Littelfuse 0272.500H Equivalent & Substitute Parts

Part Overview

The Littelfuse 0272.500H is a 500 mA board mount fuse rated for 125 V AC and 125 V DC operation. This fast-blow fuse is designed for through-hole radial mounting in the MICRO™ 272 series and is actively manufactured. Substitute parts are identified when equivalent electrical performance and mechanical compatibility are required due to inventory constraints, design revisions, or application-specific voltage requirements.

Substiute Parts

0272.500H

LittelfuseIn Stock: 11420272.500H Datasheet

Current PartRFQ

30305000421

Littelfuse Inc.In Stock: 111930305000421 Datasheet

MFR RecommendedRFQ

0272.500V

Littelfuse Inc.In Stock: 8220272.500V Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 0272.500H are classified into two categories based on electrical and mechanical compatibility:

Parametric Equivalent (0272.500V): Identical electrical specifications including 500 mA current rating, 125 V AC/DC voltage rating, fast-blow response, and identical physical dimensions. This part maintains all key parameters and is interchangeable without design modification.

MFR Recommended Substitute (30305000421): Shares the 500 mA current rating and 125 V AC voltage rating but operates at reduced DC voltage (63 V instead of 125 V). This part belongs to the TR3® 303 series with different physical dimensions (0.236" Dia x 0.315" H) and different breaking capacity (50 A). This substitute is applicable only when the application DC voltage requirement does not exceed 63 V.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement: The 0272.500V is the preferred parametric equivalent. It maintains identical electrical ratings (500 mA, 125 V AC/DC), identical physical dimensions, identical breaking capacity (10 kA), and identical operating temperature range (-55°C to 125°C). All three approval agencies (CSA, QPL, UL) are maintained. This part provides drop-in compatibility without circuit modification.

For Voltage-Constrained Applications: The 30305000421 is applicable only when the application DC voltage requirement does not exceed 63 V. While it maintains the 500 mA current rating and 125 V AC rating, the reduced DC voltage rating (63 V), different physical dimensions, reduced breaking capacity (50 A), narrower operating temperature range (-25°C to 70°C), and loss of QPL approval must be evaluated against application requirements. The increased DC cold resistance (0.532 Ohms vs. 0.167 Ohms) and reduced melting I²t (0.042 vs. 0.0716) indicate different thermal characteristics.

All substitute parts are ROHS3 compliant and actively manufactured.

Frequently Asked Questions (FAQ)

Q: Can the 0272.500V replace the 0272.500H without any circuit modifications?

A: Yes. The 0272.500V is a parametric equivalent with identical electrical specifications (500 mA, 125 V AC/DC), identical physical dimensions, and identical breaking capacity. No circuit modifications are required.

Q: Under what conditions can the 30305000421 be used as a substitute?

A: The 30305000421 can be used only when the application DC voltage requirement does not exceed 63 V. The reduced DC voltage rating is the primary limiting factor. Physical dimensions differ slightly (0.236" Dia x 0.315" H vs. 0.235" Dia x 0.287" H), which must be verified for PCB layout compatibility.

Q: What is the impact of the different breaking capacity ratings?

A: The 0272.500H and 0272.500V both have a breaking capacity of 10 kA at rated voltage. The 30305000421 has a breaking capacity of 50 A, which is significantly lower. Breaking capacity determines the maximum fault current the fuse can safely interrupt. The lower breaking capacity of the 30305000421 may not be suitable for applications with higher fault current levels.

Q: Are all substitute parts approved by the same certification agencies?

A: The 0272.500H and 0272.500V are approved by CSA, QPL, and UL. The 30305000421 is approved by CSA and UL only, with no QPL approval. Applications requiring QPL certification must use the 0272.500H or 0272.500V.

Q: What are the temperature operating range differences?

A: The 0272.500H and 0272.500V operate from -55°C to 125°C. The 30305000421 operates from -25°C to 70°C, a narrower range. Applications requiring operation below -25°C or above 70°C must use the 0272.500H or 0272.500V.

Q: How do the DC cold resistance values affect fuse selection?

A: The 0272.500H and 0272.500V have a DC cold resistance of 0.167 Ohms. The 30305000421 has a DC cold resistance of 0.532 Ohms. Higher resistance increases voltage drop across the fuse during normal operation and affects thermal characteristics. Applications sensitive to voltage drop or thermal performance must account for this difference.