style Excluded)

Secondary Compatibility Factors:

• Package / Case format (Radial, Can)
• Melting I²t value (0.0055 to 0.0064 range acceptable for thermal coordination)
• Physical dimensions (within manufacturing tolerance)
• RoHS3 compliance status

Substitute parts are grouped into two categories:

Category A — Parametric Equivalents (SCHURTER MSF 125 Series): Parts 0034.4213 and 0034.4243 maintain identical electrical specifications and are manufactured by the original equipment supplier. These parts differ only in breaking capacity (100A vs. 300A) and product status (Active vs. Obsolete), with no impact on circuit protection function.

Category B — Direct and Similar Equivalents (Littelfuse MICRO™ and TR3® Series): Parts 0273.250H, 0272.250H, 0272.250V, 0273.250V, and 0279.250V meet all primary equivalence criteria with identical current, voltage, and response time ratings. Physical dimensions vary slightly within acceptable tolerance. Part 30302500421 meets current and AC voltage requirements but operates at reduced DC voltage (63 V vs. 125 V) and is classified as a similar equivalent only.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Preferred):

SCHURTER 0034.4213 and 0034.4243 are the primary substitutes. Both parts maintain identical electrical specifications, mechanical dimensions, and thermal characteristics as the obsolete 0034.4273. Both carry Active product status and ROHS3 compliance. Selection between these two SCHURTER alternatives depends on procurement availability and inventory levels.

For Cross-Manufacturer Substitution:

Littelfuse MICRO™ 273 series (0273.250H, 0273.250V) and MICRO™ 279 series (0279.250V) provide full electrical equivalence with enhanced breaking capacity (10kA vs. 300A) and extended temperature range (-55°C lower limit). These parts are certified by CSA, QPL, and UL, meeting or exceeding the original cURus certification. Physical dimensions are within acceptable tolerance for through-hole mounting.

Littelfuse MICRO™ 272 series (0272.250H, 0272.250V) offers the widest operating temperature range (-55°C ~ 125°C) and highest breaking capacity, with slightly reduced physical dimensions that remain compatible with standard through-hole footprints.

Not Recommended for Direct Substitution:

Part 30302500421 (Littelfuse TR3® 303) operates at reduced DC voltage (63 V vs. 125 V) and is classified as a similar equivalent only. This part is suitable only for applications where the circuit operates at or below 63 V DC.

Frequently Asked Questions (FAQ)

Q: Can SCHURTER 0034.4213 or 0034.4243 be used as direct replacements for the obsolete 0034.4273?

A: Yes. Both parts maintain identical current rating (250 mA), voltage ratings (125 V AC/DC), response time (Fast Blow), and physical dimensions. The difference in breaking capacity (100A vs. 300A) does not affect circuit protection function in standard applications. Both are Active status parts with ROHS3 compliance.

Q: What is the difference between Littelfuse MICRO™ 273 and MICRO™ 272 series fuses?

A: Both series meet all primary electrical equivalence criteria. The MICRO™ 272 series offers a wider operating temperature range (-55°C ~ 125°C vs. -55°C ~ 85°C) and slightly smaller physical dimensions (0.235" Dia x 0.287" H vs. 0.250" Dia x 0.350" H). Selection depends on thermal environment requirements and available board space.

Q: Are Littelfuse MICRO™ fuses compatible with the original SCHURTER mounting footprint?

A: Physical dimensions are within acceptable tolerance for through-hole radial mounting. MICRO™ 273 and 279 series maintain the same diameter and height as the original part (0.250" Dia x 0.350" H vs. 0.252" Dia x 0.346" H). MICRO™ 272 series has slightly reduced dimensions but remains compatible with standard through-hole spacing.

Q: Can part 30302500421 be used in place of the 0034.4273?

A: Part 30302500421 is suitable only for applications operating at 63 V DC or lower. The original 0034.4273 is rated for 125 V DC. Use this part only if your circuit voltage is confirmed to be 63 V DC or less.

Q: What certifications do the substitute parts carry?

A: SCHURTER 0034.4213 and 0034.4243 carry cURus certification. Littelfuse MICRO™ series (0273.250H, 0273.250V, 0272.250H, 0272.250V, 0279.250V) carry CSA, QPL, and UL certifications. All substitute parts are ROHS3 compliant and REACH unaffected.

Q: How do melting I²t values affect substitution?

A: The original 0034.4273 has a melting I²t of 0.0055. Littelfuse MICRO™ and TR3® series have values ranging from 0.0064 to 0.0082. These variations reflect different thermal response characteristics but do not prevent substitution when all primary electrical parameters match. Thermal coordination with circuit design should be verified for critical applications.