Littelfuse 0477012.MXP Ceramic Fuse 12A 500VAC 400VDC 5x20mm - Equivalent & Substitute Parts

Part Overview

The Littelfuse 0477012.MXP is a 12 A ceramic cartridge fuse rated for 500 V AC and 400 V DC operation in a 5mm x 20mm form factor. This fuse requires a holder for installation and provides slow-blow response characteristics suitable for circuit protection applications. The part maintains active product status with full RoHS3 compliance and cURus/PSE approval certifications. Equivalent substitute parts are available from Eaton - Electronics Division to support procurement flexibility and supply chain continuity.

Substiute Parts

0477012.MXP

LittelfuseIn Stock: 32040477012.MXP Datasheet

Current PartRFQ

BK-S505H-V-12-R

Eaton - Electronics DivisionIn Stock: 1545BK-S505H-V-12-R Datasheet

MFR RecommendedRFQ

BK1-S505H-12-R

Eaton - Electronics DivisionIn Stock: 2692BK1-S505H-12-R Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the Littelfuse 0477012.MXP is determined by the following critical parameters:

• Current Rating: 12 A (exact match required)
• Voltage Rating - AC: 500 V (exact match required)
• Voltage Rating - DC: 400 V (exact match required)
• Fuse Type: Cartridge, Ceramic (exact match required)
• Response Time: Slow Blow (exact match required)
• Package / Case: 5mm x 20mm (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)
• RoHS Status: ROHS3 Compliant (exact match required)

Two Eaton - Electronics Division parts meet these substitution criteria: BK-S505H-V-12-R (MFR Recommended) and BK1-S505H-12-R (Parametric Equivalent). Both parts satisfy all electrical and mechanical parameters required for direct substitution.

Parameter Comparison

Engineering Selection Recommendations

Both Eaton substitute parts satisfy the core electrical and mechanical requirements for direct substitution with the Littelfuse 0477012.MXP.

BK-S505H-V-12-R (MFR Recommended): This part features through-hole mounting with axial orientation and is designated as the manufacturer-recommended substitute. It carries cURus and UL certifications with 200A breaking capacity at rated voltage.

BK1-S505H-12-R (Parametric Equivalent): This part maintains the requires-holder mounting configuration identical to the original Littelfuse design. It carries cURus and UL certifications with 200A breaking capacity at rated voltage and provides dimensional compatibility with existing fuse holder installations.

Selection between these substitutes depends on mounting configuration requirements. The BK1-S505H-12-R maintains mechanical compatibility with existing Littelfuse 0477012.MXP holder installations. The BK-S505H-V-12-R offers alternative through-hole mounting for applications requiring axial orientation.

Frequently Asked Questions (FAQ)

Q: Can BK-S505H-V-12-R and BK1-S505H-12-R be used interchangeably with Littelfuse 0477012.MXP?

A: Both parts meet all critical electrical parameters (12 A, 500 V AC, 400 V DC, slow-blow ceramic cartridge). The primary difference is mounting type. BK1-S505H-12-R maintains the requires-holder configuration of the original part. BK-S505H-V-12-R uses through-hole axial mounting. Selection depends on your application's mounting requirements.

Q: What is the difference between "MFR Recommended" and "Parametric Equivalent" substitutes?

A: Both designations indicate valid substitution based on electrical and mechanical parameters. MFR Recommended (BK-S505H-V-12-R) is the manufacturer's primary alternative. Parametric Equivalent (BK1-S505H-12-R) matches all critical specifications and maintains identical mounting configuration to the original part.

Q: Are there dimensional differences between these parts?

A: The Littelfuse 0477012.MXP and Eaton BK1-S505H-12-R share identical dimensions (0.205" Dia x 0.787" L / 5.20mm x 20.00mm). The Eaton BK-S505H-V-12-R has slightly larger dimensions (0.218" Dia x 0.831" L / 5.54mm x 21.10mm) due to its through-hole axial design.

Q: Do all three parts have the same certifications?

A: The Littelfuse part carries cULus and PSE certifications. Both Eaton substitutes carry cURus and UL certifications. All three parts are ROHS3 compliant and REACH unaffected.

Q: What is the difference in melting I²t values?

A: The Littelfuse 0477012.MXP has a melting I²t of 576, while both Eaton substitutes have a melting I²t of 550. This represents a minor difference in thermal response characteristics within the slow-blow fuse category.